Microneedles: quick and easy delivery methods of vaccines

PubMed Central

2017-01-01

Vaccination is the most efficient method for infectious disease prevention. Parenteral injections such as intramuscular, intradermal, and subcutaneous injections have several advantages in vaccine delivery, but there are many drawbacks. Thus, the development of a new vaccine delivery system has long been required. Recently, microneedles have been attracting attention as new vaccination tools. Microneedle is a highly effective transdermal vaccine delivery method due to its mechanism of action, painlessness, and ease of use. Here, we summarized the characteristics of microneedles and the possibilities as a new vaccine delivery route. PMID:28775980

A Review of Intra- and Extracellular Antigen Delivery Systems for Virus Vaccines of Finfish

PubMed Central

Munang'andu, Hetron Mweemba; Evensen, Øystein

2015-01-01

Vaccine efficacy in aquaculture has for a long time depended on evaluating relative percent survival and antibody responses after vaccination. However, current advances in vaccine immunology show that the route in which antigens are delivered into cells is deterministic of the type of adaptive immune response evoked by vaccination. Antigens delivered by the intracellular route induce MHC-I restricted CD8+ responses while antigens presented through the extracellular route activate MHC-II restricted CD4+ responses implying that the route of antigen delivery is a conduit to induction of B- or T-cell immune responses. In finfish, different antigen delivery systems have been explored that include live, DNA, inactivated whole virus, fusion protein, virus-like particles, and subunit vaccines although mechanisms linking these delivery systems to protective immunity have not been studied in detail. Hence, in this review we provide a synopsis of different strategies used to administer viral antigens via the intra- or extracellular compartments. Further, we highlight the differences in immune responses induced by antigens processed by the endogenous route compared to exogenously processed antigens. Overall, we anticipate that the synopsis put together in this review will shed insights into limitations and successes of the current vaccination strategies used in finfish vaccinology. PMID:26065009

Intradermal delivery of vaccines: potential benefits and current challenges

PubMed Central

Hickling, JK; Jones, KR; Friede, M; Chen, D; Kristensen, D

2011-01-01

Abstract Delivery of vaccine antigens to the dermis and/or epidermis of human skin (i.e. intradermal delivery) might be more efficient than injection into the muscle or subcutaneous tissue, thereby reducing the volumes of antigen. This is known as dose-sparing and has been demonstrated in clinical trials with some, but not all, vaccines. Dose-sparing could be beneficial to immunization programmes by potentially reducing the costs of purchase, distribution and storage of vaccines; increasing vaccine availability and effectiveness. The data obtained with intradermal delivery of some vaccines are encouraging and warrant further study and development; however significant gaps in knowledge and operational challenges such as reformulation, optimizing vaccine presentation and development of novel devices to aid intradermal vaccine delivery need to be addressed. Modelling of the costs and potential savings resulting from intradermal delivery should be done to provide realistic expectations of the potential benefits and to support cases for investment. Implementation and uptake of intradermal vaccine delivery requires further research and development, which depends upon collaboration between multiple stakeholders in the field of vaccination. PMID:21379418

Recent advances in microparticle and nanoparticle delivery vehicles for mucosal vaccination.

PubMed

McNeela, E A; Lavelle, E C

2012-01-01

The great potential of mucosal vaccination is widely accepted but progress in the clinical development of subunit mucosal vaccines has been disappointing. Of the available approaches, the use of polymer-based microparticles is attractive because these delivery vehicles can be specifically tailored for vaccines and they offer the potential for integration of adjuvant. Here we address recent developments in the use of particulates as mucosal vaccines and the potential of novel targeting strategies, formulation approaches and adjuvant combinations to enhance the efficacy of particle-based mucosal vaccines. This review discusses the current status of mucosal vaccines based on particles and highlights several of the strategies that are currently under investigation for improving their immunogenicity. These include enhancing the stability of formulations in the luminal environment, increasing uptake by specifically targeting particles to mucosal inductive sites, and augmenting immunogenicity through co-formulation with immunostimulatory agents.

Bovine adenovirus-3 as a vaccine delivery vehicle.

PubMed

Ayalew, Lisanework E; Kumar, Pankaj; Gaba, Amit; Makadiya, Niraj; Tikoo, Suresh K

2015-01-15

The use of vaccines is an effective and relatively inexpensive means of controlling infectious diseases, which cause heavy economic losses to the livestock industry through animal loss, decreased productivity, treatment expenses and decreased carcass quality. However, some vaccines produced by conventional means are imperfect in many respects including virulence, safety and efficacy. Moreover, there are no vaccines for some animal diseases. Although genetic engineering has provided new ways of producing effective vaccines, the cost of production for veterinary use is a critical criterion for selecting the method of production and delivery of vaccines. The cost effective production and intrinsic ability to enter cells has made adenovirus vectors a highly efficient tool for delivery of vaccine antigens. Moreover, adenoviruses induce both humoral and cellular immune responses to expressed vaccine antigens. Since nonhuman adenoviruses are species specific, the development of animal specific adenoviruses as vaccine delivery vectors is being evaluated. This review summarizes the work related to the development of bovine adenovirus-3 as a vaccine delivery vehicle in animals, particularly cattle. Copyright © 2014 Elsevier Ltd. All rights reserved.

Oral Delivery of Probiotics Expressing Dendritic Cell-Targeting Peptide Fused with Porcine Epidemic Diarrhea Virus COE Antigen: A Promising Vaccine Strategy against PEDV.

PubMed

Wang, Xiaona; Wang, Li; Huang, Xuewei; Ma, Sunting; Yu, Meiling; Shi, Wen; Qiao, Xinyuan; Tang, Lijie; Xu, Yigang; Li, Yijing

2017-10-25

Porcine epidemic diarrhea virus (PEDV), an enteric coronavirus, is the causative agent of porcine epidemic diarrhea (PED) that damages intestinal epithelial cells and results in severe diarrhea and dehydration in neonatal suckling pigs with up to 100% mortality. The oral vaccine route is reported as a promising approach for inducing protective immunity against PEDV invasion. Furthermore, dendritic cells (DCs), professional antigen-presenting cells, link humoral and cellular immune responses for homeostasis of the intestinal immune environment. In this study, in order to explore an efficient oral vaccine against PEDV infection, a mucosal DC-targeting oral vaccine was developed using Lactobacillus casei to deliver the DC-targeting peptide (DCpep) fused with the PEDV core neutralizing epitope (COE) antigen. This probiotic vaccine could efficiently elicit secretory immunoglobulin A (SIgA)-based mucosal and immunoglobulin G (IgG)-based humoral immune responses via oral vaccination in vivo. Significant differences ( p < 0.05) in the immune response levels were observed between probiotics expressing the COE-DCpep fusion protein and COE antigen alone, suggesting better immune efficiency of the probiotics vaccine expressing the DC-targeting peptide fused with PEDV COE antigen. This mucosal DC-targeting oral vaccine delivery effectively enhances vaccine antigen delivery efficiency, providing a useful strategy to induce efficient immune responses against PEDV infection.

Veterinary vaccine nanotechnology: pulmonary and nasal delivery in livestock animals.

PubMed

Calderon-Nieva, Daniella; Goonewardene, Kalhari Bandara; Gomis, Susantha; Foldvari, Marianna

2017-08-01

Veterinary vaccine development has several similarities with human vaccine development to improve the overall health and well-being of species. However, veterinary goals lean more toward feasible large-scale administration methods and low cost to high benefit immunization. Since the respiratory mucosa is easily accessible and most infectious agents begin their infection cycle at the mucosa, immunization through the respiratory route has been a highly attractive vaccine delivery strategy against infectious diseases. Additionally, vaccines administered via the respiratory mucosa could lower costs by removing the need of trained medical personnel, and lowering doses yet achieving similar or increased immune stimulation. The respiratory route often brings challenges in antigen delivery efficiency with enough potency to induce immunity. Nanoparticle (NP) technology has been shown to enhance immune activation by producing higher antibody titers and protection. Although specific mechanisms between NPs and biological membranes are still under investigation, physical parameters such as particle size and shape, as well as biological tissue distribution including mucociliary clearance influence the protection and delivery of antigens to the site of action and uptake by target cells. For respiratory delivery, various biomaterials such as mucoadhesive polymers, lipids, and polysaccharides have shown enhanced antibody production or protection in comparison to antigen alone. This review presents promising NPs administered via the nasal or pulmonary routes for veterinary applications specifically focusing on livestock animals including poultry.

Advances in fish vaccine delivery.

PubMed

Plant, Karen P; Lapatra, Scott E

2011-12-01

Disease prevention is essential to the continued development of aquaculture around the world. Vaccination is the most effective method of combating disease and currently there are a number of vaccines commercially available for use in fish. The majority of aquatic vaccines are delivered by injection, which is by far the most effective method when compared to oral or immersion deliveries. However it is labor intensive, costly and not feasible for large numbers of fish under 20 g. Attempts to develop novel oral and immersion delivery methods have resulted in varying degrees of success but may have great potential for the future. Copyright © 2011 Elsevier Ltd. All rights reserved.

Minipigs as an Animal Model for Dermal Vaccine Delivery

PubMed Central

Ploemen, Ivo HJ; Hirschberg, Hoang JHB; Kraan, Heleen; Zeltner, Adrian; van Kuijk, Sandra; Lankveld, Danielle PK; Royals, Michael; Kersten, Gideon FA; Amorij, Jean-Pierre

2014-01-01

Appropriate animal models for intradermal vaccine delivery are scarce. Given the high similarity of their skin anatomy to that of humans, minipigs may be a suitable model for dermal vaccine delivery. Here we describe the immunization of Göttingen minipigs by using intradermal and intramuscular delivery of hepatitis B surface antigen (HBsAg). Intradermal vaccine delivery by needle and syringe and by needle-free jet injection induced humoral antiHBsAg responses. Priming immunization by using the disposable syringe jet injector (DSJI) resulted in a higher antibody titer than did conventional intradermal immunization and a titer comparable to that after intramuscular vaccination with HBsAg and Al(OH)3 adjuvant. This study highlights the utility of the minipig model in vaccine studies assessing the efficacy of conventional and novel methods of dermal delivery. Moreover, we include suggestions regarding working with minipigs during dermal vaccine delivery studies, thereby fostering future work in this area of vaccinology. PMID:24512961

Improving the safety of vaccine delivery.

PubMed

Evans, Huw P; Cooper, Alison; Williams, Huw; Carson-Stevens, Andrew

2016-05-03

Vaccines save millions of lives per annum as an integral part of community primary care provision worldwide. Adverse events due to the vaccine delivery process outnumber those arising from the pharmacological properties of the vaccines themselves. Whilst one in three patients receiving a vaccine will encounter some form of error, little is known about their underlying causes and how to mitigate them in practice. Patient safety incident reporting systems and adverse drug event surveillance offer a rich opportunity for understanding the underlying causes of those errors. Reducing harm relies on the identification and implementation of changes to improve vaccine safety at multiple levels: from patient interventions through to organizational actions at local, national and international levels. Here we highlight the potential for maximizing learning from patient safety incident reports to improve the quality and safety of vaccine delivery.

PLGA particulate delivery systems for subunit vaccines: Linking particle properties to immunogenicity.

PubMed

Silva, A L; Soema, P C; Slütter, B; Ossendorp, F; Jiskoot, W

2016-04-02

Among the emerging subunit vaccines are recombinant protein- and synthetic peptide-based vaccine formulations. However, proteins and peptides have a low intrinsic immunogenicity. A common strategy to overcome this is to co-deliver (an) antigen(s) with (an) immune modulator(s) by co-encapsulating them in a particulate delivery system, such as poly(lactic-co-glycolic acid) (PLGA) particles. Particulate PLGA formulations offer many advantages for antigen delivery as they are biocompatible and biodegradable; can protect the antigens from degradation and clearance; allow for co-encapsulation of antigens and immune modulators; can be targeted to antigen presenting cells; and their particulate nature can increase uptake and cross-presentation by mimicking the size and shape of an invading pathogen. In this review we discuss the pros and cons of using PLGA particulate formulations for subunit vaccine delivery and provide an overview of formulation parameters that influence their adjuvanticity and the ensuing immune response.

Comparative performance of a licensed anthrax vaccine versus electroporation based delivery of a PA encoding DNA vaccine in rhesus macaques.

PubMed

Livingston, Brian D; Little, Stephen F; Luxembourg, Alain; Ellefsen, Barry; Hannaman, Drew

2010-01-22

DNA vaccination is a promising immunization strategy that could be applied in the development of vaccines for a variety of prophylactic and therapeutic indications. Utilizing anthrax protective antigen as a model antigen, we demonstrate that electroporation mediated delivery enhanced the immunogenicity of DNA vaccines in nonhuman primates over 100-fold as compared to conventional intramuscular injection. Two administrations of a DNA vaccine with electroporation elicited anthrax toxin neutralizing antibody responses in 100% of rhesus macaques. Toxin neutralizing antibodies were sustained for the nearly 1-year study duration and were correlated with protection against subsequent lethal Bacillus anthracis spore challenge. Collectively, electroporation mediated DNA vaccination conferred protection comparable to that observed following vaccination with an FDA approved anthrax vaccine.

Microneedle and mucosal delivery of influenza vaccines

PubMed Central

Kang, Sang-Moo; Song, Jae-Min; Kim, Yeu-Chun

2017-01-01

In recent years with the threat of pandemic influenza and other public health needs, alternative vaccination methods other than intramuscular immunization have received great attention. The skin and mucosal surfaces are attractive sites probably because of both non-invasive access to the vaccine delivery and unique immunological responses. Intradermal vaccines using a microinjection system (BD Soluvia) and intranasal vaccines (FluMist) are licensed. As a new vaccination method, solid microneedles have been developed using a simple device that may be suitable for self-administration. Because coated micorneedle influenza vaccines are administered in the solid state, developing formulations maintaining the stability of influenza vaccines is an important issue to be considered. Marketable microneedle devices and clinical trials remain to be developed. Other alternative mucosal routes such as oral and intranasal delivery systems are also attractive for inducing cross protective mucosal immunity but effective non-live mucosal vaccines remain to be developed. PMID:22697052

Cluster Randomized Trial of a Toolkit and Early Vaccine Delivery to Improve Childhood Influenza Vaccination Rates in Primary Care

PubMed Central

Zimmerman, Richard K.; Nowalk, Mary Patricia; Lin, Chyongchiou Jeng; Hannibal, Kristin; Moehling, Krissy K.; Huang, Hsin-Hui; Matambanadzo, Annamore; Troy, Judith; Allred, Norma J.; Gallik, Greg; Reis, Evelyn C.

2014-01-01

Purpose To increase childhood influenza vaccination rates using a toolkit and early vaccine delivery in a randomized cluster trial. Methods Twenty primary care practices treating children (range for n=536-8,183) were randomly assigned to Intervention and Control arms to test the effectiveness of an evidence-based practice improvement toolkit (4 Pillars Toolkit) and early vaccine supplies for use among disadvantaged children on influenza vaccination rates among children 6 months-18 years. Follow-up staff meetings and surveys were used to assess use and acceptability of the intervention strategies in the Intervention arm. Rates for the 2010-2011 and 2011-2012 influenza seasons were compared. Two-level generalized linear mixed modeling was used to evaluate outcomes. Results Overall increases in influenza vaccination rates were significantly greater in the Intervention arm (7.9 percentage points) compared with the Control arm (4.4 percentage points; P<0.034). These rate changes represent 4522 additional doses in the Intervention arm vs. 1,390 additional doses in the Control arm. This effect of the intervention was observed despite the fact that rates increased significantly in both arms - 8/10 Intervention (P<0.001) and 7/10 Control sites (P-values 0.04 to <0.001). Rates in two Intervention sites with pre-intervention vaccination rates >58% did not significantly increase. In regression analyses, a child's likelihood of being vaccinated was significantly higher with: younger age, white race (Odds ratio [OR]=1.29; 95% confidence interval [CI]=1.23-1.34), having commercial insurance (OR=1.30; 95%CI=1.25-1.35), higher pre-intervention practice vaccination rate (OR=1.25; 95%CI=1.16-1.34), and being in the Intervention arm (OR=1.23; 95%CI=1.01-1.50). Early delivery of influenza vaccine was rated by Intervention practices as an effective strategy for raising rates. Conclusions Implementation of a multi-strategy toolkit and early vaccine supplies can significantly improve

Enabling skin vaccination using new delivery technologies

PubMed Central

Kim, Yeu-Chun; Prausnitz, Mark R.

2011-01-01

The skin is known to be a highly immunogenic site for vaccination, but few vaccines in clinical use target skin largely because conventional intradermal injection is difficult and unreliable to perform. Now, a number of new or newly adapted delivery technologies have been shown to administer vaccine to the skin either by non-invasive or minimally invasive methods. Non-invasive methods include high-velocity powder and liquid jet injection, as well as diffusion-based patches in combination with skin abrasion, thermal ablation, ultrasound, electroporation, and chemical enhancers. Minimally invasive methods are generally based on small needles, including solid microneedle patches, hollow microneedle injections, and tattoo guns. The introduction of these advanced delivery technologies can make the skin a site for simple, reliable vaccination that increases vaccine immunogenicity and offers logistical advantages to improve the speed and coverage of vaccination. PMID:21799951

Enabling skin vaccination using new delivery technologies

PubMed Central

Kim, Yeu-Chun; Prausnitz, Mark R.

2011-01-01

The skin is known to be a highly immunogenic site for vaccination, but few vaccines in clinical use target skin largely because conventional intradermal injection is difficult and unreliable to perform. Now, a number of new or newly adapted delivery technologies have been shown to administer vaccine to the skin either by non-invasive or minimally invasive methods. Non-invasive methods include high-velocity powder and liquid jet injection, as well as diffusion-based patches in combination with skin abrasion, thermal ablation, ultrasound, electroporation, and chemical enhancers. Minimally invasive methods are generally based on small needles, including solid microneedle patches, hollow microneedle injections and tattoo guns. The introduction of these advanced delivery technologies can make the skin a site for simple, reliable vaccination that increases vaccine immunogenicity and offers logistical advantages to improve the speed and coverage of vaccination. PMID:21472533

Preliminary results from direct-to-facility vaccine deliveries in Kano, Nigeria.

PubMed

Aina, Muyi; Igbokwe, Uchenna; Jegede, Leke; Fagge, Rabiu; Thompson, Adam; Mahmoud, Nasir

2017-04-19

As part of its vaccine supply chain redesign efforts, Kano state now pushes vaccines directly from 6 state stores to primary health centers equipped with solar refrigerators. Our objective is to describe preliminary results from the first 20months of Kano's direct vaccine delivery operations. This is a retrospective review of Kano's direct vaccine delivery program. We analyzed trends in health facility vaccine stock levels, and examined the relationship between stock-out rates and each of cascade vaccine deliveries and timeliness of deliveries. Analysis of vaccination trends was based on administrative data from 27 sentinel health facilities. Costs for both the in-sourced and out-sourced approaches were estimated using a bottoms-up model-based approach. Overall stock adequacy increased from 54% in the first delivery cycle to 68% by cycle 33. Conversely, stock-out rates decreased from 41% to 10% over the same period. Similar trends were observed in the out-sourced and in-sourced programs. Stock-out rates rose incrementally with increasing number of cascade facilities, and delays in vaccine deliveries correlated strongly with stock-out rates. Recognizing that stock availability is one of many factors contributing to vaccinations, we nonetheless compared pre- and post- direct deliveries vaccinations in sentinel facilities, and found statistically significant upward trends for 4 out of 6 antigens. 1 antigen (measles) showed an upward trend that was not statistically significant. Hepatitis b vaccinations declined during the period. Overall, there appeared to be a one-year lag between commencement of direct deliveries and the increase in number of vaccinations. Weighted average cost per delivery is US$29.8 and cost per child immunized is US$0.7 per year. Direct vaccine delivery to health facilities in Kano, through a streamlined architecture, has resulted in decreased stock-outs and improved stock adequacy. Concurrent operation of insourced and outsourced programs has

Production of recombinant subunit vaccines: protein immunogens, live delivery systems and nucleic acid vaccines.

PubMed

Liljeqvist, S; Ståhl, S

1999-07-30

The first scientific attempts to control an infectious disease can be attributed to Edward Jenner, who, in 1796 inoculated an 8-year-old boy with cowpox (vaccinia), giving the boy protection against subsequent challenge with virulent smallpox. Thanks to the successful development of vaccines, many major diseases, such as diphtheria, poliomyelitis and measles, are nowadays kept under control, and in the case of smallpox, the dream of eradication has been fulfilled. Yet, there is a growing need for improvements of existing vaccines in terms of increased efficacy and improved safety, besides the development of completely new vaccines. Better technological possibilities, combined with increased knowledge in related fields, such as immunology and molecular biology, allow for new vaccination strategies. Besides the classical whole-cell vaccines, consisting of killed or attenuated pathogens, new vaccines based on the subunit principle, have been developed, e.g. the Hepatitis B surface protein vaccine and the Haemophilus influenzae type b vaccine. Recombinant techniques are now dominating in the strive for an ideal vaccine, being safe and cheap, heat-stable and easy to administer, preferably single-dose, and capable of inducing broad immune response with life-long memory both in adults and in infants. This review will describe different recombinant approaches used in the development of novel subunit vaccines, including design and production of protein immunogens, the development of live delivery systems and the state-of-the-art for nucleic acids vaccines.

Polyethylenimine-based polyplex delivery of self-replicating RNA vaccines.

PubMed

Démoulins, Thomas; Milona, Panagiota; Englezou, Pavlos C; Ebensen, Thomas; Schulze, Kai; Suter, Rolf; Pichon, Chantal; Midoux, Patrick; Guzmán, Carlos A; Ruggli, Nicolas; McCullough, Kenneth C

2016-04-01

Self-amplifying replicon RNA (RepRNA) are large molecules (12-14 kb); their self-replication amplifies mRNA template numbers, affording several rounds of antigen production, effectively increasing vaccine antigen payloads. Their sensitivity to RNase-sensitivity and inefficient uptake by dendritic cells (DCs) - absolute requirements for vaccine design - were tackled by condensing RepRNA into synthetic, nanoparticulate, polyethylenimine (PEI)-polyplex delivery vehicles. Polyplex-delivery formulations for small RNA molecules cannot be transferred to RepRNA due to its greater size and complexity; the N:P charge ratio and impact of RepRNA folding would influence polyplex condensation, post-delivery decompaction and the cytosolic release essential for RepRNA translation. Polyplex-formulations proved successful for delivery of RepRNA encoding influenza virus hemagglutinin and nucleocapsid to DCs. Cytosolic translocation was facilitated, leading to RepRNA translation. This efficacy was confirmed in vivo, inducing both humoral and cellular immune responses. Accordingly, this paper describes the first PEI-polyplexes providing efficient delivery of the complex and large, self-amplifying RepRNA vaccines. The use of self-amplifying replicon RNA (RepRNA) to increase vaccine antigen payloads can potentially be useful in effective vaccine design. Nonetheless, its use is limited by the degradation during the uptake process. Here, the authors attempted to solve this problem by packaging RepRNA using polyethylenimine (PEI)-polyplex delivery vehicles. The efficacy was confirmed in vivo by the appropriate humoral and cellular immune responses. This novel delivery method may prove to be very useful for future vaccine design. Copyright © 2015 Elsevier Inc. All rights reserved.

Oral Cholera Vaccination Delivery Cost in Low- and Middle-Income Countries: An Analysis Based on Systematic Review.

PubMed

Mogasale, Vittal; Ramani, Enusa; Wee, Hyeseung; Kim, Jerome H

2016-12-01

Use of the oral cholera vaccine (OCV) is a vital short-term strategy to control cholera in endemic areas with poor water and sanitation infrastructure. Identifying, estimating, and categorizing the delivery costs of OCV campaigns are useful in analyzing cost-effectiveness, understanding vaccine affordability, and in planning and decision making by program managers and policy makers. To review and re-estimate oral cholera vaccination program costs and propose a new standardized categorization that can help in collation, analysis, and comparison of delivery costs across countries. Peer reviewed publications listed in PubMed database, Google Scholar and World Health Organization (WHO) websites and unpublished data from organizations involved in oral cholera vaccination. The publications and reports containing oral cholera vaccination delivery costs, conducted in low- and middle-income countries based on World Bank Classification. Limits are humans and publication date before December 31st, 2014. No participants are involved, only costs are collected. Oral cholera vaccination and cost estimation. A systematic review was conducted using pre-defined inclusion and exclusion criteria. Cost items were categorized into four main cost groups: vaccination program preparation, vaccine administration, adverse events following immunization and vaccine procurement; the first three groups constituting the vaccine delivery costs. The costs were re-estimated in 2014 US dollars (US$) and in international dollar (I$). Ten studies were identified and included in the analysis. The vaccine delivery costs ranged from US$0.36 to US$ 6.32 (in US$2014) which was equivalent to I$ 0.99 to I$ 16.81 (in I$2014). The vaccine procurement costs ranged from US$ 0.29 to US$ 29.70 (in US$2014), which was equivalent to I$ 0.72 to I$ 78.96 (in I$2014). The delivery costs in routine immunization systems were lowest from US$ 0.36 (in US$2014) equivalent to I$ 0.99 (in I$2014). The reported cost categories

Peptide/protein vaccine delivery system based on PLGA particles.

PubMed

Allahyari, Mojgan; Mohit, Elham

2016-03-03

Due to the excellent safety profile of poly (D,L-lactide-co-glycolide) (PLGA) particles in human, and their biodegradability, many studies have focused on the application of PLGA particles as a controlled-release vaccine delivery system. Antigenic proteins/peptides can be encapsulated into or adsorbed to the surface of PLGA particles. The gradual release of loaded antigens from PLGA particles is necessary for the induction of efficient immunity. Various factors can influence protein release rates from PLGA particles, which can be defined intrinsic features of the polymer, particle characteristics as well as protein and environmental related factors. The use of PLGA particles encapsulating antigens of different diseases such as hepatitis B, tuberculosis, chlamydia, malaria, leishmania, toxoplasma and allergy antigens will be described herein. The co-delivery of antigens and immunostimulants (IS) with PLGA particles can prevent the systemic adverse effects of immunopotentiators and activate both dendritic cells (DCs) and natural killer (NKs) cells, consequently enhancing the therapeutic efficacy of antigen-loaded PLGA particles. We will review co-delivery of different TLR ligands with antigens in various models, highlighting the specific strengths and weaknesses of the system. Strategies to enhance the immunotherapeutic effect of DC-based vaccine using PLGA particles can be designed to target DCs by functionalized PLGA particle encapsulating siRNAs of suppressive gene, and disease specific antigens. Finally, specific examples of cellular targeting where decorating the surface of PLGA particles target orally administrated vaccine to M-cells will be highlighted.

Peptide/protein vaccine delivery system based on PLGA particles

PubMed Central

Allahyari, Mojgan; Mohit, Elham

2016-01-01

abstract Due to the excellent safety profile of poly (D,L-lactide-co-glycolide) (PLGA) particles in human, and their biodegradability, many studies have focused on the application of PLGA particles as a controlled-release vaccine delivery system. Antigenic proteins/peptides can be encapsulated into or adsorbed to the surface of PLGA particles. The gradual release of loaded antigens from PLGA particles is necessary for the induction of efficient immunity. Various factors can influence protein release rates from PLGA particles, which can be defined intrinsic features of the polymer, particle characteristics as well as protein and environmental related factors. The use of PLGA particles encapsulating antigens of different diseases such as hepatitis B, tuberculosis, chlamydia, malaria, leishmania, toxoplasma and allergy antigens will be described herein. The co-delivery of antigens and immunostimulants (IS) with PLGA particles can prevent the systemic adverse effects of immunopotentiators and activate both dendritic cells (DCs) and natural killer (NKs) cells, consequently enhancing the therapeutic efficacy of antigen-loaded PLGA particles. We will review co-delivery of different TLR ligands with antigens in various models, highlighting the specific strengths and weaknesses of the system. Strategies to enhance the immunotherapeutic effect of DC-based vaccine using PLGA particles can be designed to target DCs by functionalized PLGA particle encapsulating siRNAs of suppressive gene, and disease specific antigens. Finally, specific examples of cellular targeting where decorating the surface of PLGA particles target orally administrated vaccine to M-cells will be highlighted. PMID:26513024

Novel adjuvants & delivery vehicles for vaccines development: a road ahead.

PubMed

Mohan, Teena; Verma, Priyanka; Rao, D Nageswara

2013-11-01

The pure recombinant and synthetic antigens used in modern day vaccines are generally less immunogenic than older style live/attenuated and killed whole organism vaccines. One can improve the quality of vaccine production by incorporating immunomodulators or adjuvants with modified delivery vehicles viz. liposomes, immune stimulating complexes (ISCOMs), micro/nanospheres apart from alum, being used as gold standard. Adjuvants are used to augment the effect of a vaccine by stimulating the immune system to respond to the vaccine, more vigorously, and thus providing increased immunity to a particular disease. Adjuvants accomplish this task by mimicking specific sets of evolutionary conserved molecules which include lipopolysaccharides (LPS), components of bacterial cell wall, endocytosed nucleic acids such as dsRNA, ssDNA and unmethylated CpG dinucleotide containing DNA. This review provides information on various vaccine adjuvants and delivery vehicles being developed to date. From literature, it seems that the humoral immune responses have been observed for most adjuvants and delivery platforms while viral-vector, ISCOMs and Montanides have shown cytotoxic T-cell response in the clinical trials. MF59 and MPL® have elicited Th1 responses, and virus-like particles (VLPs), non-degradable nanoparticle and liposomes have also generated cellular immunity. Such vaccine components have also been evaluated for alternative routes of administration with clinical success reported for intranasal delivery of viral-vectors and proteosomes and oral delivery of VLP vaccines.

Novel adjuvants & delivery vehicles for vaccines development: A road ahead

PubMed Central

Mohan, Teena; Verma, Priyanka; Rao, D. Nageswara

2013-01-01

The pure recombinant and synthetic antigens used in modern day vaccines are generally less immunogenic than older style live/attenuated and killed whole organism vaccines. One can improve the quality of vaccine production by incorporating immunomodulators or adjuvants with modified delivery vehicles viz. liposomes, immune stimulating complexes (ISCOMs), micro/nanospheres apart from alum, being used as gold standard. Adjuvants are used to augment the effect of a vaccine by stimulating the immune system to respond to the vaccine, more vigorously, and thus providing increased immunity to a particular disease. Adjuvants accomplish this task by mimicking specific sets of evolutionary conserved molecules which include lipopolysaccharides (LPS), components of bacterial cell wall, endocytosed nucleic acids such as dsRNA, ssDNA and unmethylated CpG dinucleotide containing DNA. This review provides information on various vaccine adjuvants and delivery vehicles being developed to date. From literature, it seems that the humoral immune responses have been observed for most adjuvants and delivery platforms while viral-vector, ISCOMs and Montanides have shown cytotoxic T-cell response in the clinical trials. MF59 and MPL® have elicited Th1 responses, and virus-like particles (VLPs), non-degradable nanoparticle and liposomes have also generated cellular immunity. Such vaccine components have also been evaluated for alternative routes of administration with clinical success reported for intranasal delivery of viral-vectors and proteosomes and oral delivery of VLP vaccines. PMID:24434331

Microneedles for drug and vaccine delivery

PubMed Central

Kim, Yeu-Chun; Park, Jung-Hwan; Prausnitz, Mark R.

2012-01-01

Microneedles were first conceptualized for drug delivery many decades ago, but only became the subject of significant research starting in the mid-1990’s when microfabrication technology enabled their manufacture as (i) solid microneedles for skin pretreatment to increase skin permeability, (ii) microneedles coated with drug that dissolves off in the skin, (iii) polymer microneedles that encapsulate drug and fully dissolve in the skin and (iv) hollow microneedles for drug infusion into the skin. As shown in more than 350 papers now published in the field, microneedles have been used to deliver a broad range of different low molecular weight drugs, biotherapeutics and vaccines, including published human studies with a number of small-molecule and protein drugs and vaccines. Influenza vaccination using a hollow microneedle is in widespread clinical use and a number of solid microneedle products are sold for cosmetic purposes. In addition to applications in the skin, microneedles have also been adapted for delivery of bioactives into the eye and into cells. Successful application of microneedles depends on device function that facilitates microneedle insertion and possible infusion into skin, skin recovery after microneedle removal, and drug stability during manufacturing, storage and delivery, and on patient outcomes, including lack of pain, skin irritation and skin infection, in addition to drug efficacy and safety. Building off a strong technology base and multiple demonstrations of successful drug delivery, microneedles are poised to advance further into clinical practice to enable better pharmaceutical therapies, vaccination and other applications. PMID:22575858

Vaccine vial stopper performance for fractional dose delivery of vaccines.

PubMed

Jarrahian, Courtney; Myers, Daniel; Creelman, Ben; Saxon, Eugene; Zehrung, Darin

2017-07-03

Shortages of vaccines such as inactivated poliovirus and yellow fever vaccines have been addressed by administering reduced-or fractional-doses, as recommended by the World Health Organization Strategic Advisory Group of Experts on Immunization, to expand population coverage in countries at risk. We evaluated 3 kinds of vaccine vial stoppers to assess their performance after increased piercing from repeated withdrawal of doses needed when using fractional doses (0.1 mL) from presentations intended for full-dose (0.5 mL) delivery. Self-sealing capacity and fragmentation of the stopper were assessed via modified versions of international standard protocols. All stoppers maintained self-sealing capacity after 100 punctures. The damage to stoppers measured as the fragmentation rate was within the target of ≤ 10% of punctures resulting in a fragment after as many as 50 punctures. We concluded that stopper failure is not likely to be a concern if existing vaccine vials containing up to 10 regular doses are used up to 50 times for fractional dose delivery.

Vaccine vial stopper performance for fractional dose delivery of vaccines

PubMed Central

Jarrahian, Courtney; Myers, Daniel; Creelman, Ben; Saxon, Eugene; Zehrung, Darin

2017-01-01

ABSTRACT Shortages of vaccines such as inactivated poliovirus and yellow fever vaccines have been addressed by administering reduced—or fractional—doses, as recommended by the World Health Organization Strategic Advisory Group of Experts on Immunization, to expand population coverage in countries at risk. We evaluated 3 kinds of vaccine vial stoppers to assess their performance after increased piercing from repeated withdrawal of doses needed when using fractional doses (0.1 mL) from presentations intended for full-dose (0.5 mL) delivery. Self-sealing capacity and fragmentation of the stopper were assessed via modified versions of international standard protocols. All stoppers maintained self-sealing capacity after 100 punctures. The damage to stoppers measured as the fragmentation rate was within the target of ≤ 10% of punctures resulting in a fragment after as many as 50 punctures. We concluded that stopper failure is not likely to be a concern if existing vaccine vials containing up to 10 regular doses are used up to 50 times for fractional dose delivery. PMID:28463054

Mucosal vaccination--an old but still vital strategy.

PubMed

Długońska, Henryka; Grzybowski, Marcin

2012-01-01

The basic premise of vaccinology is to achieve strong protective immunity against defined infectious agents by a vaccine mimicking the effects of natural primary exposure to a pathogen. Because an exposure of humans and animals to microbes occurs mostly through mucosal surfaces, targeting the mucosa seems a rational and efficient vaccination strategy. Many experimental and clinical data confirmed that mucosal immunization offers many advantages over widely used in human and veterinary medicine subcutaneous or intramuscular immunization. In the present article selected aspects regarding mucosal vaccination are discussed. The structure and function of mucosa-associated lymphoid tissue (MALT), comprised of four main mucosal compartments forming a structural and functional unity as well as pivotal cellular MALT components (dendritic and M cells) were briefly characterized. Particular attention was focused on the mode of simple but efficacious delivery of vaccine antigens to mucosal surfaces. A few trials to generate potential mucosal vaccines against toxoplasmosis introduced by nasal or oral routes to experimental animals are also presented.

Strategies and hurdles using DNA vaccines to fish

PubMed Central

2014-01-01

DNA vaccinations against fish viral diseases as IHNV at commercial level in Canada against VHSV at experimental level are both success stories. DNA vaccination strategies against many other viral diseases have, however, not yet yielded sufficient results in terms of protection. There is an obvious need to combat many other viral diseases within aquaculture where inactivated vaccines fail. There are many explanations to why DNA vaccine strategies against other viral diseases fail to induce protective immune responses in fish. These obstacles include: 1) too low immunogenicity of the transgene, 2) too low expression of the transgene that is supposed to induce protection, 3) suboptimal immune responses, and 4) too high degradation rate of the delivered plasmid DNA. There are also uncertainties with regard distribution and degradation of DNA vaccines that may have implications for safety and regulatory requirements that need to be clarified. By combining plasmid DNA with different kind of adjuvants one can increase the immunogenicity of the transgene antigen – and perhaps increase the vaccine efficacy. By using molecular adjuvants with or without in combination with targeting assemblies one may expect different responses compared with naked DNA. This includes targeting of DNA vaccines to antigen presenting cells as a central factor in improving their potencies and efficacies by means of encapsulating the DNA vaccine in certain carriers systems that may increase transgene and MHC expression. This review will focus on DNA vaccine delivery, by the use of biodegradable PLGA particles as vehicles for plasmid DNA mainly in fish. PMID:24552235

Marker vaccine strategies and candidate CSFV marker vaccines.

PubMed

Dong, Xiao-Nan; Chen, Ying-Hua

2007-01-04

Classical swine fever (CSF) is an economically important highly contagious disease of swine worldwide. Classical swine fever virus (CSFV) is its etiological agent, and the only natural hosts are domestic pigs and wild boars. Although field CSFV strains vary in the virulence, they all result in serious losses in pig industry. Highly virulent field strains generally cause acute disease and high mortality; moderately virulent field strains raise subacute or chronic infections; postnatal infection by low virulent field strains produces subclinical infection and mortality in the new-born piglets. CSFV can cross the placental barrier, and this transplacental transmission usually results in mortality of fetuses and birth of congenitally infected pigs with a late-onset disease and death. Two main strategies to control CSF epidemic are systematic prophylactic vaccination with live attenuated vaccines (such as C-strain) and non-vaccination stamping-out policy. But neither of them is satisfying enough. Marker vaccine and companion serological diagnostic test is thought to be a promising strategy for future control and eradication of CSF. During the past 15 years, various candidate marker vaccines were constructed and evaluated in the animal experiments, including recombinant chimeric vaccines, recombinant deletion vaccines, DNA vaccines, subunit vaccines and peptide vaccines. Among them, two subunit vaccines entered the large scale marker vaccine trial of EU in 1999. Although they failed to fulfil all the demands of the Scientific Veterinary Committee, they successfully induced solid immunity against CSFV in the vaccinated pigs. It can be expected that new potent marker vaccines might be commercially available and used in systematic prophylactic vaccination campaign or emergency vaccination in the next 15 years. Here, we summarized current strategies and candidate CSFV marker vaccines. These strategies and methods are also helpful for the development of new

Oral Cholera Vaccination Delivery Cost in Low- and Middle-Income Countries: An Analysis Based on Systematic Review

PubMed Central

Ramani, Enusa; Wee, Hyeseung; Kim, Jerome H.

2016-01-01

Background Use of the oral cholera vaccine (OCV) is a vital short-term strategy to control cholera in endemic areas with poor water and sanitation infrastructure. Identifying, estimating, and categorizing the delivery costs of OCV campaigns are useful in analyzing cost-effectiveness, understanding vaccine affordability, and in planning and decision making by program managers and policy makers. Objectives To review and re-estimate oral cholera vaccination program costs and propose a new standardized categorization that can help in collation, analysis, and comparison of delivery costs across countries. Data sources Peer reviewed publications listed in PubMed database, Google Scholar and World Health Organization (WHO) websites and unpublished data from organizations involved in oral cholera vaccination. Study eligibility criteria The publications and reports containing oral cholera vaccination delivery costs, conducted in low- and middle-income countries based on World Bank Classification. Limits are humans and publication date before December 31st, 2014. Participants No participants are involved, only costs are collected. Intervention Oral cholera vaccination and cost estimation. Study appraisal and synthesis method A systematic review was conducted using pre-defined inclusion and exclusion criteria. Cost items were categorized into four main cost groups: vaccination program preparation, vaccine administration, adverse events following immunization and vaccine procurement; the first three groups constituting the vaccine delivery costs. The costs were re-estimated in 2014 US dollars (US$) and in international dollar (I$). Results Ten studies were identified and included in the analysis. The vaccine delivery costs ranged from US$0.36 to US$ 6.32 (in US$2014) which was equivalent to I$ 0.99 to I$ 16.81 (in I$2014). The vaccine procurement costs ranged from US$ 0.29 to US$ 29.70 (in US$2014), which was equivalent to I$ 0.72 to I$ 78.96 (in I$2014). The delivery costs in

Assessment of transcutaneous vaccine delivery by optical coherence tomography Assessment of transcutaneous vaccine delivery by OCT

NASA Astrophysics Data System (ADS)

Kamali, T.; Doronin, A.; Rattanapak, T.; Hook, S.; Meglinski, I.

2012-08-01

Immunization is one of the most efficient and cost-effective means for the prevention of diseases. The latest trend for inducing protective immunity is topical application of vaccines to intact skin rather than invasive administration via injection. Apart from being a non-invasive route of drug delivery, skin itself also offers advantages through the presence of cells of the immune system in both the dermis and epidermis. However, vaccine penetration through the outermost layers of skin is limited by the barrier provided by the Stratum corneum. In the current study utilizing conventional Optical Coherence Tomography (OCT) we investigate the transcutaneous delivery of a nano- particulate peptide vaccine into mouse skin in vivo. We demonstrate that a front of molecular diffusion within the skin can be clearly observed by using cross-correlations of successive 2D OCT images. Thus, OCT provides a unique tool for quantitative assessment of dynamics of diffusion of drugs, target compounds, analytes, cosmetics and various chemical agents in biological tissues in vivo.

Strategies to implement maternal vaccination: A comparison between standing orders for midwife delivery, a hospital based maternal immunisation service and primary care.

PubMed

Krishnaswamy, Sushena; Wallace, Euan M; Buttery, Jim; Giles, Michelle L

2018-03-20

Maternal vaccination is a safe and effective strategy to reduce maternal and neonatal morbidity and mortality from pertussis and influenza. However, despite recommendations for maternal vaccination since 2010, uptake remains suboptimal. Barriers to uptake have been studied widely and include lack of integration of vaccination into routine pregnancy care and access to vaccination services. Standing orders for administration of vaccines without the need for a physician review or prescription have been demonstrated to improve uptake as part of multi-model interventions to increase antenatal influenza and post-partum pertussis vaccination. Monash Health is a university-affiliated, public healthcare network in Melbourne, Australia providing maternity services across three hospitals. In this study we compared three different immunisation models - an immunisation nurse-led immunisation service, standing orders for midwife-administered pertussis vaccination within pregnancy care clinics, and delivery by general practitioners in primary care. Uptake of maternal pertussis vaccine was measured as recorded in the state-wide perinatal data collection tool. Uptake improved significantly at all three hospitals over the study period with the most significant change (39% to 91%, p < .001) noted at the hospital where standing orders were introduced. Our study highlights the diversity of immunisation service models available in maternity care settings. We demonstrated significant improvement in uptake of maternal pertussis vaccination with introduction of midwife-administered vaccination but each maternity service should consider the model best suited to their needs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Strategy of topical vaccination with nanoparticles

NASA Astrophysics Data System (ADS)

Jung, Sascha; Patzelt, Alexa; Otberg, Nina; Thiede, Gisela; Sterry, Wolfram; Lademann, Juergen

2009-03-01

Liposomes in the nanosize range have been recognized as a versatile drug delivery system of both hydrophilic and lipophilic molecules. In order to develop a liposome-based topical vaccination strategy, five different types of liposomes were tested as a putative vaccine delivery system on pig ear skin. The investigated liposomes mainly varied in size, lipid composition, and surface charge. Using hydrophilic and hydrophobic fluorescent dyes as model drugs, penetration behavior was studied by means of confocal laser scanning microscopy of intact skin and histological sections, respectively. Follicular penetration of the liposomes was measured in comparison to a standard, nonliposomal formulation at different time points. Dependent on time but independent of their different characters, the liposomes showed a significantly higher penetration depth into the hair follicles compared to the standard formulation. The standard formulation reached a relative penetration depth of 30% of the full hair follicle length after seven days, whereas amphoteric and cationic liposomes had reached ~70%. Penetration depth of negatively charged liposomes did not exceed 50% of the total follicle length. The fluorescence dyes were mainly detected in the hair follicle; only a small amount of dye was found in the upper parts of the epidermis.

Strategy of topical vaccination with nanoparticles.

PubMed

Jung, Sascha; Patzelt, Alexa; Otberg, Nina; Thiede, Gisela; Sterry, Wolfram; Lademann, Juergen

2009-01-01

Liposomes in the nanosize range have been recognized as a versatile drug delivery system of both hydrophilic and lipophilic molecules. In order to develop a liposome-based topical vaccination strategy, five different types of liposomes were tested as a putative vaccine delivery system on pig ear skin. The investigated liposomes mainly varied in size, lipid composition, and surface charge. Using hydrophilic and hydrophobic fluorescent dyes as model drugs, penetration behavior was studied by means of confocal laser scanning microscopy of intact skin and histological sections, respectively. Follicular penetration of the liposomes was measured in comparison to a standard, nonliposomal formulation at different time points. Dependent on time but independent of their different characters, the liposomes showed a significantly higher penetration depth into the hair follicles compared to the standard formulation. The standard formulation reached a relative penetration depth of 30% of the full hair follicle length after seven days, whereas amphoteric and cationic liposomes had reached approximately 70%. Penetration depth of negatively charged liposomes did not exceed 50% of the total follicle length. The fluorescence dyes were mainly detected in the hair follicle; only a small amount of dye was found in the upper parts of the epidermis.

Recent trends in vaccine delivery systems: A review

PubMed Central

Saroja, CH; Lakshmi, PK; Bhaskaran, Shyamala

2011-01-01

Vaccines are the preparations given to patients to evoke immune responses leading to the production of antibodies (humoral) or cell-mediated responses that will combat infectious agents or noninfectious conditions such as malignancies. Alarming safety profile of live vaccines, weak immunogenicity of sub-unit vaccines and immunization, failure due to poor patient compliance to booster doses which should potentiate prime doses are few strong reasons, which necessitated the development of new generation of prophylactic and therapeutic vaccines to promote effective immunization. Attempts are being made to deliver vaccines through carriers as they control the spatial and temporal presentation of antigens to immune system thus leading to their sustained release and targeting. Hence, lower doses of weak immunogens can be effectively directed to stimulate immune responses and eliminate the need for the administration of prime and booster doses as a part of conventional vaccination regimen. This paper reviews carrier systems such as liposomes, microspheres, nanoparticles, dendrimers, micellar systems, ISCOMs, plant-derived viruses which are now being investigated and developed as vaccine delivery systems. This paper also describes various aspects of “needle-free technologies” used to administer the vaccine delivery systems through different routes into the human body. PMID:23071924

Novel vaccine development strategies for inducing mucosal immunity

PubMed Central

Fujkuyama, Yoshiko; Tokuhara, Daisuke; Kataoka, Kosuke; Gilbert, Rebekah S; McGhee, Jerry R; Yuki, Yoshikazu; Kiyono, Hiroshi; Fujihashi, Kohtaro

2012-01-01

To develop protective immune responses against mucosal pathogens, the delivery route and adjuvants for vaccination are important. The host, however, strives to maintain mucosal homeostasis by responding to mucosal antigens with tolerance, instead of immune activation. Thus, induction of mucosal immunity through vaccination is a rather difficult task, and potent mucosal adjuvants, vectors or other special delivery systems are often used, especially in the elderly. By taking advantage of the common mucosal immune system, the targeting of mucosal dendritic cells and microfold epithelial cells may facilitate the induction of effective mucosal immunity. Thus, novel routes of immunization and antigen delivery systems also show great potential for the development of effective and safe mucosal vaccines against various pathogens. The purpose of this review is to introduce several recent approaches to induce mucosal immunity to vaccines, with an emphasis on mucosal tissue targeting, new immunization routes and delivery systems. Defining the mechanisms of mucosal vaccines is as important as their efficacy and safety, and in this article, examples of recent approaches, which will likely accelerate progress in mucosal vaccine development, are discussed. PMID:22380827

Mitochondrion: A Promising Target for Nanoparticle-Based Vaccine Delivery Systems

PubMed Central

Wen, Ru; Umeano, Afoma C.; Francis, Lily; Sharma, Nivita; Tundup, Smanla; Dhar, Shanta

2016-01-01

Vaccination is one of the most popular technologies in disease prevention and eradication. It is promising to improve immunization efficiency by using vectors and/or adjuvant delivery systems. Nanoparticle (NP)-based delivery systems have attracted increasing interest due to enhancement of antigen uptake via prevention of vaccine degradation in the biological environment and the intrinsic immune-stimulatory properties of the materials. Mitochondria play paramount roles in cell life and death and are promising targets for vaccine delivery systems to effectively induce immune responses. In this review, we focus on NPs-based delivery systems with surfaces that can be manipulated by using mitochondria targeting moieties for intervention in health and disease. PMID:27258316

Financing and systems barriers to seasonal influenza vaccine delivery in community settings.

PubMed

Penfold, Robert B; Rusinak, Donna; Lieu, Tracy A; Shefer, Abigail; Messonnier, Mark; Lee, Grace M

2011-12-06

Recommendations for annual seasonal influenza vaccination have expanded to now include >300 million children and adults each year. Community settings have become increasingly important venues for influenza vaccination. We sought to identify barriers to and solutions for expanding influenza vaccination in community settings. Semi-structured telephone interviews were conducted from 01/09 to 06/10 with a range of stakeholders involved in influenza vaccination, including health plans, medical services firms, retail based clinics, pharmacies, schools, and state and local public health immunization programs. Participants (n=65) were asked about barriers and feasible solutions to influenza vaccine delivery to children and adults in community settings. Key themes were identified through iterative coding using a grounded theory approach. Stakeholders identified specific financial barriers to influenza vaccine delivery in 3 major areas: purchase and distribution, delivery, and reimbursement. Limited purchasing power, the uncertain nature of public demand, and unpredictable timing of influenza vaccine supply were important barriers to enhance delivery in community settings. Barriers to delivery included complexities in running off-site clinics, especially in school settings, the need to manage publicly vs. privately purchased vaccines separately, and state-to-state variability in requirements for credentialing, physician oversight, and reporting. Reimbursement barriers included a protracted credentialing process, the need to determine insurance eligibility at point-of-service, and lack of a billing infrastructure in off-site clinics. Opportunities to mitigate financial barriers to influenza vaccine delivery in community settings focused on coordination across providers and the role of public health as a "trusted broker" to overcome existing challenges. Financial and systems barriers hamper the optimal use of community settings to effectively deliver influenza vaccines. Public

Particulate delivery systems for biodefense subunit vaccines.

PubMed

Bramwell, Vincent W; Eyles, Jim E; Oya Alpar, H

2005-06-17

Expanding identification of potentially protective subunit antigens and correlates of protection has provided a basis for the introduction of safer vaccines. Despite encouraging results in animal models, the significant potential of particulate delivery systems in vaccine design has not yet translated into effective vaccines available for use in humans. This review article will focus on the current status of the development of particulate vaccines, mainly liposomes and bio-degradable polymers, against potential agents for biowarfare: plague, anthrax, botulinum, and smallpox; and filoviruses: Marburg and Ebola.

A Novel Vaccine Delivery Model of the Apicomplexan Eimeria tenella Expressing Eimeria maxima Antigen Protects Chickens against Infection of the Two Parasites

PubMed Central

Tang, Xinming; Liu, Xianyong; Yin, Guangwen; Suo, Jingxia; Tao, Geru; Zhang, Sixin; Suo, Xun

2018-01-01

Vaccine delivery is critical in antigen discovery and vaccine efficacy and safety. The diversity of infectious diseases in humans and livestock has required the development of varied delivery vehicles to target different pathogens. In livestock animals, previous strategies for the development of coccidiosis vaccines have encountered several hurdles, limiting the development of multiple species vaccine formulations. Here, we describe a novel vaccine delivery system using transgenic Eimeria tenella expressing immunodominant antigens of Eimeria maxima. In this delivery system, the immune mapped protein 1 of E. maxima (EmIMP1) was delivered by the closely related species of E. tenella to the host immune system during the whole endogenous life cycle. The overexpression of the exogenous antigen did not interfere with the reproduction and immunogenicity of transgenic Eimeria. After immunization with the transgenic parasite, we detected EmIMP1’s and E. maxima oocyst antigens’ specific humoral and cellular immune responses. In particular, we observed partial protection of chickens immunized with transgenic E. tenella against subsequent E. maxima infections. Our results demonstrate that the transgenic Eimeria parasite is an ideal coccidia antigen delivery vehicle and represents a new type of coccidiosis vaccines. In addition, this model could potentially be used in the development of malaria live sporozoite vaccines, in which antigens from different strains can be expressed in the vaccine strain. PMID:29375584

A Novel Vaccine Delivery Model of the Apicomplexan Eimeria tenella Expressing Eimeria maxima Antigen Protects Chickens against Infection of the Two Parasites.

PubMed

Tang, Xinming; Liu, Xianyong; Yin, Guangwen; Suo, Jingxia; Tao, Geru; Zhang, Sixin; Suo, Xun

2017-01-01

Vaccine delivery is critical in antigen discovery and vaccine efficacy and safety. The diversity of infectious diseases in humans and livestock has required the development of varied delivery vehicles to target different pathogens. In livestock animals, previous strategies for the development of coccidiosis vaccines have encountered several hurdles, limiting the development of multiple species vaccine formulations. Here, we describe a novel vaccine delivery system using transgenic Eimeria tenella expressing immunodominant antigens of Eimeria maxima . In this delivery system, the immune mapped protein 1 of E. maxima (EmIMP1) was delivered by the closely related species of E. tenella to the host immune system during the whole endogenous life cycle. The overexpression of the exogenous antigen did not interfere with the reproduction and immunogenicity of transgenic Eimeria . After immunization with the transgenic parasite, we detected EmIMP1's and E. maxima oocyst antigens' specific humoral and cellular immune responses. In particular, we observed partial protection of chickens immunized with transgenic E. tenella against subsequent E. maxima infections. Our results demonstrate that the transgenic Eimeria parasite is an ideal coccidia antigen delivery vehicle and represents a new type of coccidiosis vaccines. In addition, this model could potentially be used in the development of malaria live sporozoite vaccines, in which antigens from different strains can be expressed in the vaccine strain.

Coated microneedle arrays for transcutaneous delivery of live virus vaccines

PubMed Central

Vrdoljak, Anto; McGrath, Marie G.; Carey, John B.; Draper, Simon J.; Hill, Adrian V.S.; O’Mahony, Conor; Crean, Abina M.; Moore, Anne C.

2016-01-01

Vaccines are sensitive biologics that require continuous refrigerated storage to maintain their viability. The vast majority of vaccines are also administered using needles and syringes. The need for cold chain storage and the significant logistics surrounding needle-and-syringe vaccination is constraining the success of immunization programs. Recombinant live viral vectors are a promising platform for the development of vaccines against a number of infectious diseases, however these viruses must retain infectivity to be effective. Microneedles offer an effective and painless method for delivery of vaccines directly into skin that in the future could provide solutions to current vaccination issues. Here we investigated methods of coating live recombinant adenovirus and modified vaccinia virus Ankara (MVA) vectors onto solid microneedle arrays. An effective spray-coating method, using conventional pharmaceutical processes, was developed, in tandem with suitable sugar-based formulations, which produces arrays with a unique coating of viable virus in a dry form around the shaft of each microneedle on the array. Administration of live virus-coated microneedle arrays successfully resulted in virus delivery, transcutaneous infection and induced an antibody or CD8+ T cell response in mice that was comparable to that obtained by needle-and-syringe intradermal immunization. To our knowledge, this is the first report of successful vaccination with recombinant live viral vectored vaccines coated on microneedle delivery devices. PMID:22245683

Coated microneedle arrays for transcutaneous delivery of live virus vaccines.

PubMed

Vrdoljak, Anto; McGrath, Marie G; Carey, John B; Draper, Simon J; Hill, Adrian V S; O'Mahony, Conor; Crean, Abina M; Moore, Anne C

2012-04-10

Vaccines are sensitive biologics that require continuous refrigerated storage to maintain their viability. The vast majority of vaccines are also administered using needles and syringes. The need for cold chain storage and the significant logistics surrounding needle-and-syringe vaccination is constraining the success of immunization programs. Recombinant live viral vectors are a promising platform for the development of vaccines against a number of infectious diseases, however these viruses must retain infectivity to be effective. Microneedles offer an effective and painless method for delivery of vaccines directly into skin that in the future could provide solutions to current vaccination issues. Here we investigated methods of coating live recombinant adenovirus and modified vaccinia virus Ankara (MVA) vectors onto solid microneedle arrays. An effective spray-coating method, using conventional pharmaceutical processes, was developed, in tandem with suitable sugar-based formulations, which produces arrays with a unique coating of viable virus in a dry form around the shaft of each microneedle on the array. Administration of live virus-coated microneedle arrays successfully resulted in virus delivery, transcutaneous infection and induced an antibody or CD8(+) T cell response in mice that was comparable to that obtained by needle-and-syringe intradermal immunization. To our knowledge, this is the first report of successful vaccination with recombinant live viral vectored vaccines coated on microneedle delivery devices. Copyright © 2011 Elsevier B.V. All rights reserved.

Exploitation of Langerhans cells for in vivo DNA vaccine delivery into the lymph nodes.

PubMed

Tőke, E R; Lőrincz, O; Csiszovszki, Z; Somogyi, E; Felföldi, G; Molnár, L; Szipőcs, R; Kolonics, A; Malissen, B; Lori, F; Trocio, J; Bakare, N; Horkay, F; Romani, N; Tripp, C H; Stoitzner, P; Lisziewicz, J

2014-06-01

There is no clinically available cancer immunotherapy that exploits Langerhans cells (LCs), the epidermal precursors of dendritic cells (DCs) that are the natural agent of antigen delivery. We developed a DNA formulation with a polymer and obtained synthetic 'pathogen-like' nanoparticles that preferentially targeted LCs in epidermal cultures. These nanoparticles applied topically under a patch-elicited robust immune responses in human subjects. To demonstrate the mechanism of action of this novel vaccination strategy in live animals, we assembled a high-resolution two-photon laser scanning-microscope. Nanoparticles applied on the native skin poorly penetrated and poorly induced LC motility. The combination of nanoparticle administration and skin treatment was essential both for efficient loading the vaccine into the epidermis and for potent activation of the LCs to migrate into the lymph nodes. LCs in the epidermis picked up nanoparticles and accumulated them in the nuclear region demonstrating an effective nuclear DNA delivery in vivo. Tissue distribution studies revealed that the majority of the DNA was targeted to the lymph nodes. Preclinical toxicity of the LC-targeting DNA vaccine was limited to mild and transient local erythema caused by the skin treatment. This novel, clinically proven LC-targeting DNA vaccine platform technology broadens the options on DC-targeting vaccines to generate therapeutic immunity against cancer.

Particulate delivery systems for vaccination against bioterrorism agents and emerging infectious pathogens

PubMed Central

Fan, Yuchen; Moon, James J.

2016-01-01

Bioterrorism agents that can be easily transmitted with high mortality rates and cause debilitating diseases pose major threats to national security and public health. The recent Ebola virus outbreak in West Africa and ongoing Zika virus outbreak in Brazil, now spreading throughout Latin America, are case examples of emerging infectious pathogens that have incited widespread fear and economic and social disruption on a global scale. Prophylactic vaccines would provide effective countermeasures against infectious pathogens and biological warfare agents. However, traditional approaches relying on attenuated or inactivated vaccines have been hampered by their unacceptable levels of reactogenicity and safety issues, whereas subunit antigen-based vaccines suffer from suboptimal immunogenicity and efficacy. In contrast, particulate vaccine delivery systems offer key advantages, including efficient and stable delivery of subunit antigens, co-delivery of adjuvant molecules to bolster immune responses, low reactogenicity due to the use of biocompatible biomaterials, and robust efficiency to elicit humoral and cellular immunity in systemic and mucosal tissues. Thus, vaccine nanoparticles and microparticles are promising platforms for clinical development of biodefense vaccines. In this review, we summarize the current status of research efforts to develop particulate vaccine delivery systems against bioterrorism agents and emerging infectious pathogens. PMID:27038091

Influenza vaccine delivery delays from the perspective of primary care physicians.

PubMed

O'Leary, Sean T; Barrow, Jennifer C; McQuillan, Lon; Daley, Matthew F; Crane, Lori A; Beaty, Brenda L; Babbel, Christine I; Dickinson, L Miriam; Kempe, Allison

2011-06-01

The effects of delayed influenza vaccine delivery on primary practices are currently unknown. To describe, among primary care physicians nationally regarding the 2006-2007 influenza season: (1) how physicians defined influenza vaccine delay; (2) the extent of reported vaccine delays; and (3) the perceived effects of vaccine delays. Between March and June 2007, a total of 1268 primary care physicians nationally were surveyed. Survey response was 74% (n=940). The majority of physicians (79%) defined "influenza vaccine delay" as not receiving vaccine by November 1. Fifty-three percent reported a vaccine delay. Providers reported the following as effects of delays: reduced satisfaction of patients or parents in the practice (72%); decreased percentage in their practice who received the vaccination (65%); disruption of scheduling influenza clinics (55%); increased referral of patients elsewhere for vaccination (55%); and negative financial impact caused by unused vaccine (46%). Those who reported experiencing delays more often reported not meeting demand for vaccine (adjusted risk ratio [ARR]=1.83, 95% CI=1.64, 2.07); that grocery stores, retail outlets, or pharmacies had vaccine before their practices did (ARR=1.82, 95% CI=1.53, 2.26); not receiving all vaccine that was ordered (ARR=1.19, 95% CI=1.06, 1.36); and having leftover vaccine (ARR=1.17, 95% CI=1.04, 1.32). During the 2006-2007 influenza season, a non-shortage season, the majority of respondents reported experiencing an influenza vaccine delivery delay. Experiencing a delay was thought to decrease vaccination use, increase referrals elsewhere, and have a negative financial impact on practices. Delayed delivery of influenza vaccine is disruptive for primary care practices, and it consequently may affect vaccination coverage. Copyright © 2011 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Stable Dry Powder Formulation for Nasal Delivery of Anthrax Vaccine

PubMed Central

Wang, Sheena H.; Kirwan, Shaun M.; Abraham, Soman N.; Staats, Herman F.; Hickey, Anthony J.

2013-01-01

There is a current biodefense interest in protection against Anthrax. Here we developed a new generation of stable and effective anthrax vaccine. We studied the immune response elicited by rPA delivered intranasally with a novel mucosal adjuvant, a mast cell activator Compound 48/80. The vaccine formulation was prepared in a powder form by spray-freeze-drying (SFD) under optimized conditions to produce particles with a target size of D50=25μm, suitable for delivery to the rabbit nasal cavity. Physicochemical properties of the powder vaccines were characterized to assess their delivery and storage potential. Structural stability of rPA was confirmed by CD and ATR-FTIR, while functional stability of rPA and C48/80 was monitored by cell-based assays. Animal study was performed using a unitdose powder device for direct nasal application. Results showed that C48/80 provided effective mucosal adjuvant activity in rabbits. Freshly prepared SFD powder vaccine formulations or powders stored for over two years at room temperature elicited significantly elevated serum PA-specific and lethal toxin neutralization antibody titers that were comparable to that induced by IM immunization with rPA. Nasal delivery of this vaccine formulation may be a viable alternative to the currently licensed vaccine, or an attractive vaccine platform for other mucosally transmitted diseases. PMID:21905034

Delivery of Vaccines By Biodegradable Polymeric Microcapsules with Bioadherence Properties. Phase 1.

DTIC Science & Technology

1995-10-01

DAMD17-95-C-5061 TITLE: Delivery of Vaccines by Biodegradable Polymeric Microcapsules with Bioadherence Properties PRINCIPAL INVESTIGATOR: Robert L...SUBTITLE 5. FUNDING NUMBERS Delivery of Vaccines By Biodegradable Polymeric Microcapsules with Bioadherence Properties DAMD17-95-C-5061 6. AUTHOR(S...SUBJECT TERMS 15. NUMBER OF PAGES Polymer microspheres 27 Microencapsulated vaccines 16. PRICE CODE 17. SECURITY CLASSIFICATION 18. SECURITY

Perspective on Global Measles Epidemiology and Control and the Role of Novel Vaccination Strategies.

PubMed

Coughlin, Melissa M; Beck, Andrew S; Bankamp, Bettina; Rota, Paul A

2017-01-19

Measles is a highly contagious, vaccine preventable disease. Measles results in a systemic illness which causes profound immunosuppression often leading to severe complications. In 2010, the World Health Assembly declared that measles can and should be eradicated. Measles has been eliminated in the Region of the Americas, and the remaining five regions of the World Health Organization (WHO) have adopted measles elimination goals. Significant progress has been made through increased global coverage of first and second doses of measles-containing vaccine, leading to a decrease in global incidence of measles, and through improved case based surveillance supported by the WHO Global Measles and Rubella Laboratory Network. Improved vaccine delivery methods will likely play an important role in achieving measles elimination goals as these delivery methods circumvent many of the logistic issues associated with subcutaneous injection. This review highlights the status of global measles epidemiology, novel measles vaccination strategies, and describes the pathway toward measles elimination.

Perspective on Global Measles Epidemiology and Control and the Role of Novel Vaccination Strategies

PubMed Central

Coughlin, Melissa M.; Beck, Andrew S.; Bankamp, Bettina; Rota, Paul A.

2017-01-01

Measles is a highly contagious, vaccine preventable disease. Measles results in a systemic illness which causes profound immunosuppression often leading to severe complications. In 2010, the World Health Assembly declared that measles can and should be eradicated. Measles has been eliminated in the Region of the Americas, and the remaining five regions of the World Health Organization (WHO) have adopted measles elimination goals. Significant progress has been made through increased global coverage of first and second doses of measles-containing vaccine, leading to a decrease in global incidence of measles, and through improved case based surveillance supported by the WHO Global Measles and Rubella Laboratory Network. Improved vaccine delivery methods will likely play an important role in achieving measles elimination goals as these delivery methods circumvent many of the logistic issues associated with subcutaneous injection. This review highlights the status of global measles epidemiology, novel measles vaccination strategies, and describes the pathway toward measles elimination. PMID:28106841

Formulation and delivery of vaccines: Ongoing challenges for animal management

PubMed Central

Sharma, Sameer; Hinds, Lyn A.

2012-01-01

Development of a commercially successful animal vaccine is not only influenced by various immunological factors, such as type of antigen but also by formulation and delivery aspects. The latter includes the need for a vector or specific delivery system, the choice of route of administration and the nature of the target animal population and their habitat. This review describes the formulation and delivery aspects of various types of antigens such as killed microorganisms, proteins and nucleic acids for the development of efficacious and safe animal vaccines. It also focuses on the challenges associated with the different approaches that might be required for formulating and delivering species specific vaccines, particularly if their intended use is for improved animal management with respect to disease and/or reproductive control. PMID:23248557

Delivery cost of human papillomavirus vaccination of young adolescent girls in Peru, Uganda and Viet Nam.

PubMed

Levin, Carol E; Van Minh, Hoang; Odaga, John; Rout, Swampa Sarit; Ngoc, Diep Nguyen Thi; Menezes, Lysander; Araujo, Maria Ana Mendoza; LaMontagne, D Scott

2013-08-01

To estimate the incremental delivery cost of human papillomavirus (HPV) vaccination of young adolescent girls in Peru, Uganda and Viet Nam. Data were collected from a sample of facilities that participated in five demonstration projects for hpv vaccine delivery: school-based delivery was used in Peru, Uganda and Viet Nam; health-centre-based delivery was also used in Viet Nam; and integrated delivery, which involved existing health services, was also used in Uganda. Microcosting methods were used to guide data collection on the use of resources (i.e. staff, supplies and equipment) and data were obtained from government, demonstration project and health centre administrative records. Delivery costs were expressed in 2009 United States dollars (US$). Exclusively project-related expenses and the cost of the vaccine were excluded. The economic delivery cost per vaccine dose ranged from US$ 1.44 for integrated outreach in Uganda to US$ 3.88 for school-based delivery in Peru. In Viet Nam, the lowest cost per dose was US$ 1.92 for health-centre-based delivery. Cost profiles revealed that, in general, the largest contributing factors were project start-up costs and recurrent personnel costs. The delivery cost of HPV vaccine was higher than published costs for traditional vaccines recommended by the Expanded Programme on Immunization (EPI). The cost of delivering HPV vaccine to young adolescent girls in Peru, Uganda and Viet Nam was higher than that for vaccines currently in the EPI schedule. The cost per vaccine dose was lower when delivery was integrated into existing health services.

[Benefit-risk assessment of vaccination strategies].

PubMed

Hanslik, Thomas; Boëlle, Pierre Yves

2007-04-01

This article summarises the various stages of the risk/benefit assessment of vaccination strategies. Establishing the awaited effectiveness of a vaccination strategy supposes to have an epidemiologic description of the disease to be prevented. The effectiveness of the vaccine strategy will be thus expressed in numbers of cases, hospitalizations or deaths avoided. The effectiveness can be direct, expressed as the reduction of the incidence of the infectious disease in the vaccinated subjects compared to unvaccinated subjects. It can also be indirect, the unvaccinated persons being protected by the suspension in circulation of the pathogenic agent, consecutive to the implementation of the vaccination campaign. The risks of vaccination related to the adverse effects detected during the clinical trials preceding marketing are well quantified, but other risks can occur after marketing: e.g., serious and unexpected adverse effects detected by vaccinovigilance systems, or risk of increase in the age of cases if the vaccination coverage is insufficient. The medico-economic evaluation forms a part of the risks/benefit assessment, by positioning the vaccine strategy comparatively with other interventions for health. Epidemiologic and vaccinovigilance informations must be updated very regularly, which underlines the need for having an operational and reliable real time monitoring system to accompany the vaccination strategies. Lastly, in the context of uncertainty which often accompanies the risks/benefit assessments, it is important that an adapted communication towards the public and the doctors is planned.

Stable dry powder formulation for nasal delivery of anthrax vaccine.

PubMed

Wang, Sheena H; Kirwan, Shaun M; Abraham, Soman N; Staats, Herman F; Hickey, Anthony J

2012-01-01

There is a current biodefense interest in protection against anthrax. Here, we developed a new generation of stable and effective anthrax vaccine. We studied the immune response elicited by recombinant protective antigen (rPA) delivered intranasally with a novel mucosal adjuvant, a mast cell activator compound 48/80 (C48/80). The vaccine formulation was prepared in a powder form by spray-freeze-drying (SFD) under optimized conditions to produce particles with a target size of D(50) = 25 μm, suitable for delivery to the rabbit nasal cavity. Physicochemical properties of the powder vaccines were characterized to assess their delivery and storage potential. Structural stability of rPA was confirmed by circular dichroism and attenuated total reflectance-Fourier transform infrared spectroscopy, whereas functional stability of rPA and C48/80 was monitored by cell-based assays. Animal study was performed using a unit-dose powder device for direct nasal application. Results showed that C48/80 provided effective mucosal adjuvant activity in rabbits. Freshly prepared SFD powder vaccine formulations or powders stored for over 2 years at room temperature elicited significantly elevated serum PA-specific and lethal toxin neutralization antibody titers that were comparable to that induced by intramuscular immunization with rPA. Nasal delivery of this vaccine formulation may be a viable alternative to the currently licensed vaccine or an attractive vaccine platform for other mucosally transmitted diseases. Copyright © 2011 Wiley-Liss, Inc.

Stabilization of Influenza Vaccine Enhances Protection by Microneedle Delivery in the Mouse Skin

PubMed Central

Yoo, Dae-Goon; Compans, Richard W.; Prausnitz, Mark R.; Kang, Sang-Moo

2009-01-01

Background Simple and effective vaccine administration is particularly important for annually recommended influenza vaccination. We hypothesized that vaccine delivery to the skin using a patch containing vaccine-coated microneedles could be an attractive approach to improve influenza vaccination compliance and efficacy. Methodology/Principal Findings Solid microneedle arrays coated with inactivated influenza vaccine were prepared for simple vaccine delivery to the skin. However, the stability of the influenza vaccine, as measured by hemagglutination activity, was found to be significantly damaged during microneedle coating. The addition of trehalose to the microneedle coating formulation retained hemagglutination activity, indicating stabilization of the coated influenza vaccine. For both intramuscular and microneedle skin immunization, delivery of un-stabilized vaccine yielded weaker protective immune responses including viral neutralizing antibodies, protective efficacies, and recall immune responses to influenza virus. Immunization using un-stabilized vaccine also shifted the pattern of antibody isotypes compared to the stabilized vaccine. Importantly, a single microneedle-based vaccination using stabilized influenza vaccine was found to be superior to intramuscular immunization in controlling virus replication as well as in inducing rapid recall immune responses post challenge. Conclusions/Significance The functional integrity of hemagglutinin is associated with inducing improved protective immunity against influenza. Simple microneedle influenza vaccination in the skin produced superior protection compared to conventional intramuscular immunization. This approach is likely to be applicable to other vaccines too. PMID:19779615

Smart delivery of vaccines

NASA Astrophysics Data System (ADS)

Melief, Cornelis J. M.

2018-06-01

A strategy to enhance antigen immunogenicity was developed by adsorption of polyethyleneimine on a mesoporous silica microrod vaccine for the presentation of tumour viruses and neoantigens, demonstrating their ability to drive anti-tumour immunity.

Delivery cost of human papillomavirus vaccination of young adolescent girls in Peru, Uganda and Viet Nam

PubMed Central

Van Minh, Hoang; Odaga, John; Rout, Swampa Sarit; Ngoc, Diep Nguyen Thi; Menezes, Lysander; Araujo, Maria Ana Mendoza; LaMontagne, D Scott

2013-01-01

Abstract Objective To estimate the incremental delivery cost of human papillomavirus (HPV) vaccination of young adolescent girls in Peru, Uganda and Viet Nam. Methods Data were collected from a sample of facilities that participated in five demonstration projects for HPV vaccine delivery: school-based delivery was used in Peru, Uganda and Viet Nam; health-centre-based delivery was also used in Viet Nam; and integrated delivery, which involved existing health services, was also used in Uganda. Microcosting methods were used to guide data collection on the use of resources (i.e. staff, supplies and equipment) and data were obtained from government, demonstration project and health centre administrative records. Delivery costs were expressed in 2009 United States dollars (US$). Exclusively project-related expenses and the cost of the vaccine were excluded. Findings The economic delivery cost per vaccine dose ranged from US$ 1.44 for integrated outreach in Uganda to US$ 3.88 for school-based delivery in Peru. In Viet Nam, the lowest cost per dose was US$ 1.92 for health-centre-based delivery. Cost profiles revealed that, in general, the largest contributing factors were project start-up costs and recurrent personnel costs. The delivery cost of HPV vaccine was higher than published costs for traditional vaccines recommended by the Expanded Programme on Immunization (EPI). Conclusion The cost of delivering HPV vaccine to young adolescent girls in Peru, Uganda and Viet Nam was higher than that for vaccines currently in the EPI schedule. The cost per vaccine dose was lower when delivery was integrated into existing health services. PMID:23940406

Engineered hybrid spider silk particles as delivery system for peptide vaccines.

PubMed

Lucke, Matthias; Mottas, Inès; Herbst, Tina; Hotz, Christian; Römer, Lin; Schierling, Martina; Herold, Heike M; Slotta, Ute; Spinetti, Thibaud; Scheibel, Thomas; Winter, Gerhard; Bourquin, Carole; Engert, Julia

2018-07-01

The generation of strong T-cell immunity is one of the main challenges for the development of successful vaccines against cancer and major infectious diseases. Here we have engineered spider silk particles as delivery system for a peptide-based vaccination that leads to effective priming of cytotoxic T-cells. The recombinant spider silk protein eADF4(C16) was fused to the antigenic peptide from ovalbumin, either without linker or with a cathepsin cleavable peptide linker. Particles prepared from the hybrid proteins were taken up by dendritic cells, which are essential for T-cell priming, and successfully activated cytotoxic T-cells, without signs of immunotoxicity or unspecific immunostimulatory activity. Upon subcutaneous injection in mice, the particles were taken up by dendritic cells and accumulated in the lymph nodes, where immune responses are generated. Particles from hybrid proteins containing a cathepsin-cleavable linker induced a strong antigen-specific proliferation of cytotoxic T-cells in vivo, even in the absence of a vaccine adjuvant. We thus demonstrate the efficacy of a new vaccine strategy using a protein-based all-in-one vaccination system, where spider silk particles serve as carriers with an incorporated peptide antigen. Our study further suggests that engineered spider silk-based vaccines are extremely stable, easy to manufacture, and readily customizable. Copyright © 2018 Elsevier Ltd. All rights reserved.

The growth of retail clinics in vaccination delivery in the U.S.

PubMed

Uscher-Pines, Lori; Harris, Katherine M; Burns, Rachel M; Mehrotra, Ateev

2012-07-01

Retail clinics are a promising venue in which to promote and administer vaccinations; however, little is known about who receives vaccinations at a retail clinic. The aim of this paper was to describe the use of retail clinics in the delivery of recommended vaccinations. The three largest retail clinic operators in the U.S.--MinuteClinic, TakeCare, and LittleClinic--provided de-identified clinic data for 2007-2009. Descriptive statistics were generated in 2011 on visit type, type of vaccination, patient age, and payment method. From 2007 to 2009, there were 8.9 million retail clinic visits across the three largest clinic operators. In 2009, vaccinations were administered at 1,952,610 visits, up from 469,330 visits in 2007. Visits in which vaccinations were administered accounted for 39.9%, 36.4%, and 42.0% of total visits in 2007, 2008, and 2009, respectively. In 2009, 1.8 million influenza vaccinations (including seasonal and H1N1 vaccinations) were administered by the two largest retail clinic operators (94% of all vaccination visits). Pneumococcal vaccination was administered at 59,849 visits (3% of all vaccination visits). In 2009, vaccinations were also administered in 0.8% of acute care visits (n=18,807); 0.8% of chronic care visits (n=261); and 1.3% of general medical exams (n=2497). Results suggest that retail clinics play a growing role in vaccination delivery, and vaccinations constitute a substantial share of the business conducted by retail clinics. As such, retail clinics have the potential to play an important role in vaccination delivery in the U.S. Retail clinics potentially could deliver more vaccinations if they reviewed vaccination histories and counseled patients regarding the benefits of vaccination during acute care visits. Copyright © 2012 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Human and Animal Vaccination Delivery to Remote Nomadic Families, Chad

PubMed Central

Bechir, Mahamat; Ahmed, Mahamat Abdoulaye; Wyss, Kaspar; Randolph, Thomas F.; Zinsstag, Jakob

2007-01-01

Vaccination services for people and livestock often fail to achieve sufficient coverages in Africa’s remote rural settings because of financial, logistic, and service delivery constraints. In Chad from 2000 through 2005, we demonstrated the feasibility of combining vaccination programs for nomadic pastoralists and their livestock. Sharing of transport logistics and equipment between physicians and veterinarians reduced total costs. Joint delivery of human and animal health services is adapted to and highly valued by hard-to-reach pastoralists. In intervention zones, for the first time ≈10% of nomadic children (>1–11 months of age) were fully immunized annually and more children and women were vaccinated per day during joint vaccination rounds than during vaccination of persons only and not their livestock (130 vs. 100, p<0.001). By optimizing use of limited logistical and human resources, public health and veterinary services both become more effective, especially at the district level. PMID:17552089

Seasonal influenza vaccination delivery through community pharmacists in England: evaluation of the London pilot

PubMed Central

Atkins, Katherine; van Hoek, Albert Jan; Watson, Conall; Baguelin, Marc; Choga, Lethiwe; Patel, Anika; Raj, Thara; Jit, Mark; Griffiths, Ulla

2016-01-01

Objective To evaluate the effectiveness and cost of the pan-London pharmacy initiative, a programme that allows administration of seasonal influenza vaccination to eligible patients at pharmacies. Design We analysed 2013–2015 data on vaccination uptake in pharmacies via the Sonar reporting system, and the total vaccination uptake via 2011–2015 ImmForm general practitioner (GP) reporting system data. We conducted an online survey of London pharmacists who participate in the programme to assess time use data, vaccine choice, investment costs and opinions about the programme. We conducted an online survey of London GPs to assess vaccine choice of vaccine and opinions about the pharmacy vaccine delivery programme. Setting All London boroughs. Participants London-based GPs, and pharmacies that currently offer seasonal flu vaccination. Interventions Not applicable. Main outcome measures Comparison of annual vaccine uptake in London across risk groups from years before pharmacy vaccination introduction to after pharmacy vaccination introduction. Completeness of vaccine uptake reporting data. Cost to the National Health Service (NHS) of flu vaccine delivery at pharmacies with that at GPs. Cost to pharmacists of flu delivery. Opinions of pharmacists and GPs regarding the flu vaccine pharmacy initiative. Results No significant change in the uptake of seasonal vaccination in any of the risk groups as a result of the pharmacy initiative. While on average a pharmacy-administered flu vaccine dose costs the NHS up to £2.35 less than a dose administered at a GP, a comparison of the 2 recording systems suggests there is substantial loss of data. Conclusions Flu vaccine delivery through pharmacies shows potential for improving convenience for vaccine recipients. However, there is no evidence that vaccination uptake increases and the use of 2 separate recording systems leads to time-consuming data entry and missing vaccine record data. PMID:26883237

Vaccine Adjuvant Incorporation Strategy Dictates Peptide Amphiphile Micelle Immunostimulatory Capacity.

PubMed

Zhang, Rui; Kramer, Jake S; Smith, Josiah D; Allen, Brittany N; Leeper, Caitlin N; Li, Xiaolei; Morton, Logan D; Gallazzi, Fabio; Ulery, Bret D

2018-06-01

Current vaccine research has shifted from traditional vaccines (i.e., whole-killed or live-attenuated) to subunit vaccines (i.e., protein, peptide, or DNA) as the latter is much safer due to delivering only the bioactive components necessary to produce a desirable immune response. Unfortunately, subunit vaccines are very weak immunogens requiring delivery vehicles and the addition of immunostimulatory molecules termed adjuvants to convey protective immunity. An interesting type of delivery vehicle is peptide amphiphile micelles (PAMs), unique biomaterials where the vaccine is part of the nanomaterial itself. Due to the modularity of PAMs, they can be readily modified to deliver both vaccine antigens and adjuvants within a singular construct. Through the co-delivery of a model antigenic epitope (Ovalbumin 319-340 -OVA BT ) and a known molecular adjuvant (e.g., 2,3-dipalmitoyl-S-glyceryl cysteine-Pam 2 C), greater insight into the mechanisms by which PAMs can exert immunostimulatory effects was gained. It was found that specific combinations of antigen and adjuvant can significantly alter vaccine immunogenicity both in vitro and in vivo. These results inform fundamental design rules that can be leveraged to fabricate optimal PAM-based vaccine formulations for future disease-specific applications. Graphical Abstract.

Anthrax vaccination strategies

PubMed Central

Cybulski, Robert J.; Sanz, Patrick; O'Brien, Alison D.

2009-01-01

The biological attack conducted through the U.S. postal system in 2001 broadened the threat posed by anthrax from one pertinent mainly to soldiers on the battlefield to one understood to exist throughout our society. The expansion of the threatened population placed greater emphasis on the reexamination of how we vaccinate against Bacillus anthracis. The currently-licensed Anthrax Vaccine, Adsorbed (AVA) and Anthrax Vaccine, Precipitated (AVP) are capable of generating a protective immune response but are hampered by shortcomings that make their widespread use undesirable or infeasible. Efforts to gain U.S. Food and Drug Administration (FDA) approval for licensure of a second generation recombinant protective antigen (rPA)-based anthrax vaccine are ongoing. However, this vaccine's reliance on the generation of a humoral immune response against a single virulence factor has led a number of scientists to conclude that the vaccine is likely not the final solution to optimal anthrax vaccine design. Other vaccine approaches, which seek a more comprehensive immune response targeted at multiple components of the B. anthracis organism, are under active investigation. This review seeks to summarize work that has been done to build on the current PA-based vaccine methodology and to evaluate the search for future anthrax prophylaxis strategies. PMID:19729034

Polymeric nanoparticles: potent vectors for vaccine delivery targeting cancer and infectious diseases.

PubMed

Bolhassani, Azam; Javanzad, Shabnam; Saleh, Tayebeh; Hashemi, Mehrdad; Aghasadeghi, Mohammad Reza; Sadat, Seyed Mehdi

2014-01-01

Nanocarriers with various compositions and biological properties have been extensively applied for in vitro/in vivo drug and gene delivery. The family of nanocarriers includes polymeric nanoparticles, lipid-based carriers (liposomes/micelles), dendrimers, carbon nanotubes, and gold nanoparticles (nanoshells/nanocages). Among different delivery systems, polymeric carriers have several properties such as: easy to synthesize, inexpensive, biocompatible, biodegradable, non-immunogenic, non-toxic, and water soluble. In addition, cationic polymers seem to produce more stable complexes led to a more protection during cellular trafficking than cationic lipids. Nanoparticles often show significant adjuvant effects in vaccine delivery since they may be easily taken up by antigen presenting cells (APCs). Natural polymers such as polysaccharides and synthetic polymers have demonstrated great potential to form vaccine nanoparticles. The development of new adjuvants or delivery systems for DNA and protein immunization is an expanding research field. This review describes polymeric carriers especially PLGA, chitosan, and PEI as vaccine delivery systems.

A case study using the United Republic of Tanzania: costing nationwide HPV vaccine delivery using the WHO Cervical Cancer Prevention and Control Costing Tool.

PubMed

Hutubessy, Raymond; Levin, Ann; Wang, Susan; Morgan, Winthrop; Ally, Mariam; John, Theopista; Broutet, Nathalie

2012-11-13

The purpose, methods, data sources and assumptions behind the World Health Organization (WHO) Cervical Cancer Prevention and Control Costing (C4P) tool that was developed to assist low- and middle-income countries (LMICs) with planning and costing their nationwide human papillomavirus (HPV) vaccination program are presented. Tanzania is presented as a case study where the WHO C4P tool was used to cost and plan the roll-out of HPV vaccines nationwide as part of the national comprehensive cervical cancer prevention and control strategy. The WHO C4P tool focuses on estimating the incremental costs to the health system of vaccinating adolescent girls through school-, health facility- and/or outreach-based strategies. No costs to the user (school girls, parents or caregivers) are included. Both financial (or costs to the Ministry of Health) and economic costs are estimated. The cost components for service delivery include training, vaccination (health personnel time and transport, stationery for tally sheets and vaccination cards, and so on), social mobilization/IEC (information, education and communication), supervision, and monitoring and evaluation (M&E). The costs of all the resources used for HPV vaccination are totaled and shown with and without the estimated cost of the vaccine. The total cost is also divided by the number of doses administered and number of fully immunized girls (FIGs) to estimate the cost per dose and cost per FIG. Over five years (2011 to 2015), the cost of establishing an HPV vaccine program that delivers three doses of vaccine to girls at schools via phased national introduction (three regions in year 1, ten regions in year 2 and all 26 regions in years 3 to 5) in Tanzania is estimated to be US$9.2 million (excluding vaccine costs) and US$31.5 million (with vaccine) assuming a vaccine price of US$5 (GAVI 2011, formerly the Global Alliance for Vaccines and Immunizations). This is equivalent to a financial cost of US$5.77 per FIG, excluding

A case study using the United Republic of Tanzania: costing nationwide HPV vaccine delivery using the WHO Cervical Cancer Prevention and Control Costing Tool

PubMed Central

2012-01-01

Background The purpose, methods, data sources and assumptions behind the World Health Organization (WHO) Cervical Cancer Prevention and Control Costing (C4P) tool that was developed to assist low- and middle-income countries (LMICs) with planning and costing their nationwide human papillomavirus (HPV) vaccination program are presented. Tanzania is presented as a case study where the WHO C4P tool was used to cost and plan the roll-out of HPV vaccines nationwide as part of the national comprehensive cervical cancer prevention and control strategy. Methods The WHO C4P tool focuses on estimating the incremental costs to the health system of vaccinating adolescent girls through school-, health facility- and/or outreach-based strategies. No costs to the user (school girls, parents or caregivers) are included. Both financial (or costs to the Ministry of Health) and economic costs are estimated. The cost components for service delivery include training, vaccination (health personnel time and transport, stationery for tally sheets and vaccination cards, and so on), social mobilization/IEC (information, education and communication), supervision, and monitoring and evaluation (M&E). The costs of all the resources used for HPV vaccination are totaled and shown with and without the estimated cost of the vaccine. The total cost is also divided by the number of doses administered and number of fully immunized girls (FIGs) to estimate the cost per dose and cost per FIG. Results Over five years (2011 to 2015), the cost of establishing an HPV vaccine program that delivers three doses of vaccine to girls at schools via phased national introduction (three regions in year 1, ten regions in year 2 and all 26 regions in years 3 to 5) in Tanzania is estimated to be US$9.2 million (excluding vaccine costs) and US$31.5 million (with vaccine) assuming a vaccine price of US$5 (GAVI 2011, formerly the Global Alliance for Vaccines and Immunizations). This is equivalent to a financial cost of US

Delivery cost analysis of a reactive mass cholera vaccination campaign: a case study of Shanchol™ vaccine use in Lake Chilwa, Malawi.

PubMed

Ilboudo, Patrick G; Le Gargasson, Jean-Bernard

2017-12-19

Cholera is a diarrheal disease that produces rapid dehydration. The infection is a significant cause of mortality and morbidity. Oral cholera vaccine (OCV) has been propagated for the prevention of cholera. Evidence on OCV delivery cost is insufficient in the African context. This study aims to analyze Shanchol vaccine delivery costs, focusing on the vaccination campaign in response of a cholera outbreak in Lake Chilwa, Malawi. The vaccination campaign was implemented in two rounds in February and March 2016. Structured questionnaires were used to collect costs incurred for each vaccination related activity, including vaccine procurement and shipment, training, microplanning, sensitization, social mobilization and vaccination rounds. Costs collected, including financial and economic costs were analyzed using Choltool, a standardized cholera cost calculator. In total, 67,240 persons received two complete doses of the vaccine. Vaccine coverage was higher in the first round than in the second. The two-dose coverage measured with the immunization card was estimated at 58%. The total financial cost incurred in implementing the campaign was US$480275 while the economic cost was US$588637. The total financial and economic costs per fully vaccinated person were US$7.14 and US$8.75, respectively, with delivery costs amounting to US$1.94 and US$3.55, respectively. Vaccine procurement and shipment accounted respectively for 73% and 59% of total financial and economic costs of the total vaccination campaign costs while the incurred personnel cost accounted for 13% and 29% of total financial and economic costs. Cost for delivering a single dose of Shanchol was estimated at US$0.97. This study provides new evidence on economic and financial costs of a reactive campaign implemented by international partners in collaboration with MoH. It shows that involvement of international partners' personnel may represent a substantial share of campaign's costs, affecting unit and vaccine

Mucosal vaccines: a paradigm shift in the development of mucosal adjuvants and delivery vehicles.

PubMed

Srivastava, Atul; Gowda, Devegowda Vishakante; Madhunapantula, SubbaRao V; Shinde, Chetan G; Iyer, Meenakshi

2015-04-01

Mucosal immune responses are the first-line defensive mechanisms against a variety of infections. Therefore, immunizations of mucosal surfaces from which majority of infectious agents make their entry, helps to protect the body against infections. Hence, vaccinization of mucosal surfaces by using mucosal vaccines provides the basis for generating protective immunity both in the mucosal and systemic immune compartments. Mucosal vaccines offer several advantages over parenteral immunization. For example, (i) ease of administration; (ii) non-invasiveness; (iii) high-patient compliance; and (iv) suitability for mass vaccination. Despite these benefits, to date, only very few mucosal vaccines have been developed using whole microorganisms and approved for use in humans. This is due to various challenges associated with the development of an effective mucosal vaccine that can work against a variety of infections, and various problems concerned with the safe delivery of developed vaccine. For instance, protein antigen alone is not just sufficient enough for the optimal delivery of antigen(s) mucosally. Hence, efforts have been made to develop better prophylactic and therapeutic vaccines for improved mucosal Th1 and Th2 immune responses using an efficient and safe immunostimulatory molecule and novel delivery carriers. Therefore, in this review, we have made an attempt to cover the recent advancements in the development of adjuvants and delivery carriers for safe and effective mucosal vaccine production. © 2015 APMIS. Published by John Wiley & Sons Ltd.

Development of replication-competent viral vectors for HIV vaccine delivery

PubMed Central

Parks, Christopher L.; Picker, Louis J.; King, C. Richter

2014-01-01

Purpose of review Briefly describe some of the replication-competent (RC) vectors being investigated for development of candidate HIV vaccines focusing primarily on technologies that have advanced to testing in macaques or have entered clinical trials. Recent findings RC viral vectors have advanced to the stage were decisions can be made regarding future development of HIV vaccines. The viruses being used as RC vector platforms vary considerably, and their unique attributes make it possible to test multiple vaccine design concepts and also mimic various aspects of an HIV infection. RC viral vectors encoding SIV or HIV proteins can be used to safely immunize macaques, and in some cases, there is evidence of significant vaccine efficacy in challenge protection studies. Several live HIV vaccine vectors are in clinical trials to evaluate immunogenicity, safety, the effect of mucosal delivery, and potential effects of pre-existing immunity. Summary A variety of DNA and RNA viruses are being used to develop RC viral vectors for HIV vaccine delivery. Multiple viral vector platforms have proven to be safe and immunogenic with evidence of efficacy in macaques. Some of the more advanced HIV vaccine prototypes based on vesicular stomatitis virus, vaccinia virus, measles virus, and Sendai virus are in clinical trials. PMID:23925000

Administration of HPV DNA vaccine via electroporation elicits the strongest CD8+ T cell immune responses compared to intramuscular injection and intradermal gene gun delivery

PubMed Central

Best, Simon R.; Peng, Shiwen; Juang, Chi-Mou; Hung, Chien-Fu; Hannaman, Drew; Saunders, John R.; Wu, T.-C.; Pai, Sara I.

2009-01-01

DNA vaccines are an attractive approach to eliciting antigen-specific immunity. Intracellular targeting of tumor antigens through its linkage to immunostimulatory molecules such as calreticulin (CRT) can improve antigen processing and presentation through the MHC Class I pathway and increase cytotoxic CD8+ T cell production. However, even with these enhancements, the efficacy of such immunotherapeutic strategies is dependent on the identification of an effective route and method of DNA administration. Electroporation and gene gun-mediated particle delivery are leading methods of DNA vaccine delivery that can generate protective and therapeutic levels of immune responses in experimental models. In this study, we perform a head-to-head comparison of three methods of vaccination – conventional intramuscular injection, electroporation mediated intramuscular delivery, and epidermal gene gun-mediated particle delivery - in the ability to generate antigen specific cytotoxic CD8+ T cell responses as well as anti-tumor immune responses against an HPV-16 E7 expressing tumor cell line using the pNGVL4a-CRT/E7(detox) DNA vaccine. Vaccination via electroporation generated the highest number of E7-specific cytotoxic CD8+ T cells, which correlated to improved outcomes in the treatment of growing tumors. In addition, we demonstrate that electroporation results in significantly higher levels of circulating protein compared to gene gun or intramuscular vaccination, which likely enhances calreticulin’s role as a local tumor anti-angiogenesis agent. We conclude that electroporation is a promising method for delivery of HPV DNA vaccines and should be considered for DNA vaccine delivery in human clinical trials. PMID:19622402

Seasonal influenza vaccination delivery through community pharmacists in England: evaluation of the London pilot.

PubMed

Atkins, Katherine; van Hoek, Albert Jan; Watson, Conall; Baguelin, Marc; Choga, Lethiwe; Patel, Anika; Raj, Thara; Jit, Mark; Griffiths, Ulla

2016-02-16

To evaluate the effectiveness and cost of the pan-London pharmacy initiative, a programme that allows administration of seasonal influenza vaccination to eligible patients at pharmacies. We analysed 2013-2015 data on vaccination uptake in pharmacies via the Sonar reporting system, and the total vaccination uptake via 2011-2015 ImmForm general practitioner (GP) reporting system data. We conducted an online survey of London pharmacists who participate in the programme to assess time use data, vaccine choice, investment costs and opinions about the programme. We conducted an online survey of London GPs to assess vaccine choice of vaccine and opinions about the pharmacy vaccine delivery programme. All London boroughs. London-based GPs, and pharmacies that currently offer seasonal flu vaccination. Not applicable. Comparison of annual vaccine uptake in London across risk groups from years before pharmacy vaccination introduction to after pharmacy vaccination introduction. Completeness of vaccine uptake reporting data. Cost to the National Health Service (NHS) of flu vaccine delivery at pharmacies with that at GPs. Cost to pharmacists of flu delivery. Opinions of pharmacists and GPs regarding the flu vaccine pharmacy initiative. No significant change in the uptake of seasonal vaccination in any of the risk groups as a result of the pharmacy initiative. While on average a pharmacy-administered flu vaccine dose costs the NHS up to £2.35 less than a dose administered at a GP, a comparison of the 2 recording systems suggests there is substantial loss of data. Flu vaccine delivery through pharmacies shows potential for improving convenience for vaccine recipients. However, there is no evidence that vaccination uptake increases and the use of 2 separate recording systems leads to time-consuming data entry and missing vaccine record data. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Optimal vaccination strategies and rational behaviour in seasonal epidemics.

PubMed

Doutor, Paulo; Rodrigues, Paula; Soares, Maria do Céu; Chalub, Fabio A C C

2016-12-01

We consider a SIRS model with time dependent transmission rate. We assume time dependent vaccination which confers the same immunity as natural infection. We study two types of vaccination strategies: (i) optimal vaccination, in the sense that it minimizes the effort of vaccination in the set of vaccination strategies for which, for any sufficiently small perturbation of the disease free state, the number of infectious individuals is monotonically decreasing; (ii) Nash-equilibria strategies where all individuals simultaneously minimize the joint risk of vaccination versus the risk of the disease. The former case corresponds to an optimal solution for mandatory vaccinations, while the second corresponds to the equilibrium to be expected if vaccination is fully voluntary. We are able to show the existence of both optimal and Nash strategies in a general setting. In general, these strategies will not be functions but Radon measures. For specific forms of the transmission rate, we provide explicit formulas for the optimal and the Nash vaccination strategies.

Neonatal Vaccination: Challenges and Intervention Strategies.

PubMed

Morris, Matthew C; Surendran, Naveen

2016-01-01

While vaccines have been tremendously successful in reducing the incidence of serious infectious diseases, newborns remain particularly vulnerable in the first few months of their life to life-threatening infections. A number of challenges exist to neonatal vaccination. However, recent advances in the understanding of neonatal immunology offer insights to overcome many of those challenges. This review will present an overview of the features of neonatal immunity which make vaccination difficult, survey the mechanisms of action of available vaccine adjuvants with respect to the unique features of neonatal immunity, and propose a possible mechanism contributing to the inability of neonates to generate protective immune responses to vaccines. We surveyed recent published findings on the challenges to neonatal vaccination and possible intervention strategies including the use of novel vaccine adjuvants to develop efficacious neonatal vaccines. Challenges in the vaccination of neonates include interference from maternal antibody and excessive skewing towards Th2 immunity, which can be counteracted by the use of proper adjuvants. Synergistic stimulation of multiple Toll-like receptors by incorporating well-defined agonist-adjuvant combinations to vaccines is a promising strategy to ensure a protective vaccine response in neonates. © 2016 S. Karger AG, Basel.

pH-Responsive Nanoparticle Vaccines for Dual-Delivery of Antigens and Immunostimulatory Oligonucleotides

PubMed Central

Wilson, John T.; Keller, Salka; Manganiello, Matthew J.; Cheng, Connie; Lee, Chen-Chang; Opara, Chinonso; Convertine, Anthony; Stayton, Patrick S.

2013-01-01

Protein subunit vaccines offer important potential advantages over live vaccine vectors, but generally elicit weaker and shorter-lived cellular immune responses. Here we investigate the use of pH-responsive, endosomolytic polymer nanoparticles that were originally developed for RNA delivery as vaccine delivery vehicles for enhancing cellular and humoral immune responses. Micellar nanoparticles were assembled from amphiphilic diblock copolymers composed of an ampholytic core-forming block and a re-designed polycationic corona block doped with thiol-reactive pyridyl disulfide groups to enable dual-delivery of antigens and immunostimulatory CpG oligodeoxynucleotide (CpG ODN) adjuvants. Polymers assembled into 23 nm particles with simultaneous packaging of CpG ODN and a thiolated protein antigen, ovalbumin (ova). Conjugation of ova to nanoparticles significantly enhanced antigen cross-presentation in vitro relative to free ova or an unconjugated, physical mixture of the parent compounds. Subcutaneous vaccination of mice with ova-nanoparticle conjugates elicited a significantly higher CD8+ T cell response (0.5% IFN-ɣ+ of CD8+) compared to mice vaccinated with free ova or a physical mixture of the two components. Significantly, immunization with ova-nanoparticle conjugates electrostatically complexed with CpG ODN (dual-delivery) enhanced CD8+ T cell responses (3.4% IFN-ɣ+ of CD8+) 7-, 18-, and 8-fold relative to immunization with conjugates, ova administered with free CpG, or a formulation containing free ova and CpG complexed to micelles, respectively. Similarly, dual-delivery carriers significantly increased CD4+IFN-ɣ+ (Th1) responses, and elicited a balanced IgG1/IgG2c antibody response. Intradermal administration further augmented cellular immune responses, with dual-delivery carriers inducing ~7% antigen-specific CD8+ T cells. This work demonstrates the ability of pH-responsive, endosomolytic nanoparticles to actively promote antigen cross-presentation and

Vaccines and immunization strategies for dengue prevention

PubMed Central

Liu, Yang; Liu, Jianying; Cheng, Gong

2016-01-01

Dengue is currently the most significant arboviral disease afflicting tropical and sub-tropical countries worldwide. Dengue vaccines, such as the multivalent attenuated, chimeric, DNA and inactivated vaccines, have been developed to prevent dengue infection in humans, and they function predominantly by stimulating immune responses against the dengue virus (DENV) envelope (E) and nonstructural-1 proteins (NS1). Of these vaccines, a live attenuated chimeric tetravalent DENV vaccine developed by Sanofi Pasteur has been licensed in several countries. However, this vaccine renders only partial protection against the DENV2 infection and is associated with an unexplained increased incidence of hospitalization for severe dengue disease among children younger than nine years old. In addition to the virus-based vaccines, several mosquito-based dengue immunization strategies have been developed to interrupt the vector competence and effectively reduce the number of infected mosquito vectors, thus controlling the transmission of DENV in nature. Here we summarize the recent progress in the development of dengue vaccines and novel immunization strategies and propose some prospective vaccine strategies for disease prevention in the future. PMID:27436365

Optimization model of vaccination strategy for dengue transmission

NASA Astrophysics Data System (ADS)

Widayani, H.; Kallista, M.; Nuraini, N.; Sari, M. Y.

2014-02-01

Dengue fever is emerging tropical and subtropical disease caused by dengue virus infection. The vaccination should be done as a prevention of epidemic in population. The host-vector model are modified with consider a vaccination factor to prevent the occurrence of epidemic dengue in a population. An optimal vaccination strategy using non-linear objective function was proposed. The genetic algorithm programming techniques are combined with fourth-order Runge-Kutta method to construct the optimal vaccination. In this paper, the appropriate vaccination strategy by using the optimal minimum cost function which can reduce the number of epidemic was analyzed. The numerical simulation for some specific cases of vaccination strategy is shown.

Intranasal and sublingual delivery of inactivated polio vaccine.

PubMed

Kraan, Heleen; Soema, Peter; Amorij, Jean-Pierre; Kersten, Gideon

2017-05-09

Polio is on the brink of eradication. Improved inactivated polio vaccines (IPV) are needed towards complete eradication and for the use in the period thereafter. Vaccination via mucosal surfaces has important potential advantages over intramuscular injection using conventional needle and syringe, the currently used delivery method for IPV. One of them is the ability to induce both serum and mucosal immune responses: the latter may provide protection at the port of virus entry. The current study evaluated the possibilities of polio vaccination via mucosal surfaces using IPV based on attenuated Sabin strains. Mice received three immunizations with trivalent sIPV via intramuscular injection, or via the intranasal or sublingual route. The need of an adjuvant for the mucosal routes was investigated as well, by testing sIPV in combination with the mucosal adjuvant cholera toxin. Both intranasal and sublingual sIPV immunization induced systemic polio-specific serum IgG in mice that were functional as measured by poliovirus neutralization. Intranasal administration of sIPV plus adjuvant induced significant higher systemic poliovirus type 3 neutralizing antibody titers than sIPV delivered via the intramuscular route. Moreover, mucosal sIPV delivery elicited polio-specific IgA titers at different mucosal sites (IgA in saliva, fecal extracts and intestinal tissue) and IgA-producing B-cells in the spleen, where conventional intramuscular vaccination was unable to do so. However, it is likely that a mucosal adjuvant is required for sublingual vaccination. Further research on polio vaccination via sublingual mucosal route should include the search for safe and effective adjuvants, and the development of novel oral dosage forms that improve antigen uptake by oral mucosa, thereby increasing vaccine immunogenicity. This study indicates that both the intranasal and sublingual routes might be valuable approaches for use in routine vaccination or outbreak control in the period after

Mesoporous silica nanoparticles as antigen carriers and adjuvants for vaccine delivery

NASA Astrophysics Data System (ADS)

Mody, Karishma T.; Popat, Amirali; Mahony, Donna; Cavallaro, Antonino S.; Yu, Chengzhong; Mitter, Neena

2013-05-01

Vaccines have been at the forefront of improving human health for over two centuries. The challenges faced in developing effective vaccines flow from complexities associated with the immune system and requirement of an efficient and safe adjuvant to induce a strong adaptive immune response. Development of an efficient vaccine formulation requires careful selection of a potent antigen, efficient adjuvant and route of delivery. Adjuvants are immunological agents that activate the antigen presenting cells (APCs) and elicit a strong immune response. In the past decade, the use of mesoporous silica nanoparticles (MSNs) has gained significant attention as potential delivery vehicles for various biomolecules. In this review, we aim to highlight the potential of MSNs as vaccine delivery vehicles and their ability to act as adjuvants. We have provided an overview on the latest progress on synthesis, adsorption and release kinetics and biocompatibility of MSNs as next generation antigen carriers and adjuvants. A comprehensive summary on the ability of MSNs to deliver antigens and elicit both humoral and cellular immune responses is provided. Finally, we give insight on fundamental challenges and some future prospects of these nanoparticles as adjuvants.

Combinatorial evaluation of in vivo distribution of polyanhydride particle-based platforms for vaccine delivery

PubMed Central

Petersen, Latrisha K; Huntimer, Lucas; Walz, Katharine; Ramer-Tait, Amanda; Wannemuehler, Michael J; Narasimhan, Balaji

2013-01-01

Several challenges are associated with current vaccine strategies, including repeated immunizations, poor patient compliance, and limited approved routes for delivery, which may hinder induction of protective immunity. Thus, there is a need for new vaccine adjuvants capable of multi-route administration and prolonged antigen release at the site of administration by providing a depot within tissue. In this work, we designed a combinatorial platform to investigate the in vivo distribution, depot effect, and localized persistence of polyanhydride nanoparticles as a function of nanoparticle chemistry and administration route. Our observations indicated that the route of administration differentially affected tissue residence times. All nanoparticles rapidly dispersed when delivered intranasally but provided a depot when administered parenterally. When amphiphilic and hydrophobic nanoparticles were administered intranasally, they persisted within lung tissue. These results provide insights into the chemistry- and route-dependent distribution and tissue-specific association of polyanhydride nanoparticle-based vaccine adjuvants. PMID:23818778

Combinatorial evaluation of in vivo distribution of polyanhydride particle-based platforms for vaccine delivery.

PubMed

Petersen, Latrisha K; Huntimer, Lucas; Walz, Katharine; Ramer-Tait, Amanda; Wannemuehler, Michael J; Narasimhan, Balaji

2013-01-01

Several challenges are associated with current vaccine strategies, including repeated immunizations, poor patient compliance, and limited approved routes for delivery, which may hinder induction of protective immunity. Thus, there is a need for new vaccine adjuvants capable of multi-route administration and prolonged antigen release at the site of administration by providing a depot within tissue. In this work, we designed a combinatorial platform to investigate the in vivo distribution, depot effect, and localized persistence of polyanhydride nanoparticles as a function of nanoparticle chemistry and administration route. Our observations indicated that the route of administration differentially affected tissue residence times. All nanoparticles rapidly dispersed when delivered intranasally but provided a depot when administered parenterally. When amphiphilic and hydrophobic nanoparticles were administered intranasally, they persisted within lung tissue. These results provide insights into the chemistry- and route-dependent distribution and tissue-specific association of polyanhydride nanoparticle-based vaccine adjuvants.

Communication strategies to promote the uptake of childhood vaccination in Nigeria: a systematic map.

PubMed

Oku, Afiong; Oyo-Ita, Angela; Glenton, Claire; Fretheim, Atle; Ames, Heather; Muloliwa, Artur; Kaufman, Jessica; Hill, Sophie; Cliff, Julie; Cartier, Yuri; Bosch-Capblanch, Xavier; Rada, Gabriel; Lewin, Simon

2016-01-01

Effective communication is a critical component in ensuring that children are fully vaccinated. Although numerous communication interventions have been proposed and implemented in various parts of Nigeria, the range of communication strategies used has not yet been mapped systematically. This study forms part of the 'Communicate to vaccinate' (COMMVAC) project, an initiative aimed at building research evidence for improving communication with parents and communities about childhood vaccinations in low- and middle-income countries. This study aims to: 1) identify the communication strategies used in two states in Nigeria; 2) map these strategies against the existing COMMVAC taxonomy, a global taxonomy of vaccination communication interventions; 3) create a specific Nigerian country map of interventions organised by purpose and target; and 4) analyse gaps between the COMMVAC taxonomy and the Nigerian map. We conducted the study in two Nigerian states: Bauchi State in Northern Nigeria and Cross River State in Southern Nigeria. We identified vaccination communication interventions through interviews carried out among purposively selected stakeholders in the health services and relevant agencies involved in vaccination information delivery; through observations and through relevant documents. We used the COMMVAC taxonomy to organise the interventions we identified based on the intended purpose of the communication and the group to which the intervention was targeted. The Nigerian map revealed that most of the communication strategies identified aimed to inform and educate and remind or recall. Few aimed to teach skills, enhance community ownership, and enable communication. We did not identify any intervention that aimed to provide support or facilitate decision-making. Many interventions had more than one purpose. The main targets for most interventions were caregivers and community members, with few interventions directed at health workers. Most interventions

Recent advancement of gelatin nanoparticles in drug and vaccine delivery.

PubMed

Sahoo, Nityananda; Sahoo, Ranjan Ku; Biswas, Nikhil; Guha, Arijit; Kuotsu, Ketousetuo

2015-11-01

Novel drug delivery system using nanoscale materials with a broad spectrum of applications provides a new therapeutic foundation for technological integration and innovation. Nanoparticles are suitable drug carrier for various routes of administration as well as rapid recognition by the immune system. Gelatin, the biological macromolecule is a versatile drug/vaccine delivery carrier in pharmaceutical field due to its biodegradable, biocompatible, non-antigenicity and low cost with easy availability. The surface of gelatin nanoparticles can be modified with site-specific ligands, cationized with amine derivatives or, coated with polyethyl glycols to achieve targeted and sustained release drug delivery. Compared to other colloidal carriers, gelatin nanoparticles are better stable in biological fluids to provide the desired controlled and sustained release of entrapped drug molecules. The current review highlights the different formulation aspects of gelatin nanoparticles which affect the particle characteristics like zeta potential, polydispersity index, entrapment efficacy and drug release properties. It has also given emphasis on the major applications of gelatin nanoparticles in drug and vaccine delivery, gene delivery to target tissues and nutraceutical delivery for improving the poor bioavailabity of bioactive phytonutrients. Copyright © 2015 Elsevier B.V. All rights reserved.

Enhanced Delivery and Potency of Self-Amplifying mRNA Vaccines by Electroporation in Situ

PubMed Central

Cu, Yen; Broderick, Kate E.; Banerjee, Kaustuv; Hickman, Julie; Otten, Gillis; Barnett, Susan; Kichaev, Gleb; Sardesai, Niranjan Y.; Ulmer, Jeffrey B.; Geall, Andrew

2013-01-01

Nucleic acid-based vaccines such as viral vectors, plasmid DNA (pDNA), and mRNA are being developed as a means to address limitations of both live-attenuated and subunit vaccines. DNA vaccines have been shown to be potent in a wide variety of animal species and several products are now licensed for commercial veterinary but not human use. Electroporation delivery technologies have been shown to improve the generation of T and B cell responses from synthetic DNA vaccines in many animal species and now in humans. However, parallel RNA approaches have lagged due to potential issues of potency and production. Many of the obstacles to mRNA vaccine development have recently been addressed, resulting in a revival in the use of non-amplifying and self-amplifying mRNA for vaccine and gene therapy applications. In this paper, we explore the utility of EP for the in vivo delivery of large, self-amplifying mRNA, as measured by reporter gene expression and immunogenicity of genes encoding HIV envelope protein. These studies demonstrated that EP delivery of self-amplifying mRNA elicited strong and broad immune responses in mice, which were comparable to those induced by EP delivery of pDNA. PMID:26344119

Multifunctional particle-constituted microneedle arrays as cutaneous or mucosal vaccine adjuvant-delivery systems

PubMed Central

Wang, Xueting; Wang, Ning; Li, Ning; Zhen, Yuanyuan; Wang, Ting

2016-01-01

ABSTRACT To overcome drawbacks of current injection vaccines, such as causing needle phobia, needing health professionals for inoculation, and generating dangerous sharps wastes, researchers have designed novel vaccines that are combined with various microneedle arrays (MAs), in particular, with the multifunctional particle-constructed MAs (MPMAs). MPMAs prove able to enhance vaccine stability through incorporating vaccine ingredients in the carrier, and can be painlessly inoculated by minimally trained workers or by self-administration, leaving behind no metal needle pollution while eliciting robust systemic and mucosal immunity to antigens, thanks to delivering vaccines to cutaneous or mucosal compartments enriched in professional antigen-presenting cells (APCs). Especially, MPMAs can be easily integrated with functional molecules fulfilling targeting vaccine delivery or controlling immune response toward a Th1 or Th2 pathway to generate desired immunity against pathogens. Herein, we introduce the latest research and development of various MPMAs which are a novel but promising vaccine adjuvant delivery system (VADS). PMID:27159879

Co-delivery of PSA and PSMA DNA vaccines with electroporation induces potent immune responses.

PubMed

Ferraro, Bernadette; Cisper, Neil J; Talbott, Kendra T; Philipson-Weiner, Lindsey; Lucke, Colleen E; Khan, Amir S; Sardesai, Niranjan Y; Weiner, David B

2011-01-01

Prostate cancer (PCa) remains a significant public health problem. Current treatment modalities for PCa can be useful, but may be accompanied by deleterious side effects and often do not confer long-term control. Accordingly, additional modalities, such as immunotherapy, may represent an important approach for PCa treatment. The identification of tissue-specific antigens engenders PCa an attractive target for immunotherapeutic approaches. Delivery of DNA vaccines with electroporation has shown promising results for prophylactic and therapeutic targets in a variety of species including humans. Application of this technology for PCa immunotherapy strategies has been limited to single antigen and epitope targets. We sought to test the hypothesis that a broader collection of antigens would improve the breadth and effectiveness of a PCa immune therapy approach. We therefore developed highly optimized DNA vaccines encoding prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA) as a dual antigen approach to immune therapy of PCa. PSA-and PSMA-specific cellular immunogenicity was evaluated in a mouse model for co-delivery and single antigen vaccination. Mice received 2 immunizations spaced 2 weeks apart and immunogenicity was evaluated 1 week after the second vaccination. Both the PSA and PSMA vaccines induced robust antigen-specific IFNγ responses by ELISpot. Further characterization of cellular immunogenicity by flow cytometry indicated strong antigen-specific TNFα production by CD4+ T cells and IFNγ and IL-2 secretion by both CD4+ and CD8+ T cells. There was also a strong humoral response as determined by PSA-specific seroconversion. These data support further study of this novel approach to immune therapy of PCa.

Dengue vaccine development: strategies and challenges.

PubMed

Ramakrishnan, Lakshmy; Pillai, Madhavan Radhakrishna; Nair, Radhakrishnan R

2015-03-01

Infection with dengue virus may result in dengue fever or a more severe outcome, such as dengue hemorrhagic syndrome/shock. Dengue virus infection poses a threat to endemic regions for four reasons: the presence of four serotypes, each with the ability to cause a similar disease outcome, including fatality; difficulties related to vector control; the lack of specific treatment; and the nonavailability of a suitable vaccine. Vaccine development is considered challenging due to the severity of the disease observed in individuals who have acquired dengue-specific immunity, either passively or actively. Therefore, the presence of vaccine-induced immunity against a particular serotype may prime an individual to severe disease on exposure to dengue virus. Vaccine development strategies include live attenuated vaccines, chimeric, DNA-based, subunit, and inactivated vaccines. Each of the candidates is in various stages of preclinical and clinical development. Issues pertaining to selection pressures, viral interaction, and safety still need to be evaluated in order to induce a complete protective immune response against all four serotypes. This review highlights the various strategies that have been employed in vaccine development, and identifies the obstacles to producing a safe and effective vaccine.

Understanding HIV infection for the design of a therapeutic vaccine. Part II: Vaccination strategies for HIV.

PubMed

de Goede, A L; Vulto, A G; Osterhaus, A D M E; Gruters, R A

2015-05-01

HIV infection leads to a gradual loss CD4(+) T lymphocytes comprising immune competence and progression to AIDS. Effective treatment with combined antiretroviral drugs (cART) decreases viral load below detectable levels but is not able to eliminate the virus from the body. The success of cART is frustrated by the requirement of expensive lifelong adherence, accumulating drug toxicities and chronic immune activation resulting in increased risk of several non-AIDS disorders, even when viral replication is suppressed. Therefore, there is a strong need for therapeutic strategies as an alternative to cART. Immunotherapy, or therapeutic vaccination, aims to increase existing immune responses against HIV or induce de novo immune responses. These immune responses should provide a functional cure by controlling viral replication and preventing disease progression in the absence of cART. The key difficulty in the development of an HIV vaccine is our ignorance of the immune responses that control of viral replication, and thus how these responses can be elicited and how they can be monitored. Part one of this review provides an extensive overview of the (patho-) physiology of HIV infection. It describes the structure and replication cycle of HIV, the epidemiology and pathogenesis of HIV infection and the innate and adaptive immune responses against HIV. Part two of this review discusses therapeutic options for HIV. Prevention modalities and antiretroviral therapy are briefly touched upon, after which an extensive overview on vaccination strategies for HIV is provided, including the choice of immunogens and delivery strategies. Copyright © 2014. Published by Elsevier Masson SAS.

Evaluating a strategy to deliver vaccine to white-tailed deer at a landscape level

USGS Publications Warehouse

Fischer, Justin W.; Blass, Chad R.; Walter, W. David; Anderson, Charles W.; Lavelle, Michael J.; Hall, Wayne H.; VerCauterren, Kurt C.

2016-01-01

Effective delivery of vaccines and other pharmaceuticals to wildlife populations is needed when zoonotic diseases pose a risk to public health and natural resources or have considerable economic consequences. The objective of our study was to develop a bait-distribution strategy for potential delivery of oral bovine tuberculosis (bTB) vaccine to white-tailed deer (Odocoileus virginianus) where deer are reservoirs for the disease. During 17 February and 2 March 2011, we created a grid of experimental bait stations (n = 64) on Sandhill Wildlife Management Area, Wisconsin, USA, to assess station densities needed to attract and deliver placebo baits to free-ranging white-tailed deer and look for associations among deer density, number of bait stations per deer, and bait consumption. We placed 1 L of commercially available alfalfa cubes at bait stations 652 m apart, and monitored stations with motion-activated cameras for 5 days to document visitation and consumption by deer and nontarget species. Deer discovered 38% of all bait stations within 37 hr, on average (SE = 3.91 hr), and consumed variable amounts of bait at each station. Deer were documented in 94% of all photographs of wildlife at bait stations. We found no correlation between bait consumption and deer density or the number of bait stations per deer. We provide the first information on use of baits by free-ranging deer and nontarget wildlife to eventually vaccinate deer against bTB at a landscape level. The results of this study can further the development of strategies in delivery of pharmaceuticals to free-ranging white-tailed deer.

Transdermal drug delivery

PubMed Central

Prausnitz, Mark R.; Langer, Robert

2009-01-01

Transdermal drug delivery has made an important contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, non-cavitational ultrasound and iontophoresis have also resulted in clinical products; the ability of iontophoresis to control delivery rates in real time provides added functionality. Third-generation delivery systems target their effects to skin’s barrier layer of stratum corneum using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound. Microneedles and thermal ablation are currently progressing through clinical trials for delivery of macromolecules and vaccines, such as insulin, parathyroid hormone and influenza vaccine. Using these novel second- and third-generation enhancement strategies, transdermal delivery is poised to significantly increase impact on medicine. PMID:18997767

Home delivery of heat-stable vaccines in Indonesia: outreach immunization with a prefilled, single-use injection device.

PubMed Central

Sutanto, A.; Suarnawa, I. M.; Nelson, C. M.; Stewart, T.; Soewarso, T. I.

1999-01-01

Extending immunization coverage to underserved populations will require innovative immunization strategies. This study evaluated one such strategy: the use of a prefilled, single-use injection device for outreach immunization by village midwives. The device, UniJect, is designed to prevent refilling or reuse. Stored at ambient temperatures for up to 1 month in midwives' homes, vaccine-filled UniJect devices were immediately available for outreach. Between July 1995 and April 1996, 110 midwives on the Indonesia islands of Lombok and Bali visited the homes of newborn infants to deliver hepatitis B vaccine to the infants and tetanus toxoid to their mothers. Observations and interviews showed that the midwives used the device properly and safely to administer approximately 10,000 sterile injections in home settings. There were no problems with excessive heat exposure during the storage or delivery of vaccine. Injection recipients and midwives expressed a strong preference for the UniJect device over a standard syringe. Use of the prefilled device outside the cold chain simplified the logistics and facilitated the speed and efficiency of home visits, while the single-dose format minimized vaccine wastage. PMID:10083709

Evaluation of human papilloma virus (HPV) vaccination strategies and vaccination coverage in adolescent girls worldwide.

PubMed

Owsianka, Barbara; Gańczak, Maria

2015-01-01

An analysis of HPV vaccination strategies and vaccination coverage in adolescent girls worldwide for the last eight years with regard to potential improvement of vaccination coverage rates in Poland. Literature search, covering the period 2006-2014, was performed using Medline. Comparative analysis of HPV vaccination strategies and coverage between Poland and other countries worldwide was conducted. In the last eight years, a number of countries introduced HPV vaccination for adolescent girls to their national immunization programmes. Vaccination strategies differ, consequently affecting vaccination coverage, ranging from several percent to more than 90%. Usually, there are also disparities at national level. The highest HPV vaccination coverage rates are observed in countries where vaccines are administered in school settings and funded from the national budget. Poland is one of the eight EU countries where HPV vaccination has not been introduced to mandatory immunization programme and where paid vaccination is only provided in primary health care settings. HPV vaccination coverage in adolescent girls is estimated at 7.5-10%. Disparities in HPV vaccination coverage rates in adolescent girls worldwide may be due to different strategies of vaccination implementation between countries. Having compared to other countries, the low HPV vaccination coverage in Polish adolescent girls may result from the lack of funding at national level and the fact that vaccines are administered in a primary health care setting. A multidimensional approach, involving the engagement of primary health care and school personnel as well as financial assistance of government at national and local level and the implementation of media campaigns, particularly in regions with high incidence of cervical cancer, could result in an increase of HPV vaccination coverage rates in Poland.

Transport networks and inequities in vaccination: remoteness shapes measles vaccine coverage and prospects for elimination across Africa.

PubMed

Metcalf, C J E; Tatem, A; Bjornstad, O N; Lessler, J; O'Reilly, K; Takahashi, S; Cutts, F; Grenfell, B T

2015-05-01

Measles vaccination is estimated to have averted 13·8 million deaths between 2000 and 2012. Persisting heterogeneity in coverage is a major contributor to continued measles mortality, and a barrier to measles elimination and introduction of rubella-containing vaccine. Our objective is to identify determinants of inequities in coverage, and how vaccine delivery must change to achieve elimination goals, which is a focus of the WHO Decade of Vaccines. We combined estimates of travel time to the nearest urban centre (⩾50 000 people) with vaccination data from Demographic Health Surveys to assess how remoteness affects coverage in 26 African countries. Building on a statistical mapping of coverage against age and geographical isolation, we quantified how modifying the rate and age range of vaccine delivery affects national coverage. Our scenario analysis considers increasing the rate of delivery of routine vaccination, increasing the target age range of routine vaccination, and enhanced delivery to remote areas. Geographical isolation plays a key role in defining vaccine inequity, with greater inequity in countries with lower measles vaccine coverage. Eliminating geographical inequities alone will not achieve thresholds for herd immunity, indicating that changes in delivery rate or age range of routine vaccination will be required. Measles vaccine coverage remains far below targets for herd immunity in many countries on the African continent and is likely to be inadequate for achieving rubella elimination. The impact of strategies such as increasing the upper age range eligible for routine vaccination should be considered.

[Vaccine application of recombinant herpesviruses].

PubMed

Yokoyama, N; Xuan, X; Mikami, T

2000-04-01

Recently, genetic engineering using recombinant DNA techniques has been applied to design new viral vaccines in order to reduce some problems which the present viral vaccines have. Up to now, many viruses have been investigated for development of recombinant attenuated vaccines or live viral vectors for delivery of foreign genes coding immunogenic antigens. In this article, we introduced the new vaccine strategy using genetically engineered herpesviruses.

Transfollicular delivery takes root: the future for vaccine design?

PubMed

Hansen, Steffi; Lehr, Claus-Michael

2014-01-01

The immunological environment of hair follicles has lately received the attention of researchers in the context of transfollicular drug delivery, particularly for improving needle-free transcutaneous immunization. Hair follicles represent shunt pathways across the stratum corneum barrier, which may facilitate the absorption of large or hydrophilic molecules such as vaccine antigens. Currently researchers have identified opportunities and challenges created by transfollicular vaccination. Nanotechnology may facilitate transfollicular delivery in several ways as nanoparticles penetrate deeper and to a higher extent into hair follicles than solutions. Also, nanoencapsulation can stabilize antigens and increase their antigenicity. This seems necessary as only a limited portion of topically applied antigen is available via the hair follicles and as the responsiveness of perifollicular Langerhans cells varies during hair cycle. These problems may be overcome by developing more efficient adjuvant-coupled nanocarriers with high antigen payload.

Vaccination strategies for SIR vector-transmitted diseases.

PubMed

Cruz-Pacheco, Gustavo; Esteva, Lourdes; Vargas, Cristobal

2014-08-01

Vector-borne diseases are one of the major public health problems in the world with the fastest spreading rate. Control measures have been focused on vector control, with poor results in most cases. Vaccines should help to reduce the diseases incidence, but vaccination strategies should also be defined. In this work, we propose a vector-transmitted SIR disease model with age-structured population subject to a vaccination program. We find an expression for the age-dependent basic reproductive number R(0), and we show that the disease-free equilibrium is locally stable for R(0) ≤ 1, and a unique endemic equilibrium exists for R(0) > 1. We apply the theoretical results to public data to evaluate vaccination strategies, immunization levels, and optimal age of vaccination for dengue disease.

Vial usage, device dead space, vaccine wastage, and dose accuracy of intradermal delivery devices for inactivated poliovirus vaccine (IPV).

PubMed

Jarrahian, Courtney; Rein-Weston, Annie; Saxon, Gene; Creelman, Ben; Kachmarik, Greg; Anand, Abhijeet; Zehrung, Darin

2017-03-27

Intradermal delivery of a fractional dose of inactivated poliovirus vaccine (IPV) offers potential benefits compared to intramuscular (IM) delivery, including possible cost reductions and easing of IPV supply shortages. Objectives of this study were to assess intradermal delivery devices for dead space, wastage generated by the filling process, dose accuracy, and total number of doses that can be delivered per vial. Devices tested included syringes with staked (fixed) needles (autodisable syringes and syringes used with intradermal adapters), a luer-slip needle and syringe, a mini-needle syringe, a hollow microneedle device, and disposable-syringe jet injectors with their associated filling adapters. Each device was used to withdraw 0.1-mL fractional doses from single-dose IM glass vials which were then ejected into a beaker. Both vial and device were weighed before and after filling and again after expulsion of liquid to record change in volume at each stage of the process. Data were used to calculate the number of doses that could potentially be obtained from multidose vials. Results show wide variability in dead space, dose accuracy, overall wastage, and total number of doses that can be obtained per vial among intradermal delivery devices. Syringes with staked needles had relatively low dead space and low overall wastage, and could achieve a greater number of doses per vial compared to syringes with a detachable luer-slip needle. Of the disposable-syringe jet injectors tested, one was comparable to syringes with staked needles. If intradermal delivery of IPV is introduced, selection of an intradermal delivery device can have a substantial impact on vaccine wasted during administration, and thus on the required quantity of vaccine that needs to be purchased. An ideal intradermal delivery device should be not only safe, reliable, accurate, and acceptable to users and vaccine recipients, but should also have low dead space, high dose accuracy, and low overall

Optimal H1N1 vaccination strategies based on self-interest versus group interest.

PubMed

Shim, Eunha; Meyers, Lauren Ancel; Galvani, Alison P

2011-02-25

Influenza vaccination is vital for reducing H1N1 infection-mediated morbidity and mortality. To reduce transmission and achieve herd immunity during the initial 2009-2010 pandemic season, the US Centers for Disease Control and Prevention (CDC) recommended that initial priority for H1N1 vaccines be given to individuals under age 25, as these individuals are more likely to spread influenza than older adults. However, due to significant delay in vaccine delivery for the H1N1 influenza pandemic, a large fraction of population was exposed to the H1N1 virus and thereby obtained immunity prior to the wide availability of vaccines. This exposure affects the spread of the disease and needs to be considered when prioritizing vaccine distribution. To determine optimal H1N1 vaccine distributions based on individual self-interest versus population interest, we constructed a game theoretical age-structured model of influenza transmission and considered the impact of delayed vaccination. Our results indicate that if individuals decide to vaccinate according to self-interest, the resulting optimal vaccination strategy would prioritize adults of age 25 to 49 followed by either preschool-age children before the pandemic peak or older adults (age 50-64) at the pandemic peak. In contrast, the vaccine allocation strategy that is optimal for the population as a whole would prioritize individuals of ages 5 to 64 to curb a growing pandemic regardless of the timing of the vaccination program. Our results indicate that for a delayed vaccine distribution, the priorities that are optimal at a population level do not align with those that are optimal according to individual self-interest. Moreover, the discordance between the optimal vaccine distributions based on individual self-interest and those based on population interest is even more pronounced when vaccine availability is delayed. To determine optimal vaccine allocation for pandemic influenza, public health agencies need to consider

Communication strategies to promote the uptake of childhood vaccination in Nigeria: a systematic map

PubMed Central

Oku, Afiong; Oyo-Ita, Angela; Glenton, Claire; Fretheim, Atle; Ames, Heather; Muloliwa, Artur; Kaufman, Jessica; Hill, Sophie; Cliff, Julie; Cartier, Yuri; Bosch-Capblanch, Xavier; Rada, Gabriel; Lewin, Simon

2016-01-01

Background Effective communication is a critical component in ensuring that children are fully vaccinated. Although numerous communication interventions have been proposed and implemented in various parts of Nigeria, the range of communication strategies used has not yet been mapped systematically. This study forms part of the ‘Communicate to vaccinate’ (COMMVAC) project, an initiative aimed at building research evidence for improving communication with parents and communities about childhood vaccinations in low- and middle-income countries. Objective This study aims to: 1) identify the communication strategies used in two states in Nigeria; 2) map these strategies against the existing COMMVAC taxonomy, a global taxonomy of vaccination communication interventions; 3) create a specific Nigerian country map of interventions organised by purpose and target; and 4) analyse gaps between the COMMVAC taxonomy and the Nigerian map. Design We conducted the study in two Nigerian states: Bauchi State in Northern Nigeria and Cross River State in Southern Nigeria. We identified vaccination communication interventions through interviews carried out among purposively selected stakeholders in the health services and relevant agencies involved in vaccination information delivery; through observations and through relevant documents. We used the COMMVAC taxonomy to organise the interventions we identified based on the intended purpose of the communication and the group to which the intervention was targeted. Results The Nigerian map revealed that most of the communication strategies identified aimed to inform and educate and remind or recall. Few aimed to teach skills, enhance community ownership, and enable communication. We did not identify any intervention that aimed to provide support or facilitate decision-making. Many interventions had more than one purpose. The main targets for most interventions were caregivers and community members, with few interventions directed at

Economic analysis of pandemic influenza vaccination strategies in Singapore.

PubMed

Lee, Vernon J; Tok, Mei Yin; Chow, Vincent T; Phua, Kai Hong; Ooi, Eng Eong; Tambyah, Paul A; Chen, Mark I

2009-09-22

All influenza pandemic plans advocate pandemic vaccination. However, few studies have evaluated the cost-effectiveness of different vaccination strategies. This paper compares the economic outcomes of vaccination compared with treatment with antiviral agents alone, in Singapore. We analyzed the economic outcomes of pandemic vaccination (immediate vaccination and vaccine stockpiling) compared with treatment-only in Singapore using a decision-based model to perform cost-benefit and cost-effectiveness analyses. We also explored the annual insurance premium (willingness to pay) depending on the perceived risk of the next pandemic occurring. The treatment-only strategy resulted in 690 deaths, 13,950 hospitalization days, and economic cost of USD$497 million. For immediate vaccination, at vaccine effectiveness of >55%, vaccination was cost-beneficial over treatment-only. Vaccine stockpiling is not cost-effective in most scenarios even with 100% vaccine effectiveness. The annual insurance premium was highest with immediate vaccination, and was lower with increased duration to the next pandemic. The premium was also higher with higher vaccine effectiveness, attack rates, and case-fatality rates. Stockpiling with case-fatality rates of 0.4-0.6% would be cost-beneficial if vaccine effectiveness was >80%; while at case-fatality of >5% stockpiling would be cost-beneficial even if vaccine effectiveness was 20%. High-risk sub-groups warrant higher premiums than low-risk sub-groups. The actual pandemic vaccine effectiveness and lead time is unknown. Vaccine strategy should be based on perception of severity. Immediate vaccination is most cost-effective, but requires vaccines to be available when required. Vaccine stockpiling as insurance against worst-case scenarios is also cost-effective. Research and development is therefore critical to develop and stockpile cheap, readily available effective vaccines.

Turning self-destructing Salmonella into a universal DNA vaccine delivery platform.

PubMed

Kong, Wei; Brovold, Matthew; Koeneman, Brian A; Clark-Curtiss, Josephine; Curtiss, Roy

2012-11-20

We previously developed a biological containment system using recombinant Salmonella Typhimurium strains that are attenuated yet capable of synthesizing protective antigens. The regulated delayed attenuation and programmed self-destructing features designed into these S. Typhimurium strains enable them to efficiently colonize host tissues and allow release of the bacterial cell contents after lysis. To turn such a recombinant attenuated Salmonella vaccine (RASV) strain into a universal DNA vaccine-delivery vehicle, our approach was to genetically modify RASV strains to display a hyperinvasive phenotype to maximize Salmonella host entry and host cell internalization, to enable Salmonella endosomal escape to release a DNA vaccine into the cytosol, and to decrease Salmonella-induced pyroptosis/apoptosis that allows the DNA vaccine time to traffic to the nucleus for efficient synthesis of encoded protective antigens. A DNA vaccine vector that encodes a domain that contributes to the arabinose-regulated lysis phenotype but has a eukaryotic promoter was constructed. The vector was then improved by insertion of multiple DNA nuclear-targeting sequences for efficient nuclear trafficking and gene expression, and by increasing nuclease resistance to protect the plasmid from host degradation. A DNA vaccine encoding influenza WSN virus HA antigen delivered by the RASV strain with the best genetic attributes induced complete protection to mice against a lethal influenza virus challenge. Adoption of these technological improvements will revolutionize means for effective delivery of DNA vaccines to stimulate mucosal, systemic, and cellular protective immunities, and lead to a paradigm shift in cost-effective control and prevention of a diversity of diseases.

Turning self-destructing Salmonella into a universal DNA vaccine delivery platform

PubMed Central

Kong, Wei; Brovold, Matthew; Koeneman, Brian A.; Clark-Curtiss, Josephine; Curtiss, Roy

2012-01-01

We previously developed a biological containment system using recombinant Salmonella Typhimurium strains that are attenuated yet capable of synthesizing protective antigens. The regulated delayed attenuation and programmed self-destructing features designed into these S. Typhimurium strains enable them to efficiently colonize host tissues and allow release of the bacterial cell contents after lysis. To turn such a recombinant attenuated Salmonella vaccine (RASV) strain into a universal DNA vaccine-delivery vehicle, our approach was to genetically modify RASV strains to display a hyperinvasive phenotype to maximize Salmonella host entry and host cell internalization, to enable Salmonella endosomal escape to release a DNA vaccine into the cytosol, and to decrease Salmonella-induced pyroptosis/apoptosis that allows the DNA vaccine time to traffic to the nucleus for efficient synthesis of encoded protective antigens. A DNA vaccine vector that encodes a domain that contributes to the arabinose-regulated lysis phenotype but has a eukaryotic promoter was constructed. The vector was then improved by insertion of multiple DNA nuclear-targeting sequences for efficient nuclear trafficking and gene expression, and by increasing nuclease resistance to protect the plasmid from host degradation. A DNA vaccine encoding influenza WSN virus HA antigen delivered by the RASV strain with the best genetic attributes induced complete protection to mice against a lethal influenza virus challenge. Adoption of these technological improvements will revolutionize means for effective delivery of DNA vaccines to stimulate mucosal, systemic, and cellular protective immunities, and lead to a paradigm shift in cost-effective control and prevention of a diversity of diseases. PMID:23129620

Technical Transformation of Biodefense Vaccines

PubMed Central

Lu, Shan; Wang, Shixia

2013-01-01

Biodefense vaccines are developed against a diverse group of pathogens. Vaccines were developed for some of these pathogens a long time ago but they are facing new challenges to move beyond the old manufacturing technologies. New vaccines to be developed against other pathogens have to determine whether to follow traditional vaccination strategies or to seek new approaches. Advances in basic immunology and recombinant DNA technology have fundamentally transformed the process of formulating a vaccine concept, optimizing protective antigens, and selecting the most effective vaccine delivery approach for candidate biodefense vaccines. PMID:19837293

Trends affecting the future of vaccine development and delivery: The role of demographics, regulatory science, the anti-vaccine movement, and vaccinomics

PubMed Central

Poland, Gregory A.; Jacobson, Robert M.; Ovsyannikova, Inna G.

2009-01-01

Important scientific, cultural, temporal, and secular issues impact the development of, and delivery of vaccines. In this paper we discuss the impact of demographics, regulatory science, the anti-vaccine movement, and finally the impact of the new biology and individualized medicine, which we call vaccinomics, on vaccine development and delivery. A description of the issues and how they have, are, or should be impacting vaccinology is provided, and hopefully will result in increased attention and discussion among vaccinologists. These issues have been under-valued, under-discussed, and in some cases, ignored. We hope that discussion of these issues will result in changes in how we develop, and how we communicate those developments, to the public. PMID:19200833

Vaccine delivery to disease control: a paradigm shift in health policy.

PubMed

John, T Jacob; Jain, Yogesh; Nadimpally, Sarojini; Jesani, Amar

2017-01-01

India's Universal Immunisation Programme (UIP) has resulted in the creation of infrastructure, human resources and systems for the procurement and delivery of vaccines. Recently, new vaccines have been added and there are plans for the introduction of more. However, the outcomes in terms of reduction of the diseases for which the vaccines are being administered remain ambiguous. This is evident from the persistent health issues that children continue to experience, despite immunisation. This situation raises a fundamental ethical question for public health: vaccinations are one of the tools of disease control, but are they properly aligned to the control of disease so as to produce the expected public health utility or benefit?

[Economic evaluation on different two-dose-vaccination-strategies related to Measles, Mumps and Rubella Combined Attenuated Live Vaccine].

PubMed

He, H Q; Zhang, B; Yan, R; Li, Q; Fu, J; Tang, X W; Zhou, Y; Deng, X; Xie, S Y

2016-08-10

To evaluate the economic effect of Measles, Mumps and Rubella Combined Attenuated Live Vaccine (MMR) under different two-dose vaccination programs. A hypothetical birth cohort of 750 000 infants over their lifetime, was followed up from birth through death in Zhejiang province. The current MMR vaccination strategie would include three different ones: 1) Childlern were vaccinated with Measles-Rubella Combined Attenuated Live Vaccine and MMR, respectively at the age of 8 months and 18 months. 2) Children receive MMR at 8 months and 18 months, 3) Strategy 1 plus an additional vaccination of MMR at 4 years of age. Incremental cost-effectiveness ratio (ICER), incremental cost-benefit ratio (ICBR) and incremental net benefit (INB) were applied to calculate the health economic difference for Strategy 2 and Strategy 3 as compared to Strategy 1. Univariate sensitivity analysis was used to assess the robustness of results with main parameters, including the rate of immunization coverage, effectiveness of the vaccines, incidence and burdens of the related diseases, cost of vaccines and the vaccination program itself. ICER, ICBR and INB for Strategy 2 and Strategy 3 appeared as 2 012.51∶1 RMB Yuan per case and 4 238.72∶1 RMB Yuan per case, 1∶3.14 and 1∶1.58, 21 277 800 RMB Yuan and 9 276 500 RMB Yuan, respectively. Only slight changes (<20%) were found under the univariate sensitivity analysis, with varied values on main parameters. Based on the current national immunization program, infants vaccinated with MMR at 8 months of age, generated more health economic effects than the Strategy 3.

Increase in DNA vaccine efficacy by virosome delivery and co-expression of a cytolytic protein.

PubMed

Gargett, Tessa; Grubor-Bauk, Branka; Miller, Darren; Garrod, Tamsin; Yu, Stanley; Wesselingh, Steve; Suhrbier, Andreas; Gowans, Eric J

2014-06-01

The potential of DNA vaccines has not been realised due to suboptimal delivery, poor antigen expression and the lack of localised inflammation, essential for antigen presentation and an effective immune response to the immunogen. Initially, we examined the delivery of a DNA vaccine encoding a model antigen, luciferase (LUC), to the respiratory tract of mice by encapsulation in a virosome. Virosomes that incorporated influenza virus haemagglutinin effectively delivered DNA to cells in the mouse respiratory tract and resulted in antigen expression and systemic and mucosal immune responses to the immunogen after an intranasal (IN) prime/intradermal (ID) boost regimen, whereas a multidose ID regimen only generated systemic immunity. We also examined systemic immune responses to LUC after ID vaccination with a DNA vaccine, which also encoded one of the several cytolytic or toxic proteins. Although the herpes simplex virus thymidine kinase, in the presence of the prodrug, ganciclovir, resulted in cell death, this failed to increase the humoral or cell-mediated immune responses. In contrast, the co-expression of LUC with the rotavirus non-structural protein 4 (NSP4) protein or a mutant form of mouse perforin, proteins which are directly cytolytic, resulted in increased LUC-specific humoral and cell-mediated immunity. On the other hand, co-expression of LUC with diphtheria toxin subunit A or overexpression of perforin or NSP4 resulted in a lower level of immunity. In summary, the efficacy of DNA vaccines can be improved by targeted IN delivery of DNA or by the induction of cell death in vaccine-targeted cells after ID delivery.

Virus-Like Particle, Liposome, and Polymeric Particle-Based Vaccines against HIV-1

PubMed Central

Gao, Yong; Wijewardhana, Chanuka; Mann, Jamie F. S.

2018-01-01

It is acknowledged that vaccines remain the best hope for eliminating the HIV-1 epidemic. However, the failure to produce effective vaccine immunogens and the inability of conventional delivery strategies to elicit the desired immune responses remains a central theme and has ultimately led to a significant roadblock in HIV vaccine development. Consequently, significant efforts have been applied to generate novel vaccine antigens and delivery agents, which mimic viral structures for optimal immune induction. Here, we review the latest developments that have occurred in the nanoparticle vaccine field, with special emphasis on strategies that are being utilized to attain highly immunogenic, systemic, and mucosal anti-HIV humoral and cellular immune responses. This includes the design of novel immunogens, the central role of antigen-presenting cells, delivery routes, and biodistribution of nanoparticles to lymph nodes. In particular, we will focus on virus-like-particle formulations and their preclinical uses within the HIV prophylactic vaccine setting. PMID:29541072

Nanogel antigenic protein-delivery system for adjuvant-free intranasal vaccines

NASA Astrophysics Data System (ADS)

Nochi, Tomonori; Yuki, Yoshikazu; Takahashi, Haruko; Sawada, Shin-Ichi; Mejima, Mio; Kohda, Tomoko; Harada, Norihiro; Kong, Il Gyu; Sato, Ayuko; Kataoka, Nobuhiro; Tokuhara, Daisuke; Kurokawa, Shiho; Takahashi, Yuko; Tsukada, Hideo; Kozaki, Shunji; Akiyoshi, Kazunari; Kiyono, Hiroshi

2010-07-01

Nanotechnology is an innovative method of freely controlling nanometre-sized materials. Recent outbreaks of mucosal infectious diseases have increased the demands for development of mucosal vaccines because they induce both systemic and mucosal antigen-specific immune responses. Here we developed an intranasal vaccine-delivery system with a nanometre-sized hydrogel (`nanogel') consisting of a cationic type of cholesteryl-group-bearing pullulan (cCHP). A non-toxic subunit fragment of Clostridium botulinum type-A neurotoxin BoHc/A administered intranasally with cCHP nanogel (cCHP-BoHc/A) continuously adhered to the nasal epithelium and was effectively taken up by mucosal dendritic cells after its release from the cCHP nanogel. Vigorous botulinum-neurotoxin-A-neutralizing serum IgG and secretory IgA antibody responses were induced without co-administration of mucosal adjuvant. Importantly, intranasally administered cCHP-BoHc/A did not accumulate in the olfactory bulbs or brain. Moreover, intranasally immunized tetanus toxoid with cCHP nanogel induced strong tetanus-toxoid-specific systemic and mucosal immune responses. These results indicate that cCHP nanogel can be used as a universal protein-based antigen-delivery vehicle for adjuvant-free intranasal vaccination.

[Pertussis in fully vaccinated infants and children. Are new vaccination strategies required?].

PubMed

Moraga-Llop, Fernando A; Mendoza-Palomar, Natàlia; Muntaner-Alonso, Antoni; Codina-Grau, Gemma; Fàbregas-Martori, Anna; Campins-Martí, Magda

2014-04-01

To analyse the vaccination status of children diagnosed with pertussis and to compare the clinical manifestations of fully vaccinated with unvaccinated, or incompletely-vaccinated, children. The clinical histories and vaccination cards of patients under 16years of age seen in the Emergency Room of the University Hospital Vall d'Hebron, Barcelona (Spain), for pertussis confirmed by a microbiological study were reviewed. The study period lasted from January 1, 2009 to December 31, 2011. Two hundred and twelve cases were studied: 35 in 2009, 28 in 2010 and 149 in 2011. RT-PCR was positive in 210 patients, and 73 had a positive culture. Infants under 6months of age account for 36.8% of all cases. Forty-four patients (21.5%) were not vaccinated. Forty-four (21.5%) children were between 2 and 5months of age and had received 1-2vaccine doses. One hundred and seventeen (57%) children were fully vaccinated; 76.9% (90cases) had received the last dose less than 4years ago. When clinical manifestations of the fully vaccinated patients were compared with those of the non-vaccinated or incompletely-vaccinated children, only cyanosis was found with a higher frequency in the latter group (P<.001). The age-adjusted probability of hospitalisation was significantly associated with non-vaccination (P=.001). The case mortality rate among inpatients was 1.3%. The number of pertussis cases seen in our centre has risen significantly in the last year. More than half (57%) of the patients were fully vaccinated, and 76.9% had received the last dose in the previous 4years. Other vaccination strategies, such as vaccination of adolescents, adults, and pregnant women, as well as a cocoon strategy are required to protect infants under 6months of age. More effective vaccines need to be developed. Copyright © 2012 Elsevier España, S.L. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Development of Tat-Conjugated Dendrimer for Transdermal DNA Vaccine Delivery.

PubMed

Bahadoran, Azadeh; Moeini, Hassan; Bejo, Mohd Hair; Hussein, Mohd Zobir; Omar, Abdul Rahman

In order to enhance cellular uptake and to facilitate transdermal delivery of DNA vaccine, polyamidoamine (PAMAM) dendrimers conjugated with HIV transactivator of transcription (TAT) was developed. First, the plasmid DNA (pIRES-H5/GFP) nanoparticle was formulated using PAMAM dendrimer and TAT peptide and then characterized for surface charge, particle size, DNA encapsulation and protection of the pIRES-H5/GFP DNA plasmid to enzymatic digestion. Subsequently, the potency of the TAT-conjugated dendrimer for gene delivery was evaluated through in vitro transfection into Vero cells followed by gene expression analysis including western blotting, fluorescent microscopy and PCR. The effect of the TAT peptide on cellular uptake of DNA vaccine was studied by qRT-PCR and flow cytometry. Finally, the ability of TAT-conjugated PAMAM dendrimer for transdermal delivery of the DNA plasmid was assessed through artificial membranes followed by qRT-PCR and flow cytometry. TAT-conjugated PAMAM dendrimer showed the ability to form a compact and nanometre-sized polyplexes with the plasmid DNA, having the size range of 105 to 115 nm and a positive charge of +42 to +45 mV over the N/P ratio of 6:1(+/-).  In vitro transfection analysis into Vero cells confirms the high potency of TAT-conjugated PAMAM dendrimer to enhance the cellular uptake of DNA vaccine.  The permeability value assay through artificial membranes reveals that TAT-conjugated PAMAM has more capacity for transdermal delivery of the DNA compared to unmodified PAMAM dendrimer (P<0.05). The findings of this study suggest that TAT-conjugated PAMAM dendrimer is a promising non-viral vector for transdermal use.This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Protective immunity in mice achieved with dry powder formulation and alternative delivery of plague F1-V vaccine.

PubMed

Huang, Joanne; D'Souza, Ajit J; Alarcon, Jason B; Mikszta, John A; Ford, Brandi M; Ferriter, Matthew S; Evans, Michelle; Stewart, Todd; Amemiya, Kei; Ulrich, Robert G; Sullivan, Vincent J

2009-05-01

The potential use of Yersinia pestis as a bioterror agent is a great concern. Development of a stable powder vaccine against Y. pestis and administration of the vaccine by minimally invasive methods could provide an alternative to the traditional liquid formulation and intramuscular injection. We evaluated a spray-freeze-dried powder vaccine containing a recombinant F1-V fusion protein of Y. pestis for vaccination against plaque in a mouse model. Mice were immunized with reconstituted spray-freeze-dried F1-V powder via intramuscular injection, microneedle-based intradermal delivery, or noninvasive intranasal administration. By intramuscular injection, the reconstituted powder induced serum antibody responses and provided protection against lethal subcutaneous challenge with 1,000 50% lethal doses of Y. pestis at levels equivalent to those elicited by unprocessed liquid formulations (70 to 90% protection). The feasibility of intradermal and intranasal delivery of reconstituted powder F1-V vaccine was also demonstrated. Overall, microneedle-based intradermal delivery was shown to be similar in efficacy to intramuscular injection, while intranasal administration required an extra dose of vaccine to achieve similar protection. In addition, the results suggest that seroconversion against F1 may be a better predictor of protection against Y. pestis challenge than seroconversion against either F1-V or V. In summary, we demonstrate the preclinical feasibility of using a reconstituted powder F1-V formulation and microneedle-based intradermal delivery to provide protective immunity against plague in a mouse model. Intranasal delivery, while feasible, was less effective than injection in this study. The potential use of these alternative delivery methods and a powder vaccine formulation may result in substantial health and economic benefits.

Monodisperse, Uniformly-Shaped Particles for Controlled Respiratory Vaccine Delivery

NASA Astrophysics Data System (ADS)

Fromen, Catherine Ann

The majority of the world's most infectious diseases occur at the air-tissue interface called the mucosa, including HIV/AIDS, tuberculosis, measles, and bacterial or viral gut and respiratory infections. Despite this, vaccines have generally been developed for the systemic immune system and fail to provide protection at the mucosal site. Vaccine delivery directly to the lung mucosa could provide superior lung protection for many infectious diseases, such as TB or influenza, as well as systemic and therapeutic vaccines for diseases such as Dengue fever, asthma, or cancer. Specifically, precision engineered biomaterials are believed to offer tremendous opportunities for a new generation of vaccines. The goal of this approach is to leverage naturally occurring processes of the immune system to produce memory responses capable of rapidly destroy virulent pathogens without harmful exposure. Considerable knowledge of biomaterial properties and their interaction with the immune system of the lung is required for successful translation. The overall goal of this work was to fabricate and characterize nano- and microparticles using the Particle Replication In Non-wetting Templates (PRINT) fabrication technique and optimize them as pulmonary vaccine carriers. (Abstract shortened by ProQuest.).

Nanovaccines : nanocarriers for antigen delivery.

PubMed

Gonzalez-Aramundiz, Jose Vicente; Cordeiro, Ana Sara; Csaba, Nœmi; de la Fuente, Maria; Alonso, María José

2012-01-01

Vaccination has become one of the most important health interventions of our times, revolutionizing health care, and improving the quality of life and life expectancy of millions all over the world. In spite of this, vaccine research remains a vast field for innovation and improvement. Indeed, the shift towards the use of sub-unit antigens, much safer but less immunogenic, and the recognized need to facilitate the access to vaccines in the global framework is currently stimulating the search for safe and efficient adjuvants and delivery technologies. Within this context, nanocarriers have gained particular attention over the last years and appear as one of the most promising strategies for antigen delivery. A number of biomaterials and technologies can be used to design nanovaccines that fulfill the requirements of new vaccination approaches, such as single-dose and transmucosal immunization, critical for achieving a widespread coverage while reducing the overall costs in relation to traditional forms of vaccination. Here we present an overview of the current state of nanocarriers for antigen delivery, developed with the perspective of contributing to the global vaccination goal. © Société de Biologie, 2013.

Killed whole-HIV vaccine; employing a well established strategy for antiviral vaccines.

PubMed

Kang, C Yong; Gao, Yong

2017-09-12

The development of an efficient prophylactic HIV vaccine has been one of the major challenges in infectious disease research during the last three decades. Here, we present a mini review on strategies employed for the development of HIV vaccines with an emphasis on a well-established vaccine technology, the killed whole-virus vaccine approach. Recently, we reported an evaluation of the safety and the immunogenicity of a genetically modified and killed whole-HIV-1 vaccine designated as SAV001 [1]. HIV-1 Clade B NL4-3 was genetically modified by deleting the nef and vpu genes and substituting the coding sequence of the Env signal peptide with that of honeybee melittin to produce an avirulent and replication efficient HIV-1. This genetically modified virus (gmHIV-1 NL4-3 ) was propagated in a human T cell line followed by virus purification and inactivation by aldrithiol-2 and γ-irradiation. We found that SAV001 was well tolerated with no serious adverse events. HIV-1 NL4-3 -specific polymerase chain reaction showed no evidence of vaccine virus replication in participants receiving SAV001 and in human T cells infected in vitro. Furthermore, SAV001 with an adjuvant significantly increased the antibody response to HIV-1 structural proteins. Moreover, antibodies in the plasma from these vaccinations neutralized tier I and tier II of HIV-1 B, A, and D subtypes. These results indicated that the killed whole-HIV vaccine is safe and may trigger appropriate immune responses to prevent HIV infection. Utilization of this killed whole-HIV vaccine strategy may pave the way to develop an effective HIV vaccine.

Liposomal adjuvant development for leishmaniasis vaccines.

PubMed

Askarizadeh, Anis; Jaafari, Mahmoud Reza; Khamesipour, Ali; Badiee, Ali

2017-08-01

Leishmaniasis is a parasitic disease that ranges in severity from skin lesions to fatality. Since long-lasting protection is induced upon recovery from cutaneous leishmaniasis, development of an effective vaccine is promising. However, there is no vaccine for use in humans yet. It seems limited efficacy in leishmaniasis vaccines is due to lack of an appropriate adjuvant or delivery system. Hence, the use of particulate adjuvants such as liposomes for effective delivery to the antigen presenting cells (APCs) is a valuable strategy to enhance leishmaniasis vaccine efficacy. The extraordinary versatility of liposomes because of their unique amphiphilic and biphasic nature allows for using antigens or immunostimulators within the core, on the surface or within the bilayer, and modulates both the magnitude and the T-helper bias of the immune response. In this review article, we attempt to summarize the role of liposomal adjuvants in the development of Leishmania vaccines and describe the main physicochemical properties of liposomes like phospholipid composition, surface charge, and particle size during formulation design. We also suggest potentially useful formulation strategies in order for future experiments to have a chance to succeed as liposomal vaccines against leishmaniasis.

Liposomal adjuvant development for leishmaniasis vaccines

PubMed Central

Askarizadeh, Anis; Jaafari, Mahmoud Reza; Khamesipour, Ali; Badiee, Ali

2017-01-01

Leishmaniasis is a parasitic disease that ranges in severity from skin lesions to fatality. Since long-lasting protection is induced upon recovery from cutaneous leishmaniasis, development of an effective vaccine is promising. However, there is no vaccine for use in humans yet. It seems limited efficacy in leishmaniasis vaccines is due to lack of an appropriate adjuvant or delivery system. Hence, the use of particulate adjuvants such as liposomes for effective delivery to the antigen presenting cells (APCs) is a valuable strategy to enhance leishmaniasis vaccine efficacy. The extraordinary versatility of liposomes because of their unique amphiphilic and biphasic nature allows for using antigens or immunostimulators within the core, on the surface or within the bilayer, and modulates both the magnitude and the T-helper bias of the immune response. In this review article, we attempt to summarize the role of liposomal adjuvants in the development of Leishmania vaccines and describe the main physicochemical properties of liposomes like phospholipid composition, surface charge, and particle size during formulation design. We also suggest potentially useful formulation strategies in order for future experiments to have a chance to succeed as liposomal vaccines against leishmaniasis. PMID:29201374

Surface-Modified P(HEMA-co-MAA) Nanogel Carriers for Oral Vaccine Delivery: Design, Characterization, and In Vitro Targeting Evaluation

PubMed Central

Durán-Lobato, Matilde; Carrillo-Conde, Brenda; Khairandish, Yasmine; Peppas, Nicholas A.

2015-01-01

Oral drug delivery is a route of choice for vaccine administration because of its noninvasive nature and thus efforts have focused on efficient delivery of vaccine antigens to mucosal sites. An effective oral vaccine delivery system must protect the antigen from degradation upon mucosal delivery, penetrate mucosal barriers, and control the release of the antigen and costimulatory and immunomodulatory agents to specific immune cells (i.e., APCs). In this paper, mannan-modified pH-responsive P(HEMA-co-MAA) nanogels were synthesized and assessed as carriers for oral vaccination. The nanogels showed pH-sensitive properties, entrapping and protecting the loaded cargo at low pH values, and triggered protein release after switching to intestinal pH values. Surface decoration with mannan as carbohydrate moieties resulted in enhanced internalization by macrophages as well as increasing the expression of relevant costimulatory molecules. These findings indicate that mannan-modified P(HEMA-co-MAA) nanogels are a promising approach to a more efficacious oral vaccination regimen. PMID:24955658

Novel vaccine strategies against emerging viruses

PubMed Central

García-Sastre, Adolfo; Mena, Ignacio

2013-01-01

One of the main public health concerns of emerging viruses is their potential introduction into and sustained circulation among populations of immunologically naïve, susceptible hosts. The induction of protective immunity through vaccination can be a powerful tool to prevent this concern by conferring protection to the population at risk. Conventional approaches to develop vaccines against emerging pathogens have significant limitations: lack of experimental tools for several emerging viruses of concern, poor immunogenicity, safety issues, or lack of cross-protection against antigenic variants. The unpredictability of the emergence of future virus threats demands the capability to rapidly develop safe, effective vaccines. We describe some recent advances in new vaccine strategies that are being explored as alternatives to classical attenuated and inactivated vaccines, and provide examples of potential novel vaccines for emerging viruses. These approaches might be applied to the control of many other emerging pathogens. PMID:23477832

Cost-Effectiveness Analysis of Hepatitis B Vaccination Strategies to Prevent Perinatal Transmission in North Korea: Selective Vaccination vs. Universal Vaccination.

PubMed

Lee, Donghoon; Park, Sang Min

2016-01-01

To tackle the high prevalence of Hepatitis B virus (HBV) infection in North Korea, it is essential that birth doses of HBV vaccines should be administered within 24 hours of birth. As the country fails to provide a Timely Birth Dose (TBD) of HBV vaccine, the efforts of reducing the high prevalence of HBV have been significantly hampered. To examine the cost-effectiveness of vaccination strategies to prevent perinatal transmission of HBV in North Korea, we established a decision tree with a Markov model consisting of selective, universal, and the country's current vaccination program against HBV. The cost-effectiveness analysis was performed from societal and payer's perspectives and evaluated by Disability Adjusted Life Year (DALY). The results suggest that introducing the universal vaccination would prevent 1,866 cases of perinatal infections per 100,000 of the birth cohort of 2013. Furthermore, 900 cases of perinatal infections per 100,000 could be additionally averted if switching to the selective vaccination. The current vaccination is a dominated strategy both from the societal and payer's perspective. The Incremental Cost-Effectiveness Ratio (ICER) between universal and selective vaccination is $267 from the societal perspective and is reported as $273 from the payer's perspective. Based on the assumption that the 2012 Gross Domestic Product (GDP) per capita in North Korea, $582.6 was set for cost-effectiveness criteria, the result of this study indicates that selective vaccination may be a highly cost-effective strategy compared to universal vaccination.

Misinformation lingers in memory: Failure of three pro-vaccination strategies.

PubMed

Pluviano, Sara; Watt, Caroline; Della Sala, Sergio

2017-01-01

People's inability to update their memories in light of corrective information may have important public health consequences, as in the case of vaccination choice. In the present study, we compare three potentially effective strategies in vaccine promotion: one contrasting myths vs. facts, one employing fact and icon boxes, and one showing images of non-vaccinated sick children. Beliefs in the autism/vaccines link and in vaccines side effects, along with intention to vaccinate a future child, were evaluated both immediately after the correction intervention and after a 7-day delay to reveal possible backfire effects. Results show that existing strategies to correct vaccine misinformation are ineffective and often backfire, resulting in the unintended opposite effect, reinforcing ill-founded beliefs about vaccination and reducing intentions to vaccinate. The implications for research on vaccines misinformation and recommendations for progress are discussed.

Misinformation lingers in memory: Failure of three pro-vaccination strategies

PubMed Central

Pluviano, Sara

2017-01-01

People’s inability to update their memories in light of corrective information may have important public health consequences, as in the case of vaccination choice. In the present study, we compare three potentially effective strategies in vaccine promotion: one contrasting myths vs. facts, one employing fact and icon boxes, and one showing images of non-vaccinated sick children. Beliefs in the autism/vaccines link and in vaccines side effects, along with intention to vaccinate a future child, were evaluated both immediately after the correction intervention and after a 7-day delay to reveal possible backfire effects. Results show that existing strategies to correct vaccine misinformation are ineffective and often backfire, resulting in the unintended opposite effect, reinforcing ill-founded beliefs about vaccination and reducing intentions to vaccinate. The implications for research on vaccines misinformation and recommendations for progress are discussed. PMID:28749996

In situ pneumococcal vaccine production and delivery through a hybrid biological-biomaterial vector

PubMed Central

Li, Yi; Beitelshees, Marie; Fang, Lei; Hill, Andrew; Ahmadi, Mahmoud Kamal; Chen, Mingfu; Davidson, Bruce A.; Knight, Paul; Smith, Randall J.; Andreadis, Stelios T.; Hakansson, Anders P.; Jones, Charles H.; Pfeifer, Blaine A.

2016-01-01

The type and potency of an immune response provoked during vaccination will determine ultimate success in disease prevention. The basis for this response will be the design and implementation of antigen presentation to the immune system. Whereas direct antigen administration will elicit some form of immunological response, a more sophisticated approach would couple the antigen of interest to a vector capable of broad delivery formats and designed for heightened response. New antigens associated with pneumococcal disease virulence were used to test the delivery and adjuvant capabilities of a hybrid biological-biomaterial vector consisting of a bacterial core electrostatically coated with a cationic polymer. The hybrid design provides (i) passive and active targeting of antigen-presenting cells, (ii) natural and multicomponent adjuvant properties, (iii) dual intracellular delivery mechanisms, and (iv) a simple formulation mechanism. In addition, the hybrid format enables device-specific, or in situ, antigen production and consolidation via localization within the bacterial component of the vector. This capability eliminates the need for dedicated antigen production and purification before vaccination efforts while leveraging the aforementioned features of the overall delivery device. We present the first disease-specific utilization of the vector toward pneumococcal disease highlighted by improved immune responses and protective capabilities when tested against traditional vaccine formulations and a range of clinically relevant Streptococcus pneumoniae strains. More broadly, the results point to similar levels of success with other diseases that would benefit from the production, delivery, and efficacy capabilities offered by the hybrid vector. PMID:27419235

Characterization of guinea pig T cell responses elicited after EP-assisted delivery of DNA vaccines to the skin

PubMed Central

Schultheis, Katherine; Schaefer, Hubert; Yung, Bryan S.; Oh, Janet; Muthumani, Karuppiah; Humeau, Laurent; Broderick, Kate E.

2016-01-01

The skin is an ideal target tissue for vaccine delivery for a number of reasons. It is highly accessible, and most importantly, enriched in professional antigen presenting cells. Possessing strong similarities to human skin physiology and displaying a defined epidermis, the guinea pig is an appropriate model to study epidermal delivery of vaccine. However, whilst we have characterized the humoral responses in the guinea pig associated with skin vaccine protocols we have yet to investigate the T cell responses. In response to this inadequacy, we developed an IFN-γ ELISpot assay to characterize the cellular immune response in the peripheral blood of guinea pigs. Using a nucleoprotein (NP) influenza pDNA vaccination regimen, we characterized host T cell responses. After delivery of the DNA vaccine to the guinea pig epidermis we detected robust and rapid T cell responses. The levels of IFN-γ spot-forming units averaged approximately 5000 per million cells after two immunizations. These responses were broad in that multiple regions across the NP antigen elicited a T cell response. Interestingly, we identified a number of NP immunodominant T cell epitopes to be conserved across an outbred guinea pig population, a phenomenon which was also observed after immunization with a RSV DNA vaccine. We believe this data enhances our understanding of the cellular immune response elicited to a vaccine in guinea pigs, and globally, will advance the use of this model for vaccine development, especially those targeting skin as a delivery site. PMID:27894716

Immune response in domestic ducks following intradermal delivery of inactivated vaccine against H5N1 highly pathogenic avian influenza virus adjuvanted with oligodeoxynucleotides containing CpG motifs.

PubMed

Yuk, Seong-Su; Lee, Dong-Hun; Park, Jae-Keun; To, Eredene-Ochir; Kwon, Jung-Hoon; Noh, Jin-Yong; Gomis, Susantha; Song, Chang-Seon

2015-08-01

Ducks are a natural reservoir for H5N1 highly pathogenic avian influenza (HPAI) viruses, which produces a range of clinical outcomes from asymptomatic infections to severe disease with mortality. Vaccination against HPAI is one of the few methods available for controlling avian influenza virus (AIV) infection in domestic ducks; therefore, it is necessary to improve vaccine efficacy against HPAI in domestic ducks. However, few studies have focused on enhancing the immune response by testing alternative administration routes and adjuvants. While attempting to maximize the efficacy of a vaccine, it is important to select an appropriate vaccine delivery route and adjuvant to elicit an enhanced immune response. Although several studies have indicated that the vaccination of ducks against HPAI viruses has offered protection against lethal virus challenge, the immunogenicity of the vaccine still requires improvement. In this study, we characterized the immune response following a novel vaccination strategy against H5N1 HPAI virus in domestic ducks. Our novel intradermal delivery system and the application of the cytosine-phosphodiester-guanine (CpG) oligodeoxynucleotide (ODN) adjuvant allowed us to obtain information regarding the sustained vaccine immunity. Compared with the intramuscular route of vaccination, the intradermal route resulted in higher antibody titer as well as lower antibody deviation following secondary vaccination. In addition, the use of a CpG-ODN adjuvant had a dose-sparing effect on antibody titer. Furthermore, when a high dose of antigen was used, the CpG-ODN-adjuvanted vaccine maintained a high mean antibody titer. This data demonstrates that intradermal immunization combined with administration of CpG-ODN as an adjuvant may be a promising strategy for improving vaccine efficacy in domestic ducks. © 2015 Poultry Science Association Inc.

Oral delivery of human biopharmaceuticals, autoantigens and vaccine antigens bioencapsulated in plant cells

PubMed Central

Kwon, Kwang-Chul; Verma, Dheeraj; Singh, Nameirakpam D.; Herzog, Roland; Daniell, Henry

2012-01-01

Among 12 billion injections administered annually, unsafe delivery leads to >20 million infections and >100 million reactions. In an emerging new concept, freeze-dried plant cells (lettuce) expressing vaccine antigens/biopharmaceuticals are protected in the stomach from acids/enzymes but are released to the immune or blood circulatory system when plant cell walls are digested by microbes that colonize the gut. Vaccine antigens bioencapsulated in plant cells upon oral delivery after priming, conferred both mucosal and systemic immunity and protection against bacterial, viral or protozoan pathogens or toxin challenge. Oral delivery of autoantigens was effective against complications of type 1diabetes and hemophilia, by developing tolerance. Oral delivery of proinsulin or exendin-4 expressed in plant cells regulated blood glucose levels similar to injections. Therefore, this new platform offers a low cost alternative to deliver different therapeutic proteins to combat infectious or inherited diseases by eliminating inactivated pathogens, expensive purification, cold storage/transportation and sterile injections. PMID:23099275

Using hepatitis A and B vaccination as a paradigm for effective HIV vaccine delivery.

PubMed

Rhodes, Scott D; Yee, Leland J

2007-06-01

An understanding of vaccine acceptance and uptake is imperative for successful vaccination of populations that will be primary targets for vaccination after a vaccine against HIV is developed and ready for dissemination. Experiences with vaccination against vaccine-preventable hepatitis (VPH) among men who have sex with men (MSM) may offer key insights to inform future HIV vaccination strategies. The purpose of this analysis was to explore what is known currently about vaccination among MSM, using knowledge gained from vaccination against VPH, and to identify important considerations from these experiences that must be explored further as a vaccine against HIV is promoted among MSM. Because cultural and political differences make it difficult to extrapolate findings from studies in one country to another, we have focused our analyses on studies conducted in the USA. Through a qualitative systematic review of published reports, we identified eight studies that reported correlates of VPH among MSM in the USA. Six major domains of variables associated with vaccination against VPH were identified, including: demographics (e.g. younger age, higher educational attainment); increased vaccine knowledge; increased access to health care; provider recommendation; behaviours (e.g. same-sex behaviour, health-promoting and disease-preventing behaviours); and psychosocial factors (e.g. openness about one's sexual orientation, reduced barriers to being vaccinated, self-efficacy). Further research is needed to understand vaccination behaviour among MSM and to maximise acceptance and uptake after a vaccine exists. Experiences with VPH provide a real-world model on which to base preliminary assumptions about acceptance and uptake of a vaccine against HIV.

Costs of vaccine delivery in the Gambia before and after, pentavalent and pneumococcal conjugate vaccine introductions.

PubMed

Usuf, E; Mackenzie, G; Lowe-Jallow, Y; Boye, B; Atherly, D; Suraratdecha, C; Griffiths, U K

2014-04-07

The Gambia introduced seven-valent pneumococcal conjugate vaccine (PCV) in August 2009 and switched to 13-valent PCV in April 2011. In April 2009 monovalent hepatitis B and combined Diphtheria-Tetanus-Pertussis and Haemophilus influenzae type b vaccines were transitioned to a combined pentavalent vaccine. The current schedule offers three doses of PCV and pentavalent, and continues to give children monovalent hepatitis B vaccine at birth. We estimated the overall costs of the Gambian immunisation programme and the incremental costs of introducing pentavalent and the seven-valent PCV. Twenty health facilities out of a total of 56 were surveyed. Data collected included number of vaccine doses delivered, staff time spent on vaccine delivery, distance travelled to collect vaccines, and cold chain expansion due to new vaccine introduction. National level data were collected from key informant interviews. Annualised costs were calculated in 2009 US$. With a PCV price of US$7 per dose, the incremental costs of introducing PCV was US$1.6 million, equivalent to US$25 per fully immunised child, with systems costs accounting for US$1.90. The switch to pentavalent vaccine resulted in cost savings of US$0.45 per fully immunised child. Total annual costs increased by 45% after the introduction of the new vaccines, amounting to US$ 3.0 million, or US$45 per fully immunised child. Vaccine prices were the most important determinant of total incremental costs and cold chain expansion the biggest cost component of systems costs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pathogen-mimicking vaccine delivery system designed with a bioactive polymer (inulin acetate) for robust humoral and cellular immune responses.

PubMed

Kumar, Sunny; Kesharwani, Siddharth S; Kuppast, Bhimanna; Bakkari, Mohammed Ali; Tummala, Hemachand

2017-09-10

New and improved vaccines are needed against challenging diseases such as malaria, tuberculosis, Ebola, influenza, AIDS, and cancer. The majority of existing vaccine adjuvants lack the ability to significantly stimulate the cellular immune response, which is required to prevent the aforementioned diseases. This study designed a novel particulate based pathogen-mimicking vaccine delivery system (PMVDS) to target antigen-presenting-cells (APCs) such as dendritic cells. The uniqueness of PMVDS is that the polymer used to prepare the delivery system, Inulin Acetate (InAc), activates the innate immune system. InAc was synthesized from the plant polysaccharide, inulin. PMVDS provided improved and persistent antigen delivery to APCs as an efficient vaccine delivery system, and simultaneously, activated Toll-Like Receptor-4 (TLR-4) on APCs to release chemokine's/cytokines as an immune-adjuvant. Through this dual mechanism, PMVDS robustly stimulated both the humoral (>32 times of IgG1 levels vs alum) and the cell-mediated immune responses against the encapsulated antigen (ovalbumin) in mice. More importantly, PMVDS stimulated both cytotoxic T cells and natural killer cells of cell-mediated immunity to provide tumor (B16-ova-Melanoma) protection in around 40% of vaccinated mice and significantly delayed tumor progression in rest of the mice. PMVDS is a unique bio-active vaccine delivery technology with broader applications for vaccines against cancer and several intracellular pathogens, where both humoral and cellular immune responses are desired. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of Strategies and Incidence Thresholds for Vi Conjugate Vaccines Against Typhoid Fever: A Cost-effectiveness Modeling Study.

PubMed

Lo, Nathan C; Gupta, Ribhav; Stanaway, Jeffrey D; Garrett, Denise O; Bogoch, Isaac I; Luby, Stephen P; Andrews, Jason R

2018-02-12

Typhoid fever remains a major public health problem globally. While new Vi conjugate vaccines hold promise for averting disease, the optimal programmatic delivery remains unclear. We aimed to identify the strategies and associated epidemiologic conditions under which Vi conjugate vaccines would be cost-effective. We developed a dynamic, age-structured transmission and cost-effectiveness model that simulated multiple vaccination strategies with a typhoid Vi conjugate vaccine from a societal perspective. We simulated 10-year vaccination programs with (1) routine immunization of infants (aged <1 year) through the Expanded Program on Immunization (EPI) and (2) routine immunization of infants through the EPI plus a 1-time catch-up campaign in school-aged children (aged 5-14 years). In the base case analysis, we assumed a 0.5% case-fatality rate for all cases of clinically symptomatic typhoid fever and defined strategies as highly cost-effective by using the definition of a low-income country (defined as a country with a gross domestic product of $1045 per capita). We defined incidence as the true number of clinically symptomatic people in the population per year. Vi conjugate typhoid vaccines were highly cost-effective when administered by routine immunization activities through the EPI in settings with an annual incidence of >50 cases/100000 (95% uncertainty interval, 40-75 cases) and when administered through the EPI plus a catch-up campaign in settings with an annual incidence of >130 cases/100000 (95% uncertainty interval, 50-395 cases). The incidence threshold was sensitive to the typhoid-related case-fatality rate, carrier contribution to transmission, vaccine characteristics, and country-specific economic threshold for cost-effectiveness. Typhoid Vi conjugate vaccines would be highly cost-effective in low-income countries in settings of moderate typhoid incidence (50 cases/100000 annually). These results were sensitive to case-fatality rates, underscoring the

Severe post-vaccination reaction to 17D yellow fever vaccine in Nigeria.

PubMed

Oyelami, S A; Olaleye, O D; Oyejide, C O; Omilabu, S A; Fatunla, B A

1994-01-01

An unusual outbreak of post-vaccination reactions to 17D yellow fever vaccine occurred at Shaki, Nigeria, in May 1987. Twenty-five of the affected people were treated at the Baptist Hospital Shaki. The patients presented with rapidly progressing swelling of the left arm with associated fever and other constitutional symptoms few hours after inoculation with the vaccine. Some of the patients developed gangrene of the affected limb, five of them went into coma and died. Poor hygiene and improper handling of vaccine as well as contamination of vaccine from the source are possible causes. A review of vaccine delivery strategies especially at local community levels; sound training, supervision of vaccinators and health education are strongly recommended to prevent reoccurrence of similar reactions.

Lactococci and lactobacilli as mucosal delivery vectors for therapeutic proteins and DNA vaccines

PubMed Central

2011-01-01

Food-grade Lactic Acid Bacteria (LAB) have been safely consumed for centuries by humans in fermented foods. Thus, they are good candidates to develop novel oral vectors, constituting attractive alternatives to attenuated pathogens, for mucosal delivery strategies. Herein, this review summarizes our research, up until now, on the use of LAB as mucosal delivery vectors for therapeutic proteins and DNA vaccines. Most of our work has been based on the model LAB Lactococcus lactis, for which we have developed efficient genetic tools, including expression signals and host strains, for the heterologous expression of therapeutic proteins such as antigens, cytokines and enzymes. Resulting recombinant lactococci strains have been tested successfully for their prophylactic and therapeutic effects in different animal models: i) against human papillomavirus type 16 (HPV-16)-induced tumors in mice, ii) to partially prevent a bovine β-lactoglobulin (BLG)-allergic reaction in mice and iii) to regulate body weight and food consumption in obese mice. Strikingly, all of these tools have been successfully transposed to the Lactobacillus genus, in recent years, within our laboratory. Notably, anti-oxidative Lactobacillus casei strains were constructed and tested in two chemically-induced colitis models. In parallel, we also developed a strategy based on the use of L. lactis to deliver DNA at the mucosal level, and were able to show that L. lactis is able to modulate the host response through DNA delivery. Today, we consider that all of our consistent data, together with those obtained by other groups, demonstrate and reinforce the interest of using LAB, particularly lactococci and lactobacilli strains, to develop novel therapeutic protein mucosal delivery vectors which should be tested now in human clinical trials. PMID:21995317

[Strategies to improve influenza vaccination coverage in Primary Health Care].

PubMed

Antón, F; Richart, M J; Serrano, S; Martínez, A M; Pruteanu, D F

2016-04-01

Vaccination coverage reached in adults is insufficient, and there is a real need for new strategies. To compare strategies for improving influenza vaccination coverage in persons older than 64 years. New strategies were introduced in our health care centre during 2013-2014 influenza vaccination campaign, which included vaccinating patients in homes for the aged as well as in the health care centre. A comparison was made on vaccination coverage over the last 4 years in 3 practices of our health care centre: P1, the general physician vaccinated patients older than 64 that came to the practice; P2, the general physician systematically insisted in vaccination in elderly patients, strongly advising to book appointments, and P3, the general physician did not insist. These practices looked after P1: 278; P2: 320; P3: 294 patients older than 64 years. Overall/P1/P2/P3 coverages in 2010: 51.2/51.4/55/46.9% (P=NS), in 2011: 52.4/52.9/53.8/50.3% (P=NS), in 2012: 51.9/52.5/55.3/47.6% (P=NS), and in 2013: 63.5/79.1/59.7/52.7 (P=.000, P1 versus P2 and P3; P=NS between P2 and P3). Comparing the coverages in 2012-2013 within each practice P1 (P=.000); P2 (P=.045); P3 (P=.018). In P2 and P3 all vaccinations were given by the nurses as previously scheduled. In P3, 55% of the vaccinations were given by the nurses, 24.1% by the GP, 9.7% rejected vaccination, and the remainder did not come to the practice during the vaccination period (October 2013-February 2014). The strategy of vaccinating in the homes for the aged improved the vaccination coverage by 5% in each practice. The strategy of "I've got you here, I jab you here" in P1 improved the vaccination coverage by 22%. Copyright © 2014 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España, S.L.U. All rights reserved.

Cost-Effectiveness Analysis of Hepatitis B Vaccination Strategies to Prevent Perinatal Transmission in North Korea: Selective Vaccination vs. Universal Vaccination

PubMed Central

Lee, Donghoon; Park, Sang Min

2016-01-01

Background To tackle the high prevalence of Hepatitis B virus (HBV) infection in North Korea, it is essential that birth doses of HBV vaccines should be administered within 24 hours of birth. As the country fails to provide a Timely Birth Dose (TBD) of HBV vaccine, the efforts of reducing the high prevalence of HBV have been significantly hampered. Methods To examine the cost-effectiveness of vaccination strategies to prevent perinatal transmission of HBV in North Korea, we established a decision tree with a Markov model consisting of selective, universal, and the country’s current vaccination program against HBV. The cost-effectiveness analysis was performed from societal and payer’s perspectives and evaluated by Disability Adjusted Life Year (DALY). Results The results suggest that introducing the universal vaccination would prevent 1,866 cases of perinatal infections per 100,000 of the birth cohort of 2013. Furthermore, 900 cases of perinatal infections per 100,000 could be additionally averted if switching to the selective vaccination. The current vaccination is a dominated strategy both from the societal and payer’s perspective. The Incremental Cost-Effectiveness Ratio (ICER) between universal and selective vaccination is $267 from the societal perspective and is reported as $273 from the payer’s perspective. Conclusion Based on the assumption that the 2012 Gross Domestic Product (GDP) per capita in North Korea, $582.6 was set for cost-effectiveness criteria, the result of this study indicates that selective vaccination may be a highly cost-effective strategy compared to universal vaccination. PMID:27802340

A novel "in-feed" delivery platform applied for oral DNA vaccination against IPNV enables high protection in Atlantic salmon (Salmon salar).

PubMed

Reyes, Miguel; Ramírez, Cesar; Ñancucheo, Ivan; Villegas, Ricardo; Schaffeld, Guillermo; Kriman, Luis; Gonzalez, Javier; Oyarzun, Patricio

2017-01-23

DNA vaccination has emerged as a promising tool against infectious diseases of farmed fish. Oral delivery allows stress-free administration that is ideal for mass immunization and of paramount importance for infectious pancreatic necrosis (IPN) and other viral disease that affect young salmonids and cause economic losses in aquaculture worldwide. We describe the development and in vivo assessment of an "in-feed" formulation strategy for oral immunization with liposomal DNA vaccines, by delivering a vaccine construct coding for an immunogenic region of the VP2 capsid protein. A challenge against IPNV was carried out to determine the vaccine efficacy, by comparing the mortality of pre-smolt Atlantic salmons immunized and non-immunized with the oral vaccine. The antibody response (ELISA) and hematological parameters after immunization were examined, as well as the vaccine effect on the growth and internal structures of fry salmons (histological analysis). The vaccine distribution in the experimental tank after oral administration was investigated by HPLC and PCR amplification. The oral vaccine induced detectable levels of VP2-specific antibodies and conferred significant protection following IPNV challenge, with relative percent survivals (RPS) of 58.2%, for single dose (1mg pDNA /kg fish ⋅d), and 66% for double dose (2mg pDNA /kg fish ⋅d). We further provide evidence in favour of the vaccine safety to fish and demonstrated absence of pDNA in the tank water, but presence of vaccine residues in faeces and unconsumed feed sediments (solid wastes). The delivery platform for liposomal DNA vaccination via feed was successfully proved against IPNV in Atlantic salmon, showing the oral vaccine to be immunogenic and safe for fish, and providing significant protection after oral administration. The "in-feed" technology for oral DNA vaccination holds potential to be applied against IPNV and other pathogens that currently threaten the aquaculture worldwide. Copyright © 2016

Anti-cancer vaccination by transdermal delivery of antigen peptide-loaded nanogels via iontophoresis.

PubMed

Toyoda, Mao; Hama, Susumu; Ikeda, Yutaka; Nagasaki, Yukio; Kogure, Kentaro

2015-04-10

Transdermal vaccination with cancer antigens is expected to become a useful anti-cancer therapy. However, it is difficult to accumulate enough antigen in the epidermis for effective exposure to Langerhans cells because of diffusion into the skin and muscle. Carriers, such as liposomes and nanoparticles, may be useful for the prevention of antigen diffusion. Iontophoresis, via application of a small electric current, is a noninvasive and efficient technology for transdermal drug delivery. Previously, we succeeded in the iontophoretic transdermal delivery of liposomes encapsulating insulin, and accumulation of polymer-based nanoparticle nanogels in the stratum corneum of the skin. Therefore, in the present study, we examined the use of iontophoresis with cancer antigen gp-100 peptide KVPRNQDWL-loaded nanogels for anti-cancer vaccination. Iontophoresis resulted in the accumulation of gp-100 peptide and nanogels in the epidermis, and subsequent increase in the number of Langerhans cells in the epidermis. Moreover, tumor growth was significantly suppressed by iontophoresis of the antigen peptide-loaded nanogels. Thus, iontophoresis of the antigen peptide-loaded nanogels may serve as an effective transdermal delivery system for anti-cancer vaccination. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of Mucosal and Systemic Immune Responses Elicited by GPI-0100- Adjuvanted Influenza Vaccine Delivered by Different Immunization Strategies

PubMed Central

Liu, Heng; Patil, Harshad P.; de Vries-Idema, Jacqueline; Wilschut, Jan; Huckriede, Anke

2013-01-01

Vaccines for protection against respiratory infections should optimally induce a mucosal immune response in the respiratory tract in addition to a systemic immune response. However, current parenteral immunization modalities generally fail to induce mucosal immunity, while mucosal vaccine delivery often results in poor systemic immunity. In order to find an immunization strategy which satisfies the need for induction of both mucosal and systemic immunity, we compared local and systemic immune responses elicited by two mucosal immunizations, given either by the intranasal (IN) or the intrapulmonary (IPL) route, with responses elicited by a mucosal prime followed by a systemic boost immunization. The study was conducted in BALB/c mice and the vaccine formulation was an influenza subunit vaccine supplemented with GPI-0100, a saponin-derived adjuvant. While optimal mucosal antibody titers were obtained after two intrapulmonary vaccinations, optimal systemic antibody responses were achieved by intranasal prime followed by intramuscular boost. The latter strategy also resulted in the best T cell response, yet, it was ineffective in inducing nose or lung IgA. Successful induction of secretory IgA, IgG and T cell responses was only achieved with prime-boost strategies involving intrapulmonary immunization and was optimal when both immunizations were given via the intrapulmonary route. Our results underline that immunization via the lungs is particularly effective for priming as well as boosting of local and systemic immune responses. PMID:23936066

Multilayer engineered nanoliposomes as a novel tool for oral delivery of lipopeptide-based vaccines against group A Streptococcus.

PubMed

Marasini, Nirmal; Giddam, Ashwini K; Ghaffar, Khairunnisa A; Batzloff, Michael R; Good, Michael F; Skwarczynski, Mariusz; Toth, Istvan

2016-05-01

To develop an oral nanovaccine delivery system for lipopeptide-based vaccine candidate against group A Streptococcus. Lipid-core peptide-1-loaded nanoliposomes were prepared as a template and coated with opposite-charged polyelectrolytes to produce particles with size <200 nm. Efficacy of this oral nanovaccine delivery system was evaluated in mice model. Polymer-coated liposomes produced significantly higher antigen-specific mucosal IgA and systemic IgG titers in comparison to vaccine formulated with a strong mucosal adjuvant upon oral immunization in mice. Moreover, high levels of systemic antibody titers were retained even at day 185 postprimary immunization. Efficient oral delivery platform for lipopeptide-based vaccines has been developed.

Dissolving and biodegradable microneedle technologies for transdermal sustained delivery of drug and vaccine

PubMed Central

Hong, Xiaoyun; Wei, Liangming; Wu, Fei; Wu, Zaozhan; Chen, Lizhu; Liu, Zhenguo; Yuan, Weien

2013-01-01

Microneedles were first conceptualized for drug delivery many decades ago, overcoming the shortages and preserving the advantages of hypodermic needle and conventional transdermal drug-delivery systems to some extent. Dissolving and biodegradable microneedle technologies have been used for transdermal sustained deliveries of different drugs and vaccines. This review describes microneedle geometry and the representative dissolving and biodegradable microneedle delivery methods via the skin, followed by the fabricating methods. Finally, this review puts forward some perspectives that require further investigation. PMID:24039404

Characterization of guinea pig T cell responses elicited after EP-assisted delivery of DNA vaccines to the skin.

PubMed

Schultheis, Katherine; Schaefer, Hubert; Yung, Bryan S; Oh, Janet; Muthumani, Karuppiah; Humeau, Laurent; Broderick, Kate E; Smith, Trevor R F

2017-01-03

The skin is an ideal target tissue for vaccine delivery for a number of reasons. It is highly accessible, and most importantly, enriched in professional antigen presenting cells. Possessing strong similarities to human skin physiology and displaying a defined epidermis, the guinea pig is an appropriate model to study epidermal delivery of vaccine. However, whilst we have characterized the humoral responses in the guinea pig associated with skin vaccine protocols we have yet to investigate the T cell responses. In response to this inadequacy, we developed an IFN-γ ELISpot assay to characterize the cellular immune response in the peripheral blood of guinea pigs. Using a nucleoprotein (NP) influenza pDNA vaccination regimen, we characterized host T cell responses. After delivery of the DNA vaccine to the guinea pig epidermis we detected robust and rapid T cell responses. The levels of IFN-γ spot-forming units averaged approximately 5000 per million cells after two immunizations. These responses were broad in that multiple regions across the NP antigen elicited a T cell response. Interestingly, we identified a number of NP immunodominant T cell epitopes to be conserved across an outbred guinea pig population, a phenomenon which was also observed after immunization with a RSV DNA vaccine. We believe this data enhances our understanding of the cellular immune response elicited to a vaccine in guinea pigs, and globally, will advance the use of this model for vaccine development, especially those targeting skin as a delivery site. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Vaccine decision-making begins in pregnancy: Correlation between vaccine concerns, intentions and maternal vaccination with subsequent childhood vaccine uptake.

PubMed

Danchin, M H; Costa-Pinto, J; Attwell, K; Willaby, H; Wiley, K; Hoq, M; Leask, J; Perrett, K P; O'Keefe, Jacinta; Giles, M L; Marshall, H

2017-08-12

Maternal and childhood vaccine decision-making begins prenatally. Amongst pregnant Australian women we aimed to ascertain vaccine information received, maternal immunisation uptake and attitudes and concerns regarding childhood vaccination. We also aimed to determine any correlation between a) intentions and concerns regarding childhood vaccination, (b) concerns about pregnancy vaccination, (c) socioeconomic status (SES) and (d) uptake of influenza and pertussis vaccines during pregnancy and routine vaccines during childhood. Women attending public antenatal clinics were recruited in three Australian states. Surveys were completed on iPads. Follow-up phone surveys were done three to six months post delivery, and infant vaccination status obtained via the Australian Childhood Immunisation Register (ACIR). Between October 2015 and March 2016, 975 (82%) of 1184 mothers consented and 406 (42%) agreed to a follow up survey, post delivery. First-time mothers (445; 49%) had significantly more vaccine concerns in pregnancy and only 73% had made a decision about childhood vaccination compared to 89% of mothers with existing children (p-value<0.001). 66% of mothers reported receiving enough information during pregnancy on childhood vaccination. In the post delivery survey, 46% and 82% of mothers reported receiving pregnancy influenza and pertussis vaccines respectively. The mother's degree of vaccine hesitancy and two attitudinal factors were correlated with vaccine uptake post delivery. There was no association between reported maternal vaccine uptake or SES and childhood vaccine uptake. First time mothers are more vaccine hesitant and undecided about childhood vaccination, and only two thirds of all mothers believed they received enough information during pregnancy. New interventions to improve both education and communication on childhood and maternal vaccines, delivered by midwives and obstetricians in the Australian public hospital system, may reduce vaccine hesitancy

Intranasal delivery of a protein subunit vaccine using a Tobacco Mosaic Virus platform protects against pneumonic plague.

PubMed

Arnaboldi, Paul M; Sambir, Mariya; D'Arco, Christina; Peters, Lauren A; Seegers, Jos F M L; Mayer, Lloyd; McCormick, Alison A; Dattwyler, Raymond J

2016-11-11

Yersinia pestis, one of history's deadliest pathogens, has killed millions over the course of human history. It has attributes that make it an ideal choice to produce mass casualties and is a prime candidate for use as a biological weapon. When aerosolized, Y. pestis causes pneumonic plague, a pneumonia that is 100% lethal if not promptly treated with effective antibiotics. Currently, there is no FDA approved plague vaccine. The current lead vaccine candidate, a parenterally administered protein subunit vaccine comprised of the Y. pestis virulence factors, F1 and LcrV, demonstrated variable levels of protection in primate pneumonic plague models. As the most likely mode of exposure in biological attack with Y. pestis is by aerosol, this raises a question of whether this parenteral vaccine will adequately protect humans against pneumonic plague. In the present study we evaluated two distinct mucosal delivery platforms for the intranasal (IN) administration of LcrV and F1 vaccine proteins, a live bacterial vector, Lactobacillus plantarum, and a Tobacco Mosaic Virus (TMV) based delivery platform. IN administration of L. plantarum expressing LcrV, or TMV-conjugated to LcrV and F1 (TMV-LcrV+TMV-F1) resulted in the similar induction of high titers of IgG antibodies and evidence of proinflammatory cytokine secretion. However, only the TMV-conjugate delivery platform protected against subsequent lethal challenge with Y. pestis. TMV-LcrV+TMV-F1 co-vaccinated mice had no discernable morbidity and no mortality, while mice vaccinated with L. plantarum expressing LcrV or rLcrV+rF1 without TMV succumbed to infection or were only partially protected. Thus, TMV is a suitable mucosal delivery platform for an F1-LcrV subunit vaccine that induces complete protection against pneumonic infection with a lethal dose of Y. pestis in mice. Copyright © 2016 Elsevier Ltd. All rights reserved.

The green vaccine: A global strategy to combat infectious and autoimmune diseases

PubMed Central

Davoodi-Semiromi, Abdoreza; Samson, Nalapalli; Daniell, Henry

2009-01-01

Plant derived oral green vaccines eliminate expenses associated with fermenters, purification, cold storage/transportation and sterile delivery. Green vaccines are expressed via the plant nuclear or chloroplast genomes. Chloroplast expression has advantages of hyper-expression of therapeutic proteins (10,000 copies of trans-gene per cell), efficient oral delivery and transgene containment via maternal inheritance. To date, 23 vaccine antigens against 16 different bacterial, viral or protozoan pathogens have been expressed in chloroplasts. Mice subcutaneously immunized with the chloroplast derived anthrax protective antigen conferred 100% protection against lethal doses of the anthrax toxin. Oral immunization (ORV) of F1-V antigens without adjuvant conferred greater protection (88%) against 50-fold lethal dose of aerosolized plague (Yersinia pestis) than subcutaneous (SQV) immunization (33%). Oral immunization of malarial vaccine antigens fused to the cholera antigen (CTB-AMA1/CTB-Msp1) conferred prolonged immunity (50% life span), 100% protection against cholera toxin challenge and inhibited proliferation of the malarial parasite. Protection was correlated with antigen-specific titers of intestinal, serum IgA & IgG1 in ORV and only IgG1 in SQV mice, but no other immunoglobulin. High level expression in edible plant chloroplasts ideal for oral delivery and long-term immunity observed should facilitate development of low cost human vaccines for large populations, at times of outbreak. PMID:19430198

Needle-free jet injector intradermal delivery of fractional dose inactivated poliovirus vaccine: Association between injection quality and immunogenicity.

PubMed

Resik, Sonia; Tejeda, Alina; Mach, Ondrej; Sein, Carolyn; Molodecky, Natalie; Jarrahian, Courtney; Saganic, Laura; Zehrung, Darin; Fonseca, Magile; Diaz, Manuel; Alemany, Nilda; Garcia, Gloria; Hung, Lai Heng; Martinez, Yenisleydis; Sutter, Roland W

2015-10-26

The World Health Organization recommends that as part of the polio end-game strategy a dose of inactivated poliovirus vaccine (IPV) be introduced by the end of 2015 in all countries currently using only oral poliovirus vaccine (OPV). Administration of fractional dose (1/5 of full dose) IPV (fIPV) by intradermal (ID) injection may reduce costs, but its conventional administration is with Bacillus Calmette-Guerin (BCG) needle and syringe (NS), which is time consuming and technically challenging. We compared injection quality achieved with BCG NS and three needle-free jet injectors and assessed ergonomic features of the injectors. Children between 12 and 20 months of age who had previously received OPV were enrolled in the Camaguey, Cuba study. Subjects received a single fIPV dose administered intradermally with BCG NS or one of three needle-free injector devices: Bioject Biojector 2000® (B2000), Bioject ID Pen® (ID Pen), or PharmaJet Tropis® (Tropis). We measured bleb diameter and vaccine loss as indicators of ID injection quality, with desirable injection quality defined as bleb diameter ≥5mm and vaccine loss <10%. We surveyed vaccinators to evaluate ergonomic features of the injectors. We further assessed the injection quality indicators as predictors of immune response, measured by increase in poliovirus neutralizing antibodies in blood between day 0 (pre-IPV) and 21 (post-vaccination). Delivery by BCG NS and Tropis resulted in the highest proportion of subjects with desirable injection quality; health workers ranked Biojector2000 and Tropis highest for ergonomic features. We observed that vaccine loss and desirable injection quality were associated with an immune response for poliovirus type 2 (P=0.02, P=0.01, respectively). Our study demonstrated the feasibility of fIPV delivery using needle-free injector devices with high acceptability among health workers. We did not observe the indicators of injection quality to be uniformly associated with immune

Degradable polymeric nano-films and particles as delivery platforms for vaccines and immunotherapeutics

NASA Astrophysics Data System (ADS)

Su, Xingfang

Degradable polymeric materials provide opportunities for the development of improved vaccines and immunotherapies by acting as platforms that facilitate the delivery of molecules to appropriate tissue and cellular locations to achieve therapeutic outcomes. To this end, we have designed and characterized nano-films and particles employing a hydrolytically degradable polymer for the delivery of vaccine antigens and immunotherapeutics. We first describe protein- and oligonucleotide-loaded layer-by-layer (LbL)-assembled multilayer thin films constructed based on electrostatic interactions between a cationic poly(beta-amino ester) (PBAE, denoted Poly-1) with a model protein antigen, ovalbumin (OVA), and/or immunostimulatory CpG oligonucleotides for transcutaneous delivery. Linear growth of nanoscale Poly-I/OVA bilayers was observed. Dried OVA protein-loaded films rapidly deconstructed when rehydrated in saline solutions, releasing OVA as non-aggregated/non-degraded protein, suggesting that the structure of biomolecules integrated into these multilayer films are preserved during release. Using confocal fluorescence microscopy and an in vivo murine ear skin model, we demonstrated delivery of OVA from LbL films into barrier-disrupted skin, uptake of the protein by skin-resident antigen-presenting cells (Langerhans cells), and transport of the antigen to the skin-draining lymph nodes. Dual incorporation of OVA and CpG oligonucleotides into the nanolayers of LbL films enabled dual release of the antigen and adjuvant with distinct kinetics for each component; OVA was rapidly released while CpG was released in a relatively sustained manner. Applied as skin patches, these films delivered OVA and CpG to Langerhans Cells in the skin. To our knowledge, this is the first demonstration of LbL films applied for the delivery of biomolecules into skin. This approach provides a new route for storage of vaccines and other immunotherapeutics in a solid-state thin film for subsequent

Estimating the costs of the vaccine supply chain and service delivery for selected districts in Kenya and Tanzania.

PubMed

Mvundura, Mercy; Lorenson, Kristina; Chweya, Amos; Kigadye, Rosemary; Bartholomew, Kathryn; Makame, Mohammed; Lennon, T Patrick; Mwangi, Steven; Kirika, Lydia; Kamau, Peter; Otieno, Abner; Murunga, Peninah; Omurwa, Tom; Dafrossa, Lyimo; Kristensen, Debra

2015-05-28

Having data on the costs of the immunization system can provide decision-makers with information to benchmark the costs when evaluating the impact of new technologies or programmatic innovations. This paper estimated the supply chain and immunization service delivery costs and cost per dose in selected districts in Kenya and Tanzania. We also present operational data describing the supply chain and service delivery points (SDPs). To estimate the supply chain costs, we collected resource-use data for the cold chain, distribution system, and health worker time and per diems paid. We also estimated the service delivery costs, which included the time cost of health workers to provide immunization services, and per diems and transport costs for outreach sessions. Data on the annual quantities of vaccines distributed to each facility, and the occurrence and duration of stockouts were collected from stock registers. These data were collected from the national store, 2 regional and 4 district stores, and 12 SDPs in each country for 2012. Cost per dose for the supply chain and immunization service delivery were estimated. The average annual costs per dose at the SDPs were $0.34 (standard deviation (s.d.) $0.18) for Kenya when including only the vaccine supply chain costs, and $1.33 (s.d. $0.82) when including immunization service delivery costs. In Tanzania, these costs were $0.67 (s.d. $0.35) and $2.82 (s.d. $1.64), respectively. Both countries experienced vaccine stockouts in 2012, bacillus Calmette-Guérin vaccine being more likely to be stocked out in Kenya, and oral poliovirus vaccine in Tanzania. When stockouts happened, they usually lasted for at least one month. Tanzania made investments in 2011 in preparation for planned vaccine introductions, and their supply chain cost per dose is expected to decline with the new vaccine introductions. Immunization service delivery costs are a significant portion of the total costs at the SDPs. Copyright © 2015 Elsevier Ltd. All

Incremental costs of introducing jet injection technology for delivery of routine childhood vaccinations: comparative analysis from Brazil, India, and South Africa.

PubMed

Griffiths, Ulla K; Santos, Andreia C; Nundy, Neeti; Jacoby, Erica; Matthias, Dipika

2011-01-29

Disposable-syringe jet injectors (DSJIs) have the potential to deliver vaccines safely and affordably to millions of children around the world. We estimated the incremental costs of transitioning from needles and syringes to delivering childhood vaccines with DSJIs in Brazil, India, and South Africa. Two scenarios were assessed: (1) DSJI delivery of all vaccines at current dose and depth; (2) a change to intradermal (ID) delivery with DSJIs for hepatitis B and yellow fever vaccines, while the other vaccines are delivered by DSJIs at current dose and depth. The main advantage of ID delivery is that only a small fraction of the standard dose may be needed to obtain an immune response similar to that of subcutaneous or intramuscular injection. Cost categories included were vaccines, injection equipment, waste management, and vaccine transport. Some delivery cost items, such as training and personnel were excluded as were treatment cost savings caused by a reduction in diseases transmitted due to unsafe injections. In the standard dose and depth scenario, the incremental costs of introducing DSJIs per fully vaccinated child amount to US$ 0.57 in Brazil, US$ 0.65 in India and US$ 1.24 in South Africa. In the ID scenario, there are cost savings of US$ 0.11 per child in Brazil, and added costs of US$ 0.45 and US$ 0.76 per child in India and South Africa, respectively. The most important incremental cost item is jet injector disposable syringes. The incremental costs should be evaluated against other vaccine delivery technologies that can deliver the same benefits to patients, health care workers, and the community. DSJIs deserve consideration by global and national decision-makers as a means to expand access to ID delivery and to enhance safety at marginal additional cost. Copyright © 2010 Elsevier Ltd. All rights reserved.

Strategies to advance vaccine technologies for resource-poor settings.

PubMed

Kristensen, Debra; Chen, Dexiang

2013-04-18

New vaccine platform and delivery technologies that can have significant positive impacts on the effectiveness, acceptability, and safety of immunizations in developing countries are increasingly available. Although donor support for vaccine technology development is strong, the uptake of proven technologies by the vaccine industry and demand for them by purchasers continues to lag. This article explains the challenges and opportunities associated with accelerating the availability of innovative and beneficial vaccine technologies to meet critical needs in resource-poor settings over the next decade. Progress will require increased dialog between the public and private sectors around vaccine product attributes; establishment of specifications for vaccines that mirror programmatic needs; stronger encouragement of vaccine developers to consider novel technologies early in the product development process; broader facilitation of research and access to technologies through the formation of centers of excellence; the basing of vaccine purchase decisions on immunization systems costs rather than price per dose alone; possible subsidization of early technology adoption costs for vaccine producers that take on the risks of new technologies of importance to the public sector; and the provision of data to purchasers, better enabling them to make informed decisions that take into account the value of specific product attributes. Copyright © 2012 Elsevier Ltd. All rights reserved.

A paradigm for peptide vaccine delivery using viral epitopes encapsulated in degradable polymer hydrogel capsules.

PubMed

Chong, Siow-Feng; Sexton, Amy; De Rose, Robert; Kent, Stephen J; Zelikin, Alexander N; Caruso, Frank

2009-10-01

We report on the use of degradable polymer capsules as carriers for the delivery of oligopeptide antigens to professional antigen presenting cells (APCs). To achieve encapsulation, oligopeptide sequences were covalently linked to a negatively charged carrier polymer via biodegradable linkages and the resulting conjugate was then adsorbed onto amine-functionalized silica particles. These peptide-coated particles were then used as templates for the layer-by-layer (LbL) deposition of thiolated poly(methacrylic acid) (PMA(SH)) and poly(vinylpyrrolidone) (PVPON) multilayers. Removal of the silica core and disruption of the hydrogen bonding between PMA(SH) and PVPON by altering the solution pH yielded disulfide-stabilized PMA capsules that retain the encapsulated cargo in an oxidative environment. In the presence of a natural reducing agent, glutathione, cleavage of the disulfide bonds causes release of the peptide from the capsules. The developed strategy provides control over peptide loading into polymer capsules and yields colloidally stable micron- and submicron-sized carriers with uniform size and peptide loading. The conjugation and encapsulation procedures were proven to be non-degrading to the peptide vaccines. The peptide-loaded capsules were successfully used to deliver their cargo to APCs and activate CD8 T lymphocytes in a non-human primate model of SIV infection ex vivo. The reported approach represents a novel paradigm in the delivery of peptide vaccines and other therapeutic agents.

School-based vaccination programmes: a systematic review of the evidence on organisation and delivery in high income countries.

PubMed

Perman, Sarah; Turner, Simon; Ramsay, Angus I G; Baim-Lance, Abigail; Utley, Martin; Fulop, Naomi J

2017-03-14

Many countries have recently expanded their childhood immunisation programmes. Schools are an increasingly attractive setting for delivery of these new immunisations because of their ability to reach large numbers of children in a short period of time. However, there are organisational challenges to delivery of large-scale vaccination programmes in schools. Understanding the facilitators and barriers is important for improving the delivery of future school-based vaccination programmes. We undertook a systematic review of evidence on school-based vaccination programmes in order to understand the influence of organisational factors on the delivery of programmes. Our eligibility criteria were studies that (1) focused on childhood or adolescent vaccination programmes delivered in schools; (2) considered organisational factors that influenced the preparation or delivery of programmes; (3) were conducted in a developed or high-income country; and (4) had been peer reviewed. We searched for articles published in English between 2000 and 2015 using MEDLINE and HMIC electronic databases. Additional studies were identified by searching the Cochrane Library and bibliographies. We extracted data from the studies, assessed quality and the risk of bias, and categorised findings using a thematic framework of eight organisational factors. We found that most of the recent published literature is from the United States and is concerned with the delivery of pandemic or seasonal flu vaccination programmes at a regional (state) or local level. We found that the literature is largely descriptive and not informed by the use of theory. Despite this, we identified common factors that influence the implementation of programmes. These factors included programme leadership and governance, organisational models and institutional relationships, workforce capacity and roles particularly concerning the school nurse, communication with parents and students, including methods for obtaining consent

Human papillomavirus (HPV) vaccine coverage achievements in low and middle-income countries 2007-2016.

PubMed

Gallagher, Katherine E; Howard, Natasha; Kabakama, Severin; Mounier-Jack, Sandra; Burchett, Helen E D; LaMontagne, D Scott; Watson-Jones, Deborah

2017-12-01

Since 2007, HPV vaccine has been available to low and middle income countries (LAMIC) for small-scale 'demonstration projects', or national programmes. We analysed coverage achieved in HPV vaccine demonstration projects and national programmes that had completed at least 6 months of implementation between January 2007-2016. A mapping exercise identified 45 LAMICs with HPV vaccine delivery experience. Estimates of coverage and factors influencing coverage were obtained from 56 key informant interviews, a systematic published literature search of 5 databases that identified 61 relevant full texts and 188 solicited unpublished documents, including coverage surveys. Coverage achievements were analysed descriptively against country or project/programme characteristics. Heterogeneity in data, funder requirements, and project/programme design precluded multivariate analysis. Estimates of uptake, schedule completion rates and/or final dose coverage were available from 41 of 45 LAMICs included in the study. Only 17 estimates from 13 countries were from coverage surveys, most were administrative data. Final dose coverage estimates were all over 50% with most between 70% and 90%, and showed no trend over time. The majority of delivery strategies included schools as a vaccination venue. In countries with school enrolment rates below 90%, inclusion of strategies to reach out-of-school girls contributed to obtaining high coverage compared to school-only strategies. There was no correlation between final dose coverage and estimated recurrent financial costs of delivery from cost analyses. Coverage achieved during joint delivery of HPV vaccine combined with another intervention was variable with little/no evaluation of the correlates of success. This is the most comprehensive descriptive analysis of HPV vaccine coverage in LAMICs to date. It is possible to deliver HPV vaccine with excellent coverage in LAMICs. Further good quality data are needed from health facility based

Vaccine Development for Zika Virus-Timelines and Strategies.

PubMed

Durbin, Anna P

2016-09-01

Zika virus is a mosquito-borne Flavivirus that spread rapidly through South and Central America in 2015 to 2016. Microcephaly has been causally associated with Zika virus infection during pregnancy and the World Health Organization declared Zika virus as a Public Health Emergency of International Concern. To address this crisis, many groups have expressed their commitment to developing a Zika virus vaccine. Different strategies for Zika virus vaccine development are being considered including recombinant live attenuated vaccines, purified inactivated vaccines (PIVs), DNA vaccines, and viral vectored vaccines. Important to Zika virus vaccine development will be the target group chosen for vaccination and which end point(s) is chosen for efficacy determination. The first clinical trials of Zika virus vaccine candidates will begin in Q3/4 2016 but the pathway to licensure for a Zika virus vaccine is expected to take several years. Efforts are ongoing to accelerate Zika virus vaccine development and evaluation with the ultimate goal of reducing time to licensure. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

A cost comparison of introducing and delivering pneumococcal, rotavirus and human papillomavirus vaccines in Rwanda.

PubMed

Ngabo, Fidèle; Levin, Ann; Wang, Susan A; Gatera, Maurice; Rugambwa, Celse; Kayonga, Celestin; Donnen, Philippe; Lepage, Philippe; Hutubessy, Raymond

2015-12-16

Detailed cost evaluations of delivery of new vaccines such as pneumococcal conjugate, human papillomavirus (HPV), and rotavirus vaccines in low and middle-income countries are scarce. This paper differs from others by comparing the costs of introducing multiple vaccines in a single country and then assessing the financial and economic impact at the time and implications for the future. The objective of the analysis was to understand the introduction and delivery cost per dose or per child of the three new vaccines in Rwanda to inform domestic and external financial resource mobilization. Start-up, recurrent, and capital costs from a government perspective were collected in 2012. Since pneumococcal conjugate and HPV vaccines had already been introduced, cost data for those vaccines were collected retrospectively while prospective (projected) costing was done for rotavirus vaccine. The financial unit cost per fully immunized child (or girl for HPV vaccine) of delivering 3 doses of each vaccine (without costs related to vaccine procurement) was $0.37 for rotavirus (RotaTeq(®)) vaccine, $0.54 for pneumococcal (Prevnar(®)) vaccine in pre-filled syringes, and $10.23 for HPV (Gardasil (®)) vaccine. The financial delivery costs of Prevnar(®) and RotaTeq(®) were similar since both were delivered using existing health system infrastructure to deliver infant vaccines at health centers. The total financial cost of delivering Gardasil(®) was higher than those of the two infant vaccines due to greater resource requirements associated with creating a new vaccine delivery system in for a new target population of 12-year-old girls who have not previously been served by the existing routine infant immunization program. The analysis indicates that service delivery strategies have an important influence on costs of introducing new vaccines and costs per girl reached with HPV vaccine are higher than the other two vaccines because of its delivery strategy. Documented information

Percutaneous Vaccination as an Effective Method of Delivery of MVA and MVA-Vectored Vaccines.

PubMed

Meseda, Clement A; Atukorale, Vajini; Kuhn, Jordan; Schmeisser, Falko; Weir, Jerry P

2016-01-01

The robustness of immune responses to an antigen could be dictated by the route of vaccine inoculation. Traditional smallpox vaccines, essentially vaccinia virus strains, that were used in the eradication of smallpox were administered by percutaneous inoculation (skin scarification). The modified vaccinia virus Ankara is licensed as a smallpox vaccine in Europe and Canada and currently undergoing clinical development in the United States. MVA is also being investigated as a vector for the delivery of heterologous genes for prophylactic or therapeutic immunization. Since MVA is replication-deficient, MVA and MVA-vectored vaccines are often inoculated through the intramuscular, intradermal or subcutaneous routes. Vaccine inoculation via the intramuscular, intradermal or subcutaneous routes requires the use of injection needles, and an estimated 10 to 20% of the population of the United States has needle phobia. Following an observation in our laboratory that a replication-deficient recombinant vaccinia virus derived from the New York City Board of Health strain elicited protective immune responses in a mouse model upon inoculation by tail scarification, we investigated whether MVA and MVA recombinants can elicit protective responses following percutaneous administration in mouse models. Our data suggest that MVA administered by percutaneous inoculation, elicited vaccinia-specific antibody responses, and protected mice from lethal vaccinia virus challenge, at levels comparable to or better than subcutaneous or intramuscular inoculation. High titers of specific neutralizing antibodies were elicited in mice inoculated with a recombinant MVA expressing the herpes simplex type 2 glycoprotein D after scarification. Similarly, a recombinant MVA expressing the hemagglutinin of attenuated influenza virus rgA/Viet Nam/1203/2004 (H5N1) elicited protective immune responses when administered at low doses by scarification. Taken together, our data suggest that MVA and MVA

Vaccine delivery management.

PubMed

Cheyne, J

1989-01-01

During the typical 12- to 18-month voyage of a vaccine from manufacturer to immunization site, many situations arise in which the cold chain may be interrupted. Extensive efforts have been made in the 1980s to ensure an uninterrupted cold chain through the use of improved equipment and better training of personnel. One important advance is the vaccine cold-chain monitor, which identifies weak spots in the cold chain and prevents the use of heat-damaged vaccine. Further improvements will require efforts by the recipient countries (e.g., better use of the private sector for transport and equipment management), by donor agencies (e.g., greater consideration of the operational and maintenance costs of the equipment selected and resolution of fuel shortages), and by industry (e.g., more appropriate packaging and pricing of vaccine, extension of the expiration period, and increased heat stability.

In vivo investigation of twin-screw extruded lipid implants for vaccine delivery.

PubMed

Even, Marie-Paule; Young, Katie; Winter, Gerhard; Hook, Sarah; Engert, Julia

2014-07-01

Sustained release systems have become the focus of attention in vaccine delivery as they may reduce or prevent the need for repeated dosing. In this work, lipid implants were prepared by twin-screw extrusion and investigated as vaccine delivery systems in vivo. The lipid implants consisted of cholesterol, soybean lecithin, and Dynasan 114. Ovalbumin (OVA) was employed as a model antigen and Quil-A (QA) as an adjuvant. In addition, OVA and QA loaded liposomes were prepared by the lipid-film hydration method, freeze-dried and then added to the lipid matrix prior to extrusion. Implants were administered subcutaneously and the kinetics of antigen release as well as the overall immune response stimulated were analysed by measuring CD4(+) and CD8(+) T cell proliferation, OVA-specific IgG production as well as cytokine (IFN-γ and IL4) secretion. Vaccine release from the implants was completed by 14 days. Inclusion of adjuvant into the implants was required for the generation of cellular and humoral immune responses. Inclusion of liposomes into the implant did not enhance the resulting immune responses generated. Copyright © 2014 Elsevier B.V. All rights reserved.

Costs of Introducing and Delivering HPV Vaccines in Low and Lower Middle Income Countries: Inputs for GAVI Policy on Introduction Grant Support to Countries

PubMed Central

Levin, Ann; Wang, Susan A.; Levin, Carol; Tsu, Vivien; Hutubessy, Raymond

2014-01-01

Background In November 2011, the GAVI Alliance made the decision to add HPV vaccine as one of the new vaccines for which countries eligible for its funding (less than $1520 per capita income) could apply to receive support for national HPV vaccination, provided they could demonstrate the ability to deliver HPV vaccines. This paper describes the data and analysis shared with GAVI policymakers for this decision regarding GAVI HPV vaccine support. The paper reviews why strategies and costs for HPV vaccine delivery are different from other vaccines and what is known about the cost components from available data that originated primarily from HPV vaccine delivery costing studies in low and middle income-countries. Methods Financial costs of HPV vaccine delivery were compared across three sources of data: 1) vaccine delivery costing of pilot projects in five low and lower-middle income countries; 2) cost estimates of national HPV vaccination in two low income countries; and 3) actual expenditure data from national HPV vaccine introduction in a low income country. Both costs of resources required to introduce the vaccine (or initial one-time investment, such as cold chain equipment purchases) and recurrent (ongoing costs that repeat every year) costs, such as transport and health personnel time, were analyzed. The cost per dose, cost per fully immunized girl (FIG) and cost per eligible girl were compared across studies. Results Costs varied among pilot projects and estimates of national programs due to differences in scale and service delivery strategy. The average introduction costs per fully immunized girl ranged from $1.49 to $18.94 while recurrent costs per girl ranged from $1.00 to $15.69, with both types of costs varying by delivery strategy and country. Evaluating delivery costs along programme characteristics as well as country characteristics (population density, income/cost level, existing service delivery infrastructure) are likely the most informative and

Costs of introducing and delivering HPV vaccines in low and lower middle income countries: inputs for GAVI policy on introduction grant support to countries.

PubMed

Levin, Ann; Wang, Susan A; Levin, Carol; Tsu, Vivien; Hutubessy, Raymond

2014-01-01

In November 2011, the GAVI Alliance made the decision to add HPV vaccine as one of the new vaccines for which countries eligible for its funding (less than $1520 per capita income) could apply to receive support for national HPV vaccination, provided they could demonstrate the ability to deliver HPV vaccines. This paper describes the data and analysis shared with GAVI policymakers for this decision regarding GAVI HPV vaccine support. The paper reviews why strategies and costs for HPV vaccine delivery are different from other vaccines and what is known about the cost components from available data that originated primarily from HPV vaccine delivery costing studies in low and middle income-countries. Financial costs of HPV vaccine delivery were compared across three sources of data: 1) vaccine delivery costing of pilot projects in five low and lower-middle income countries; 2) cost estimates of national HPV vaccination in two low income countries; and 3) actual expenditure data from national HPV vaccine introduction in a low income country. Both costs of resources required to introduce the vaccine (or initial one-time investment, such as cold chain equipment purchases) and recurrent (ongoing costs that repeat every year) costs, such as transport and health personnel time, were analyzed. The cost per dose, cost per fully immunized girl (FIG) and cost per eligible girl were compared across studies. Costs varied among pilot projects and estimates of national programs due to differences in scale and service delivery strategy. The average introduction costs per fully immunized girl ranged from $1.49 to $18.94 while recurrent costs per girl ranged from $1.00 to $15.69, with both types of costs varying by delivery strategy and country. Evaluating delivery costs along programme characteristics as well as country characteristics (population density, income/cost level, existing service delivery infrastructure) are likely the most informative and useful for anticipating costs

Immunomodulatory properties of vitamins, flavonoids and plant oils and their potential as vaccine adjuvants and delivery systems.

PubMed

Vajdy, Michael

2011-11-01

During the past century, vaccinologists have attempted to mimic pathogens in their immune-enhancing capacity. This led to the development of life-saving vaccines based on live attenuated viruses, bacteria and toxoids. Hence, intense research in vaccine adjuvant discovery has focused on toll like receptors, mutant toxins and viral and bacterial vectors. Nutritive components such as vitamins and select polyphenols also possess immunomodulating properties without the potential toxic and adverse side effects of agents that mimic danger signals. This review pertains to immunomodulatory properties of nutritive components, that is vitamins A, C, D, E, flavonoids and plant oils, as potential vaccine adjuvants and delivery systems, covering Pubmed publication searches from 1980 through 2011. This relatively unexplored field of the potential of nutritive components as vaccine adjuvants holds great promise to promote the development of effective and above all safe vaccines. Hence the future focus should be placed on enhancing their efficacy, mainly through novel approaches in designing structural derivatives, formulations, delivery systems and routes of administration. As safety has been the major issue in development of novel vaccines, this new approach will probably result in new discoveries in designing safe and effective vaccines.

Estimating the cost of cholera-vaccine delivery from the societal point of view: A case of introduction of cholera vaccine in Bangladesh.

PubMed

Sarker, Abdur Razzaque; Islam, Ziaul; Khan, Iqbal Ansary; Saha, Amit; Chowdhury, Fahima; Khan, Ashraful Islam; Cravioto, Alejandro; Clemens, John David; Qadri, Firdausi; Khan, Jahangir A M

2015-09-11

Cholera is a major global public health problem that causes both epidemic and endemic disease. The World Health Organization recommends oral cholera vaccines as a public health tool in addition to traditional prevention practices and treatments in both epidemic and endemic settings. In many developing countries like Bangladesh, the major issue concerns the affordability of this vaccine. In February 2011, a feasibility study entitled, "Introduction of Cholera Vaccine in Bangladesh (ICVB)", was conducted for a vaccination campaign using inactivated whole-cell cholera vaccine (Shanchol) in a high risk area of Mirpur, Dhaka. Empirical data obtained from this trial was used to determine the vaccination cost for a fully immunized person from the societal perspective. A total of 123,661 people were fully vaccinated receiving two doses of the vaccine, while 18,178 people received one dose of the same vaccine. The total cost for vaccine delivery was US$ 492,238 giving a total vaccination cost per fully-vaccinated individual of US$ 3.98. The purchase cost of the vaccine accounted for 58% of the overall cost of vaccination. Attempts to reduce the per-dose cost of the vaccine are likely to have a large impact on the cost of similar vaccination campaigns in the future. Copyright © 2015 Elsevier Ltd. All rights reserved.

Current state and challenges in developing oral vaccines.

PubMed

Vela Ramirez, Julia E; Sharpe, Lindsey A; Peppas, Nicholas A

2017-05-15

While vaccination remains the most cost effective strategy for disease prevention, communicable diseases persist as the second leading cause of death worldwide. There is a need to design safe, novel vaccine delivery methods to protect against unaddressed and emerging diseases. Development of vaccines administered orally is preferable to traditional injection-based formulations for numerous reasons including improved safety and compliance, and easier manufacturing and administration. Additionally, the oral route enables stimulation of humoral and cellular immune responses at both systemic and mucosal sites to establish broader and long-lasting protection. However, oral delivery is challenging, requiring formulations to overcome the harsh gastrointestinal (GI) environment and avoid tolerance induction to achieve effective protection. Here we address the rationale for oral vaccines, including key biological and physicochemical considerations for next-generation oral vaccine design. Copyright © 2017 Elsevier B.V. All rights reserved.

Factors affecting the implementation of childhood vaccination communication strategies in Nigeria: a qualitative study.

PubMed

Oku, Afiong; Oyo-Ita, Angela; Glenton, Claire; Fretheim, Atle; Eteng, Glory; Ames, Heather; Muloliwa, Artur; Kaufman, Jessica; Hill, Sophie; Cliff, Julie; Cartier, Yuri; Bosch-Capblanch, Xavier; Rada, Gabriel; Lewin, Simon

2017-02-15

The role of health communication in vaccination programmes cannot be overemphasized: it has contributed significantly to creating and sustaining demand for vaccination services and improving vaccination coverage. In Nigeria, numerous communication approaches have been deployed but these interventions are not without challenges. We therefore aimed to explore factors affecting the delivery of vaccination communication in Nigeria. We used a qualitative approach and conducted the study in two states: Bauchi and Cross River States in northern and southern Nigeria respectively. We identified factors affecting the implementation of communication interventions through interviews with relevant stakeholders involved in vaccination communication in the health services. We also reviewed relevant documents. Data generated were transcribed verbatim and analysed using thematic analysis. We used the SURE framework to organise the identified factors (barriers and facilitators) affecting vaccination communication delivery. We then grouped these into health systems and community level factors. Some of the commonly reported health system barriers amongst stakeholders interviewed included: funding constraints, human resource factors (health worker shortages, training deficiencies, poor attitude of health workers and vaccination teams), inadequate infrastructure and equipment and weak political will. Community level factors included the attitudes of community stakeholders and of parents and caregivers. We also identified factors that appeared to facilitate communication activities. These included political support, engagement of traditional and religious institutions and the use of organised communication committees. Communication activities are a crucial element of immunization programmes. It is therefore important for policy makers and programme managers to understand the barriers and facilitators affecting the delivery of vaccination communication so as to be able to implement

M cell-targeting strategy facilitates mucosal immune response and enhances protection against CVB3-induced viral myocarditis elicited by chitosan-DNA vaccine.

PubMed

Ye, Ting; Yue, Yan; Fan, Xiangmei; Dong, Chunsheng; Xu, Wei; Xiong, Sidong

2014-07-31

Efficient delivery of antigen to mucosal associated lymphoid tissue is a first and critical step for successful induction of mucosal immunity by vaccines. Considering its potential transcytotic capability, M cell has become a more and more attractive target for mucosal vaccines. In this research, we designed an M cell-targeting strategy by which mucosal delivery system chitosan (CS) was endowed with M cell-targeting ability via conjugating with a CPE30 peptide, C terminal 30 amino acids of clostridium perfringens enterotoxin (CPE), and then evaluated its immune-enhancing ability in the context of coxsackievirus B3 (CVB3)-specific mucosal vaccine consisting of CS and a plasmid encoding CVB3 predominant antigen VP1. It had shown that similar to CS-pVP1, M cell-targeting CPE30-CS-pVP1 vaccine appeared a uniform spherical shape with about 300 nm diameter and +22 mV zeta potential, and could efficiently protect DNA from DNase I digestion. Mice were orally immunized with 4 doses of CPE30-CS-pVP1 containing 50 μg pVP1 at 2-week intervals and challenged with CVB3 4 weeks after the last immunization. Compared with CS-pVP1 vaccine, CPE30-CS-pVP1 vaccine had no obvious impact on CVB3-specific serum IgG level and splenic T cell immune responses, but significantly increased specific fecal SIgA level and augmented mucosal T cell immune responses. Consequently, much milder myocarditis and lower viral load were witnessed in CPE30-CS-pVP1 immunized group. The enhanced immunogenicity and immunoprotection were associated with the M cell-targeting ability of CPE30-CS-pVP1 which improved its mucosal uptake and transcytosis. Our findings indicated that CPE30-CS-pVP1 may represent a novel prophylactic vaccine against CVB3-induced myocarditis, and this M cell-targeting strategy indeed could be applied as a promising and universal platform for mucosal vaccine development. Copyright © 2014 Elsevier Ltd. All rights reserved.

Impact of Coverage-Dependent Marginal Costs on Optimal HPV Vaccination Strategies

PubMed Central

Ryser, Marc D.; McGoff, Kevin; Herzog, David P.; Sivakoff, David J.; Myers, Evan R.

2015-01-01

The effectiveness of vaccinating males against the human papillomavirus (HPV) remains a controversial subject. Many existing studies conclude that increasing female coverage is more effective than diverting resources into male vaccination. Recently, several empirical studies on HPV immunization have been published, providing evidence of the fact that marginal vaccination costs increase with coverage. In this study, we use a stochastic agent-based modeling framework to revisit the male vaccination debate in light of these new findings. Within this framework, we assess the impact of coverage-dependent marginal costs of vaccine distribution on optimal immunization strategies against HPV. Focusing on the two scenarios of ongoing and new vaccination programs, we analyze different resource allocation policies and their effects on overall disease burden. Our results suggest that if the costs associated with vaccinating males are relatively close to those associated with vaccinating females, then coverage-dependent, increasing marginal costs may favor vaccination strategies that entail immunization of both genders. In particular, this study emphasizes the necessity for further empirical research on the nature of coverage-dependent vaccination costs. PMID:25979280

Micro/nanoparticle adjuvants for antileishmanial vaccines: present and future trends.

PubMed

Badiee, Ali; Heravi Shargh, Vahid; Khamesipour, Ali; Jaafari, Mahmoud Reza

2013-01-21

Leishmania infection continues to have a major impact on public health inducing significant morbidity and mortality mostly in the poorest populations. Drug resistance, toxicity and side effects associated with expensive chemotherapeutic treatments and difficult reservoir control emphasize the need for a safe and effective vaccine which is not available yet. Although, Leishmanization (LZ) was shown to be effective against cutaneous leishmaniasis, standardization and safety are the main problems of LZ. First generation killed parasites demonstrated limited efficacy in phase 3 trials and moreover well defined molecules have not reached to phase 3 yet. Limited efficacy in vaccines against leishmaniasis is partly due to lack of an appropriate adjuvant. Hence, the use of particulate delivery systems as carriers for antigen and/or immunostimulatory adjuvants for effective delivery to the antigen-presenting cells (APCs) is a valuable strategy to enhance vaccine efficacies. Particle-based delivery systems such as emulsions, liposomes, virosomes, and polymeric microspheres have the potential for successfully delivering antigens, which can then be further improved via incorporation of additional antigenic or immustimulatory adjuvant components in or onto the particle carrier system. In this review, we have attempted to provide a list of particulate vaccine delivery systems involved in the production of candidate leishmaniasis vaccines and introduced some potentially useful vaccine delivery systems for leishmaniasis in future experiments. In conclusion, combination vaccines (adjuvant systems) composed of candidate antigens and more importantly well-developed particulate delivery systems, such as lipid-based particles containing immunostimulatory adjuvants, have a chance to succeed as antileishmanial vaccines. Copyright © 2012 Elsevier Ltd. All rights reserved.

An Overview on the Field of Micro- and Nanotechnologies for Synthetic Peptide-Based Vaccines

PubMed Central

Salvador, Aiala; Igartua, Manoli; Hernández, Rosa Maria; Pedraz, José Luis

2011-01-01

The development of synthetic peptide-based vaccines has many advantages in comparison with vaccines based on live attenuated organisms, inactivated or killed organism, or toxins. Peptide-based vaccines cannot revert to a virulent form, allow a better conservation, and are produced more easily and safely. However, they generate a weaker immune response than other vaccines, and the inclusion of adjuvants and/or the use of vaccine delivery systems is almost always needed. Among vaccine delivery systems, micro- and nanoparticulated ones are attractive, because their particulate nature can increase cross-presentation of the peptide. In addition, they can be passively or actively targeted to antigen presenting cells. Furthermore, particulate adjuvants are able to directly activate innate immune system in vivo. Here, we summarize micro- and nanoparticulated vaccine delivery systems used in the field of synthetic peptide-based vaccines as well as strategies to increase their immunogenicity. PMID:21773041

Parental regret regarding children's vaccines-The correlation between anticipated regret, altruism, coping strategies and attitudes toward vaccines.

PubMed

Hamama-Raz, Yaira; Ginossar-David, Eyal; Ben-Ezra, Menachem

2016-01-01

Parental hesitancy for recommended childhood vaccines is a growing public health concern influenced by various factors. This study aimed to explore regret regarding parental decisions to vaccinate their children via possible correlations between anticipated regret, altruism, coping strategies, and parents' attitudes toward the vaccination of their children. The study was conducted during 2014 in Israel. Data were collected via snowballing methodology (i.e., Internet forums, Facebook and e- mails). 314 parents of children ages 0-6 years participated in the study. Questionnaires were distributed and completed on-line including attitudes toward vaccines, altruism, coping strategies, regret and anticipated regret. Pearson analysis revealed a moderate negative association between attitudes toward vaccinations and regret. In addition, weak but significant positive associations emerged between anticipated regret and regret as well as between gender and regret. Performing hierarchical regression analysis revealed contribution of 35.9 % to the explained variance of regret suggesting that coping strategy of instrumental support, attitudes toward vaccinations and anticipated regret are linked significantly to regret. Parental attitudes toward vaccines and anticipated regret have a salient role when deciding whether or not to vaccinate children and contribute to the prediction of regret regarding vaccination. In order to increase parental consent to vaccination of their children, it is important to minimize possible regret through the strength of the recommendation and/or knowledge base about risk/benefit (perceived, heuristic) of vaccines that might influence parental attitudes and lessen their anticipated regret. N/A. This is not a clinical trial and thus does not require registration. Ethics approval was received from Ariel University School of Social Work Ethics committee (18/02/14). This was an attitude survey. The Ariel University School of Social Work Ethics committee

Potential of polymeric particles as future vaccine delivery systems/adjuvants for parenteral and non-parenteral immunization against tuberculosis: A systematic review.

PubMed

Khademi, Farzad; Derakhshan, Mohammad; Yousefi-Avarvand, Arshid; Tafaghodi, Mohsen

2018-02-01

Production of effective tuberculosis (TB) vaccine is necessity. However, the development of new subunit vaccines is faced with concerns about their weak immunogenicity. To overcome such problems, polymers-based vaccine delivery systems have been proposed to be used via various routes. The purpose of this study was to determine the potential of polymeric particles as future vaccine delivery systems/adjuvants for parenteral and non-parenteral immunization against TB. PubMed, Scopus, Science-Direct, and the ISI web of knowledge databases were searched for related keywords. A total of 420 articles, written up to June 25, 2016, were collected on the potential of polymeric particles as TB vaccine delivery systems after parenteral and non-parenteral immunization. Thirty-one relevant articles were selected by applying inclusion and exclusion criteria. It was shown that the immunogenicity of TB vaccines had been improved by using biodegradable and non-biodegradable synthetic polymers as well as natural polymers and they are better able to enhance the humoral and cellular immune responses, compared to TB vaccines alone. The present study revealed that various polymeric particles, after M. tuberculosis challenge in animal models, provide long-lasting protection against TB. PLGA (poly (lactide-co-glycolide)) and chitosan polymers were widely used as TB vaccine delivery systems/adjuvants. It seems that PLGA and chitosan polymers are well-suited particles for the parenteral and non-parenteral administration of TB vaccines, respectively. Non-biodegradable synthetic polymers in comparison with biodegradable synthetic and natural polymers have been used less frequently. Therefore, further study on this category of polymers is required.

Oral Vaccination with a DNA Vaccine Encoding Capsid Protein of Duck Tembusu Virus Induces Protection Immunity

PubMed Central

Shen, Haoyue; Jia, Renyong; Wang, Mingshu; Chen, Shun; Zhu, Dekang; Liu, Mafeng; Zhao, Xinxin; Yang, Qiao; Wu, Ying; Liu, Yunya; Zhang, Ling; Yin, Zhongqiong; Jing, Bo

2018-01-01

The emergence of duck tembusu virus (DTMUV), a new member of the Flavivirus genus, has caused great economical loss in the poultry industry in China. Since the outbreak and spread of DTMUV is hard to control in a clinical setting, an efficient and low-cost oral delivery DNA vaccine SL7207 (pVAX1-C) based on the capsid protein of DTMUV was developed and evaluated in this study. The antigen capsid protein was expressed from the DNA vaccine SL7207 (pVAX1-C), both in vitro and in vivo. The humoral and cellular immune responses in vivo were observed after oral immunization with the SL7207 (pVAX1-C) DNA vaccine. High titers of the specific antibody against the capsid protein and the neutralizing antibody against the DTMUV virus were both detected after inoculation. The ducks were efficiently protected from lethal DTMUV exposure by the SL7207 (pVAX1-C) vaccine in this experiment. Taken together, we demonstrated that the capsid protein of DTMUV possesses a strong immunogenicity against the DTMUV infection. Moreover, an oral delivery of the DNA vaccine SL7207 (pVAX1-C) utilizing Salmonella SL7207 was an efficient way to protect the ducks against DTMUV infection and provides an economic and fast vaccine delivery strategy for a large scale clinical use. PMID:29642401

Development of an epitope-based HIV-1 vaccine strategy from HIV-1 lipopeptide to dendritic-based vaccines.

PubMed

Surenaud, Mathieu; Lacabaratz, Christine; Zurawski, Gérard; Lévy, Yves; Lelièvre, Jean-Daniel

2017-10-01

Development of a safe, effective and globally affordable Human Immunodeficiency Virus strain 1 (HIV-1) vaccine offers the best hope for future control of the HIV-1 pandemic. However, with the exception of the recent RV144 trial, which elicited a modest level of protection against infection, no vaccine candidate has shown efficacy in preventing HIV-1 infection or in controlling virus replication in humans. There is also a great need for a successful immunotherapeutic vaccine since combination antiretroviral therapy (cART) does not eliminate the reservoir of HIV-infected cells. But to date, no vaccine candidate has proven to significantly alter the natural history of an individual with HIV-1 infection. Areas covered: For over 25 years, the ANRS (France Recherche Nord&Sud Sida-HIV hépatites) has been committed to an original program combining basic science and clinical research developing an epitope-based vaccine strategy to induce a multiepitopic cellular response against HIV-1. This review describes the evolution of concepts, based on strategies using HIV-1 lipopeptides towards the use of dendritic cell (DC) manipulation. Expert commentary: Understanding the crucial role of DCs in immune responses allowed moving from the non-specific administration of HIV-1 sequences with lipopeptides to DC-based vaccines. These DC-targeting strategies should improve HIV-1 vaccine efficacy.

Intranasal cold-adapted influenza virus vaccine combined with inactivated influenza virus vaccines: an extra boost for the elderly?

PubMed

Targonski, Paul V; Poland, Gregory A

2004-01-01

Although influenza vaccine delivery strategies have improved coverage rates to unprecedented levels nationally among persons aged 65 years and older, influenza remains one of the greatest vaccine-preventable threats to public health among elderly in the US. A new, intranasal live attenuated influenza vaccine (LAIV) was recently approved by the US FDA for use in persons aged 5-49 years, which excludes the elderly population. Limitations of immune response to inactivated influenza vaccine (IAIV) and effectiveness of current influenza vaccination strategies among the elderly suggest that a combined approach using LAIV and/or the IAIV in various permutations might benefit this group. We explore characteristics of the LAIV, data regarding its utility in protecting against influenza in the elderly, and challenges and opportunities regarding potential combined inactivated/live attenuated vaccination strategies for the elderly. Although LAIV appears to hold promise either alone or in combination with IAIV, large well conducted randomised trials are necessary to define further the role of LAIV in preventing influenza morbidity and mortality among the elderly. We also suggest that innovative vaccine coverage strategies designed to optimise prevention and control of influenza and minimise viral transmission in the community must accompany, in parallel, the acquisition of clinical trials data to best combat morbidity and mortality from influenza.

Comparison of vaccine efficacy for different antigen delivery systems for infectious pancreatic necrosis virus vaccines in Atlantic salmon (Salmo salar L.) in a cohabitation challenge model.

PubMed

Munang'andu, Hetron M; Fredriksen, Børge N; Mutoloki, Stephen; Brudeseth, Bjørn; Kuo, Tsun-Yung; Marjara, Inderjit S; Dalmo, Roy A; Evensen, Øystein

2012-06-08

Two strains of IPNV made by reverse genetics on the Norwegian Sp strain NVI-015 (GenBank AY379740) backbone encoding the virulent (T(217)A(221)) and avirulent (P(217)T(221)) motifs were used to prepare inactivated whole virus (IWV), nanoparticle vaccines with whole virus, Escherichia coli subunit encoding truncated VP2-TA and VP2-PT, VP2-TA and VP2-PT fusion antigens with putative translocating domains of Pseudomonas aeruginosa exotoxin, and plasmid DNA encoding segment A of the TA strain. Post challenge survival percentages (PCSP) showed that IWV vaccines conferred highest protection (PCSP=42-53) while nanoparticle, sub-unit recombinant and DNA vaccines fell short of the IWV vaccines in Atlantic salmon (Salmo salar L.) postsmolts challenged with the highly virulent Sp strain NVI-015 (TA strain) of IPNV after 560 degree days post vaccination. Antibody levels induced by these vaccines did not show antigenic differences between the virulent and avirulent motifs for vaccines made with the same antigen dose and delivery system after 8 weeks post vaccination. Our findings show that fish vaccinated with less potent vaccines comprising of nanoparticle, DNA and recombinant vaccines got infected much earlier and yielded to higher infection rates than fish vaccinated with IWV vaccines that were highly potent. Ability of the virulent (T(217)A(221)) and avirulent (P(217)T(221)) motifs to limit establishment of infection showed equal protection for vaccines made of the same antigen dose and delivery systems. Prevention of tissue damage linked to viral infection was eminent in the more potent vaccines than the less protective ones. Hence, there still remains the challenge of developing highly efficacious vaccines with the ability to eliminate the post challenge carrier state in IPNV vaccinology. Copyright © 2012 Elsevier Ltd. All rights reserved.

Evaluating vaccination strategies to control foot-and-mouth disease: a model comparison study.

PubMed

Roche, S E; Garner, M G; Sanson, R L; Cook, C; Birch, C; Backer, J A; Dube, C; Patyk, K A; Stevenson, M A; Yu, Z D; Rawdon, T G; Gauntlett, F

2015-04-01

Simulation models can offer valuable insights into the effectiveness of different control strategies and act as important decision support tools when comparing and evaluating outbreak scenarios and control strategies. An international modelling study was performed to compare a range of vaccination strategies in the control of foot-and-mouth disease (FMD). Modelling groups from five countries (Australia, New Zealand, USA, UK, The Netherlands) participated in the study. Vaccination is increasingly being recognized as a potentially important tool in the control of FMD, although there is considerable uncertainty as to how and when it should be used. We sought to compare model outputs and assess the effectiveness of different vaccination strategies in the control of FMD. Using a standardized outbreak scenario based on data from an FMD exercise in the UK in 2010, the study showed general agreement between respective models in terms of the effectiveness of vaccination. Under the scenario assumptions, all models demonstrated that vaccination with 'stamping-out' of infected premises led to a significant reduction in predicted epidemic size and duration compared to the 'stamping-out' strategy alone. For all models there were advantages in vaccinating cattle-only rather than all species, using 3-km vaccination rings immediately around infected premises, and starting vaccination earlier in the control programme. This study has shown that certain vaccination strategies are robust even to substantial differences in model configurations. This result should increase end-user confidence in conclusions drawn from model outputs. These results can be used to support and develop effective policies for FMD control.

Plant-based anti-HIV-1 strategies: vaccine molecules and antiviral approaches.

PubMed

Scotti, Nunzia; Buonaguro, Luigi; Tornesello, Maria Lina; Cardi, Teodoro; Buonaguro, Franco Maria

2010-08-01

The introduction of highly active antiretroviral therapy has drastically changed HIV infection from an acute, very deadly, to a chronic, long-lasting, mild disease. However, this requires continuous care management, which is difficult to implement worldwide, especially in developing countries. Sky-rocketing costs of HIV-positive subjects and the limited success of preventive recommendations mean that a vaccine is urgently needed, which could be the only effective strategy for the real control of the AIDS pandemic. To be effective, vaccination will need to be accessible, affordable and directed against multiple antigens. Plant-based vaccines, which are easy to produce and administer, and require no cold chain for their heat stability are, in principle, suited to such a strategy. More recently, it has been shown that even highly immunogenic, enveloped plant-based vaccines can be produced at a competitive and more efficient rate than conventional strategies. The high variability of HIV epitopes and the need to stimulate both humoral neutralizing antibodies and cellular immunity suggest the importance of using the plant system: it offers a wide range of possible strategies, from single-epitope to multicomponent vaccines, modulators of the immune response (adjuvants) and preventive molecules (microbicides), either alone or in association with plant-derived monoclonal antibodies, besides the potential use of the latter as therapeutic agents. Furthermore, plant-based anti-HIV strategies can be administered not only parenterally but also by the more convenient and safer oral route, which is a more suitable approach for possible mass vaccination.

Potential Cost-Effectiveness of an Influenza Vaccination Program Offering Microneedle Patch for Vaccine Delivery in Children.

PubMed

Wong, Carlos; Jiang, Minghuan; You, Joyce H S

2016-01-01

The influenza vaccine coverage rate of children is low in Hong Kong. Microneedle patches (MNPs) is a technology under development for painless delivery of vaccines. This study aimed to examine the potential clinical outcomes and direct medical costs of an influenza program offering MNP vaccine to children who have declined intramuscular (IM) vaccine in Hong Kong. A decision model was designed to compare potential outcomes between IM vaccine program and a program offering MNP vaccine to those declined IM vaccine (IM/MNP program) in a hypothetical cohort of children over one-year time horizon. The model outcomes included direct medical cost, influenza infection rate, mortality rate, and quality-adjusted life-years (QALYs) loss. Model inputs were retrieved from published literature. Sensitivity analyses were performed to examine the robustness of model results. In base-case analysis, IM/MNP program was more costly per child (USD19.13 versus USD13.69; USD1 = HKD7.8) with lower influenza infection rate (98.9 versus 124.8 per 1,000 children), hospitalization rate (0.83 versus 1.05 per 1,000 children) and influenza-related mortality rate (0.00042 versus 0.00052 per 1,000 children) when compared to IM program. The incremental cost per QALY saved (ICER) of IM/MNP program versus IM program was 27,200 USD/QALY. Using gross domestic product (GDP) per capita of Hong Kong (USD40,594) as threshold of willingness-to-pay (WTP) per QALY, one-way sensitivity analysis found ICER of IM/MNP to exceed WTP when duration of illness in outpatient setting was <5.7 days or cost per MNP vaccine was >1.39-time of IM vaccine cost. In 10,000 Monte Carlo simulations, IM/MNP program was the preferred option in 57.28% and 91.68% of the time, using 1x and 3x GDP per capita as WTP threshold, respectively. Acceptance of IM/MNP program as the preferred program was subject to the WTP threshold, duration of illness in outpatient settings, and cost of MNP vaccine.

Progress towards development of an HIV vaccine: report of the AIDS Vaccine 2009 Conference.

PubMed

Ross, Anna Laura; Bråve, Andreas; Scarlatti, Gabriella; Manrique, Amapola; Buonaguro, Luigi

2010-05-01

The search for an HIV/AIDS vaccine is steadily moving ahead, generating and validating new concepts in terms of novel vectors for antigen delivery and presentation, new vaccine and adjuvant strategies, alternative approaches to design HIV-1 antigens for eliciting protective cross-neutralising antibodies, and identification of key mechanisms in HIV infection and modulation of the immune system. All these different perspectives are contributing to the unprecedented challenge of developing a protective HIV-1 vaccine. The high scientific value of this massive effort is its great impact on vaccinology as a whole, providing invaluable scientific information for the current and future development of new preventive vaccine as well as therapeutic knowledge-based infectious-disease and cancer vaccines. Copyright 2010 Elsevier Ltd. All rights reserved.

Porous nanoparticles as delivery system of complex antigens for an effective vaccine against acute and chronic Toxoplasma gondii infection.

PubMed

Dimier-Poisson, Isabelle; Carpentier, Rodolphe; N'Guyen, Thi Thanh Loi; Dahmani, Fatima; Ducournau, Céline; Betbeder, Didier

2015-05-01

Development of sub-unit mucosal vaccines requires the use of specific delivery systems or immune-modulators such as adjuvants to improve antigen immunogenicity. Nasal route for vaccine delivery by nanoparticles has attracted much interest but mechanisms triggering effective mucosal and systemic immune response are still poorly understood. Here we study the loading of porous nanoparticles (DGNP) with a total extract of Toxoplasma gondii antigens (TE), the delivery of TE by DGNP into airway epithelial, macrophage and dendritic cells, and the subsequent cellular activation. In vitro, DGNP are able to load complex antigens in a stable and quantitative manner. The outstanding amount of antigen association by DGNP is used to deliver TE in airway mucosa cells to induce a cellular maturation with an increased secretion of pro-inflammatory cytokines. Evaluation of nasal vaccine efficiency is performed in vivo on acute and chronic toxoplasmosis mouse models. A specific Th1/Th17 response is observed in vivo after vaccination with DGNP/TE. This is associated with high protection against toxoplasmosis regarding survival and parasite burden, correlated with an increased delivery of antigens by DGNP in airway mucosa cells. This study provides evidence of the potential of DGNP for the development of new vaccines against a range of pathogens. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mucosal Vaccination against Tuberculosis Using Inert Bioparticles

PubMed Central

Reljic, Rajko; Sibley, Laura; Huang, Jen-Min; Pepponi, Ilaria; Hoppe, Andreas; Hong, Huynh A.

2013-01-01

Needle-free, mucosal immunization is a highly desirable strategy for vaccination against many pathogens, especially those entering through the respiratory mucosa, such as Mycobacterium tuberculosis. Unfortunately, mucosal vaccination against tuberculosis (TB) is impeded by a lack of suitable adjuvants and/or delivery platforms that could induce a protective immune response in humans. Here, we report on a novel biotechnological approach for mucosal vaccination against TB that overcomes some of the current limitations. This is achieved by coating protective TB antigens onto the surface of inert bacterial spores, which are then delivered to the respiratory tract. Our data showed that mice immunized nasally with coated spores developed humoral and cellular immune responses and multifunctional T cells and, most importantly, presented significantly reduced bacterial loads in their lungs and spleens following pathogenic challenge. We conclude that this new vaccine delivery platform merits further development as a mucosal vaccine for TB and possibly also other respiratory pathogens. PMID:23959722

Bistability of Evolutionary Stable Vaccination Strategies in the Reinfection SIRI Model.

PubMed

Martins, José; Pinto, Alberto

2017-04-01

We use the reinfection SIRI epidemiological model to analyze the impact of education programs and vaccine scares on individuals decisions to vaccinate or not. The presence of the reinfection provokes the novelty of the existence of three Nash equilibria for the same level of the morbidity relative risk instead of a single Nash equilibrium as occurs in the SIR model studied by Bauch and Earn (PNAS 101:13391-13394, 2004). The existence of three Nash equilibria, with two of them being evolutionary stable, introduces two scenarios with relevant and opposite features for the same level of the morbidity relative risk: the low-vaccination scenario corresponding to the evolutionary stable vaccination strategy, where individuals will vaccinate with a low probability; and the high-vaccination scenario corresponding to the evolutionary stable vaccination strategy, where individuals will vaccinate with a high probability. We introduce the evolutionary vaccination dynamics for the SIRI model and we prove that it is bistable. The bistability of the evolutionary dynamics indicates that the damage provoked by false scares on the vaccination perceived morbidity risks can be much higher and much more persistent than in the SIR model. Furthermore, the vaccination education programs to be efficient they need to implement a mechanism to suddenly increase the vaccination coverage level.

Recent insights into cutaneous immunization: How to vaccinate via the skin.

PubMed

Engelke, Laura; Winter, Gerhard; Hook, Sarah; Engert, Julia

2015-09-08

Technologies and strategies for cutaneous vaccination have been evolving significantly during the past decades. Today, there is evidence for increased efficacy of cutaneously delivered vaccines allowing for dose reduction and providing a minimally invasive alternative to traditional vaccination. Considerable progress has been made within the field of well-established cutaneous vaccination strategies: Jet and powder injection technologies, microneedles, microporation technologies, electroporation, sonoporation, and also transdermal and transfollicular vaccine delivery. Due to recent advances, the use of cutaneous vaccination can be expanded from prophylactic vaccination for infectious diseases into therapeutic vaccination for both infectious and non-infectious chronic conditions. This review will provide an insight into immunological processes occurring in the skin and introduce the key innovations of cutaneous vaccination technologies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cost-effectiveness of three different vaccination strategies against measles in Zambian children.

PubMed

Dayan, Gustavo H; Cairns, Lisa; Sangrujee, Nalinee; Mtonga, Anne; Nguyen, Van; Strebel, Peter

2004-01-02

The vaccination program in Zambia includes one dose of measles vaccine at 9 months of age. The objective of this study was to compare the cost-effectiveness of the current one-dose measles vaccination program with an immunization schedule in which a second dose is provided either through routine health services or through supplemental immunization activities (SIAs). We simulated the expected cost and impact of the vaccination strategies for an annual cohort of 400,000 children, assuming 80% vaccination coverage in both routine and SIAs and an analytic horizon of 15 years. A vaccination program which includes SIAs reaching children not previously vaccinated would prevent on additional 29,242 measles cases and 1462 deaths for each vaccinated birth cohort when compared with a one-dose program. Given the parameters established for this analysis, such a program would be cost-saving and the most cost-effective vaccination strategy for Zambia.

[Is it ethically acceptable to invite a pregnant woman to enroll in a clinical trial with Tdap if it could entail not being vaccinated with Tdap before delivery?

PubMed

Dal-Ré, Rafael

2017-02-01

Pertussis incidence has increased in recent years, especially among infants aged <2months. A number of Spanish regions have started a vaccination program with Tdap vaccine to all pregnant women in the third trimester of pregnancy. An observational study has shown that this strategy reduces the number of cases of pertussis by 90% in infants aged <2months. Mathematical models showed that a cocooning strategy (i.e. vaccination of the mother at immediate postpartum, and other adults and adolescents who have close contact with the newborn and caregivers) will reduce the incidence of pertussis by 70% in infants aged <2months. It is intended to conduct a clinical trial in which 340 pregnant women will receive Tdap vaccine, whereas another 340 pregnant woman will be vaccinated soon after delivery. Vaccination with Tdap will be offered to all partners and caregivers of the newborn. After assessing both the ethical and scientific reasons supporting the trial, it is concluded that it is ethically and legally acceptable to invite pregnant women living in communities where Tdap vaccination has been implemented to participate in the trial. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Strategy for distribution of influenza vaccine to high-risk groups and children.

PubMed

Longini, Ira M; Halloran, M Elizabeth

2005-02-15

Despite evidence that vaccinating schoolchildren against influenza is effective in limiting community-level transmission, the United States has had a long-standing government strategy of recommending that vaccine be concentrated primarily in high-risk groups and distributed to those people who keep the health system and social infrastructure operating. Because of this year's influenza vaccine shortage, a plan was enacted to distribute the limited vaccine stock to these groups first. This vaccination strategy, based on direct protection of those most at risk, has not been very effective in reducing influenza morbidity and mortality. Although it is too late to make changes this year, the current influenza vaccine crisis affords the opportunity to examine an alternative for future years. The alternative plan, supported by mathematical models and influenza field studies, would be to concentrate vaccine in schoolchildren, the population group most responsible for transmission, while also covering the reachable high-risk groups, who would also receive considerable indirect protection. In conjunction with a plan to ensure an adequate vaccine supply, this alternative influenza vaccination strategy would help control interpandemic influenza and be instrumental in preparing for pandemic influenza. The effectiveness of the alternative plan could be assessed through nationwide community studies.

Nanoparticle based tailoring of adjuvant function: the role in vaccine development.

PubMed

Prashant, Chandravilas Keshvan; Kumar, Manoj; Dinda, Amit Kumar

2014-09-01

Vaccination is one of the most powerful therapeutic tools for prevention and management of various infective and non-infective diseases including malignancy. Mass vaccination is a great strategy for eradicating major infectious diseases throughout the world like small pox. Application of nanotechnology for antigen delivery is a unique area of research and development which can change the vaccination strategy and policy in future. Nanocarriers can enhance antigen presentation including modulation of antigen processing pathways according to the specific need. The current review explores the pros and cons of application of different nanomaterials for antigen presentation and vaccine development.

Potential impact of spatially targeted adult tuberculosis vaccine in Gujarat, India

PubMed Central

Chatterjee, Susmita; Rao, Krishna D.; Dowdy, David W.

2016-01-01

Some of the most promising vaccines in the pipeline for tuberculosis (TB) target adolescents and adults. Unlike for childhood vaccines, high-coverage population-wide vaccination is significantly more challenging for adult vaccines. Here, we aimed to estimate the impact of vaccine delivery strategies that were targeted to high-incidence geographical ‘hotspots’ compared with randomly allocated vaccination. We developed a spatially explicit mathematical model of TB transmission that distinguished these hotspots from the general population. We evaluated the impact of targeted and untargeted vaccine delivery strategies in India—a country that bears more than 25% of global TB burden, and may be a potential early adopter of the vaccine. We collected TB notification data and conducted a demonstration study in the state of Gujarat to validate our estimates of heterogeneity in TB incidence. We then projected the impact of randomly vaccinating 8% of adults in a single mass campaign to a spatially targeted vaccination preferentially delivered to 80% of adults in the hotspots, with both strategies augmented by continuous adolescent vaccination. In consultation with vaccine developers, we considered a vaccine efficacy of 60%, and evaluated the population-level impact after 10 years of vaccination. Spatial heterogeneity in TB notification (per 100 000/year) was modest in Gujarat: 190 in the hotspots versus 125 in the remaining population. At this level of heterogeneity, the spatially targeted vaccination was projected to reduce TB incidence by 28% after 10 years, compared with a 24% reduction projected to achieve via untargeted vaccination—a 1.17-fold augmentation in the impact of vaccination by spatially targeting. The degree of the augmentation was robust to reasonable variation in natural history assumptions, but depended strongly on the extent of spatial heterogeneity and mixing between the hotspot and general population. Identifying high-incidence hotspots and

Development of an acid-resistant Salmonella Typhi Ty21a attenuated vector for improved oral vaccine delivery

USDA-ARS?s Scientific Manuscript database

The licensed oral, live-attenuated bacterial vaccine for typhoid fever, Salmonella Typhi strain Ty21a, has also been utilized as a vaccine delivery platform for expression of diverse foreign antigens that stimulate protection against shigellosis, anthrax, plague, or human papilloma virus. However, T...

Macromolecular systems for vaccine delivery.

PubMed

MuŽíková, G; Laga, R

2016-10-20

Vaccines have helped considerably in eliminating some life-threatening infectious diseases in past two hundred years. Recently, human medicine has focused on vaccination against some of the world's most common infectious diseases (AIDS, malaria, tuberculosis, etc.), and vaccination is also gaining popularity in the treatment of cancer or autoimmune diseases. The major limitation of current vaccines lies in their poor ability to generate a sufficient level of protective antibodies and T cell responses against diseases such as HIV, malaria, tuberculosis and cancers. Among the promising vaccination systems that could improve the potency of weakly immunogenic vaccines belong macromolecular carriers (water soluble polymers, polymer particels, micelles, gels etc.) conjugated with antigens and immunistumulatory molecules. The size, architecture, and the composition of the high molecular-weight carrier can significantly improve the vaccine efficiency. This review includes the most recently developed (bio)polymer-based vaccines reported in the literature.

Comparing the health and social protection effects of measles vaccination strategies in Ethiopia: An extended cost-effectiveness analysis.

PubMed

Driessen, Julia; Olson, Zachary D; Jamison, Dean T; Verguet, Stéphane

2015-08-01

Vaccination coverage rates often mask wide variation in access, uptake, and cost of providing vaccination. Financial incentives have been effective at creating demand for social services in a variety of settings. Using methods of extended cost-effectiveness analysis, we compare the health and economic implications of three different vaccine delivery strategies for measles vaccination in Ethiopia: i) routine immunization, ii) routine immunization with financial incentives, and iii) mass campaigns, known as supplemental immunization activities (SIAs). We examine annual birth cohorts of almost 3,000,000 births over a ten year period, exploring variation in these outcomes based on economic status to understand how various options may improve equity. SIAs naturally achieve higher levels of vaccine coverage, but at higher costs. Routine immunization combined with financial incentives bolsters demand among more economically vulnerable households. The relative appeal of routine immunization with financial incentives and SIAs will depend on the policy environment, including short-term financial limitations, time horizons, and the types of outcomes that are desired. While the impact of financial incentives has been more thoroughly studied in other policy arenas, such as education, consideration of this approach alongside standard vaccination models such as SIAs is timely given the dialog around measles eradication. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Drug delivery strategies for Alzheimer's disease treatment.

PubMed

Di Stefano, Antonio; Iannitelli, Antonio; Laserra, Sara; Sozio, Piera

2011-05-01

Current Alzheimer's disease (AD) therapy is based on the administration of the drugs donepezil, galantamine, rivastigmine and memantine. Until disease-modifying therapies become available, further research is needed to develop new drug delivery strategies to ensure ease of administration and treatment persistence. In addition to the conventional oral formulations, a variety of drug delivery strategies applied to the treatment of AD are reviewed in this paper, with a focus on strategies leading to simplified dosage regimens and to providing new pharmacological tools. Alternatives include extended release, orally disintegrating or sublingual formulations, intranasal or short- and long-acting intramuscular or transdermal forms, and nanotechnology-based delivery systems. The advent of new research on molecular mechanisms of AD pathogenesis has outlined new strategies for therapeutic intervention; these include the stimulation of α-secretase cleavage, the inhibition of γ-secretase activity, the use of non-steroidal anti-inflammatory drugs, neuroprotection based on antioxidant therapy, the use of estrogens, NO synthetase inhibitors, and natural agents such as polyphenols. Unfortunately, these compounds might not help patients with end stage AD, but might hopefully slow or stop the disease process in its early stage. Nanotechnologies may prove to be a promising contribution in future AD drug delivery strategies, in particular drug carrier nano- or microsystems, which can limit the side effects of anti-Alzheimer drugs.

Enhancing Oral Vaccine Potency by Targeting Intestinal M Cells

PubMed Central

Azizi, Ali; Kumar, Ashok; Diaz-Mitoma, Francisco; Mestecky, Jiri

2010-01-01

The immune system in the gastrointestinal tract plays a crucial role in the control of infection, as it constitutes the first line of defense against mucosal pathogens. The attractive features of oral immunization have led to the exploration of a variety of oral delivery systems. However, none of these oral delivery systems have been applied to existing commercial vaccines. To overcome this, a new generation of oral vaccine delivery systems that target antigens to gut-associated lymphoid tissue is required. One promising approach is to exploit the potential of microfold (M) cells by mimicking the entry of pathogens into these cells. Targeting specific receptors on the apical surface of M cells might enhance the entry of antigens, initiating the immune response and consequently leading to protection against mucosal pathogens. In this article, we briefly review the challenges associated with current oral vaccine delivery systems and discuss strategies that might potentially target mouse and human intestinal M cells. PMID:21085599

Vaccine instability in the cold chain: mechanisms, analysis and formulation strategies.

PubMed

Kumru, Ozan S; Joshi, Sangeeta B; Smith, Dawn E; Middaugh, C Russell; Prusik, Ted; Volkin, David B

2014-09-01

Instability of vaccines often emerges as a key challenge during clinical development (lab to clinic) as well as commercial distribution (factory to patient). To yield stable, efficacious vaccine dosage forms for human use, successful formulation strategies must address a combination of interrelated topics including stabilization of antigens, selection of appropriate adjuvants, and development of stability-indicating analytical methods. This review covers key concepts in understanding the causes and mechanisms of vaccine instability including (1) the complex and delicate nature of antigen structures (e.g., viruses, proteins, carbohydrates, protein-carbohydrate conjugates, etc.), (2) use of adjuvants to further enhance immune responses, (3) development of physicochemical and biological assays to assess vaccine integrity and potency, and (4) stabilization strategies to protect vaccine antigens and adjuvants (and their interactions) during storage. Despite these challenges, vaccines can usually be sufficiently stabilized for use as medicines through a combination of formulation approaches combined with maintenance of an efficient cold chain (manufacturing, distribution, storage and administration). Several illustrative case studies are described regarding mechanisms of vaccine instability along with formulation approaches for stabilization within the vaccine cold chain. These include live, attenuated (measles, polio) and inactivated (influenza, polio) viral vaccines as well as recombinant protein (hepatitis B) vaccines. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

On the robust optimization to the uncertain vaccination strategy problem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaerani, D., E-mail: d.chaerani@unpad.ac.id; Anggriani, N., E-mail: d.chaerani@unpad.ac.id; Firdaniza, E-mail: d.chaerani@unpad.ac.id

2014-02-21

In order to prevent an epidemic of infectious diseases, the vaccination coverage needs to be minimized and also the basic reproduction number needs to be maintained below 1. This means that as we get the vaccination coverage as minimum as possible, thus we need to prevent the epidemic to a small number of people who already get infected. In this paper, we discuss the case of vaccination strategy in term of minimizing vaccination coverage, when the basic reproduction number is assumed as an uncertain parameter that lies between 0 and 1. We refer to the linear optimization model for vaccinationmore » strategy that propose by Becker and Starrzak (see [2]). Assuming that there is parameter uncertainty involved, we can see Tanner et al (see [9]) who propose the optimal solution of the problem using stochastic programming. In this paper we discuss an alternative way of optimizing the uncertain vaccination strategy using Robust Optimization (see [3]). In this approach we assume that the parameter uncertainty lies within an ellipsoidal uncertainty set such that we can claim that the obtained result will be achieved in a polynomial time algorithm (as it is guaranteed by the RO methodology). The robust counterpart model is presented.« less

Comparative effectiveness of different strategies of oral cholera vaccination in bangladesh: a modeling study.

PubMed

Dimitrov, Dobromir T; Troeger, Christopher; Halloran, M Elizabeth; Longini, Ira M; Chao, Dennis L

2014-12-01

Killed, oral cholera vaccines have proven safe and effective, and several large-scale mass cholera vaccination efforts have demonstrated the feasibility of widespread deployment. This study uses a mathematical model of cholera transmission in Bangladesh to examine the effectiveness of potential vaccination strategies. We developed an age-structured mathematical model of cholera transmission and calibrated it to reproduce the dynamics of cholera in Matlab, Bangladesh. We used the model to predict the effectiveness of different cholera vaccination strategies over a period of 20 years. We explored vaccination programs that targeted one of three increasingly focused age groups (the entire vaccine-eligible population of age one year and older, children of ages 1 to 14 years, or preschoolers of ages 1 to 4 years) and that could occur either as campaigns recurring every five years or as continuous ongoing vaccination efforts. Our modeling results suggest that vaccinating 70% of the population would avert 90% of cholera cases in the first year but that campaign and continuous vaccination strategies differ in effectiveness over 20 years. Maintaining 70% coverage of the population would be sufficient to prevent sustained transmission of endemic cholera in Matlab, while vaccinating periodically every five years is less effective. Selectively vaccinating children 1-14 years old would prevent the most cholera cases per vaccine administered in both campaign and continuous strategies. We conclude that continuous mass vaccination would be more effective against endemic cholera than periodic campaigns. Vaccinating children averts more cases per dose than vaccinating all age groups, although vaccinating only children is unlikely to control endemic cholera in Bangladesh. Careful consideration must be made before generalizing these results to other regions.

The expanding role of aerosols in systemic drug delivery, gene therapy, and vaccination.

PubMed

Laube, Beth L

2005-09-01

Aerosolized medications have been used for centuries to treat respiratory diseases. Until recently, inhalation therapy focused primarily on the treatment of asthma and chronic obstructive pulmonary disease, and the pressurized metered-dose inhaler was the delivery device of choice. However, the role of aerosol therapy is clearly expanding beyond that initial focus. This expansion has been driven by the Montreal protocol and the need to eliminate chlorofluorocarbons (CFCs) from traditional metered-dose inhalers, by the need for delivery devices and formulations that can efficiently and reproducibly target the systemic circulation for the delivery of proteins and peptides, and by developments in medicine that have made it possible to consider curing lung diseases with aerosolized gene therapy and preventing epidemics of influenza and measles with aerosolized vaccines. Each of these drivers has contributed to a decade or more of unprecedented research and innovation that has altered how we think about aerosol delivery and has expanded the role of aerosol therapy into the fields of systemic drug delivery, gene therapy, and vaccination. During this decade of innovation, we have witnessed the coming of age of dry powder inhalers, the development of new soft mist inhalers, and improved pressurized metered-dose inhaler delivery as a result of the replacement of CFC propellants with hydrofluoroalkane. The continued expansion of the role of aerosol therapy will probably depend on demonstration of the safety of this route of administration for drugs that have their targets outside the lung and are administered long term (eg, insulin aerosol), on the development of new drugs and drug carriers that can efficiently target hard-to-reach cell populations within the lungs of patients with disease (eg, patients with cystic fibrosis or lung cancer), and on the development of devices that improve aerosol delivery to infants, so that early intervention in disease processes with aerosol

Production of adenovirus vectors and their use as a delivery system for influenza vaccines

PubMed Central

Vemula, Sai V.; Mittal, Suresh K.

2010-01-01

IMPORTANCE OF THE FIELD With the emergence of highly pathogenic avian influenza H5N1 viruses that have crossed species barriers and are responsible for lethal infections in humans in many countries, there is an urgent need for the development of effective vaccines which can be produced in large quantities at a short notice and confer broad protection against these H5N1 variants. In order to meet the potential global vaccine demand in a pandemic scenario, new vaccine-production strategies must be explored in addition to the currently used egg-based technology for seasonal influenza. AREAS COVERED IN THIS REVIEW Adenovirus (Ad) based influenza vaccines represent an attractive alternative/supplement to the currently licensed egg-based influenza vaccines. Ad-based vaccines are relatively inexpensive to manufacture, and their production process does not require either chicken eggs or labor intensive and time-consuming processes necessitating enhanced biosafety facilities. Most importantly, in a pandemic situation, this vaccine strategy could offer a stockpiling option to reduce the response time before a strain-matched vaccine could be developed. WHAT THE READER WILL GAIN This review discusses Ad-vector technology and the current progress in the development of Ad-based influenza vaccines. TAKE HOME MESSAGE Ad vector-based influenza vaccines for pandemic preparedness are under development to meet the global vaccine demand. PMID:20822477

Oral cholera vaccine coverage in hard-to-reach fishermen communities after two mass Campaigns, Malawi, 2016.

PubMed

Sauvageot, Delphine; Saussier, Christel; Gobeze, Abebe; Chipeta, Sikhona; Mhango, Innocent; Kawalazira, Gift; Mengel, Martin A; Legros, Dominique; Cavailler, Philippe; M'bang'ombe, Maurice

2017-09-12

From December 2015 to August 2016, a large epidemic of cholera affected the fishermen of Lake Chilwa in Malawi. A first reactive Oral Cholera Vaccines (OCV) campaign was organized, in February, in a 2km radius of the lake followed by a preemptive one, conducted in November, in a 25km radius. We present the vaccine coverage reached in hard-to-reach population using simplified delivery strategies. We conducted two-stage random-sampling cross-sectional surveys among individuals living in a 2km and 25km radius of Lake Chilwa (islands and floating homes included). Individuals aged 12months and older from Machinga and Zomba districts were sampled: 43 clusters of 14 households were surveyed. Simplified strategies were used for those living in islands and floating homes: self- delivery and community-supervised delivery of the second dose. Vaccine coverage (VC) for at-least-two-doses was estimated taking into account sampling weights and design effects. A total of 1176 households were surveyed (2.7% of non-response). Among the 2833 individuals living in the 2km radius of Lake and the 2915 in the 25km radius: 457 (16.1%) and 239 (8.2%) lived in floating homes or on islands at some point in the year, respectively. For the overall population, VC was 75.6% and 54.2%, respectively. In the 2km radius, VC was 92.2% for those living on the lake at some point of the year: 271 (64.8%) used the simplified strategies. The main reasons for non-vaccination were absence during the campaign and vaccine shortage. Few adverse events occurring in the 24h following vaccination was reported. We reached a high two-dose coverage of the most at-risk population using simplified delivery strategies. Because of the high fishermen mobility, regular catch-up campaigns or another strategy specifically targeting fishermen need to be assessed for more efficient vaccines use. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Edible vaccines against veterinary parasitic diseases--current status and future prospects.

PubMed

Jacob, Siju S; Cherian, Susan; Sumithra, T G; Raina, O K; Sankar, M

2013-04-08

Protection of domestic animals against parasitic infections remains a major challenge in most of the developing countries, especially in the surge of drug resistant strains. In this circumstance vaccination seems to be the sole practical strategy to combat parasites. Most of the presently available live or killed parasitic vaccines possess many disadvantages. Thus, expression of parasitic antigens has seen a continued interest over the past few decades. However, only a limited success was achieved using bacterial, yeast, insect and mammalian expression systems. This is witnessed by an increasing number of reports on transgenic plant expression of previously reported and new antigens. Oral delivery of plant-made vaccines is particularly attractive due to their exceptional advantages. Moreover, the regulatory burden for veterinary vaccines is less compared to human vaccines. This led to an incredible investment in the field of transgenic plant vaccines for veterinary purpose. Plant based vaccine trials have been conducted to combat various significant parasitic diseases such as fasciolosis, schistosomosis, poultry coccidiosis, porcine cycticercosis and ascariosis. Besides, passive immunization by oral delivery of antibodies expressed in transgenic plants against poultry coccidiosis is an innovative strategy. These trials may pave way to the development of promising edible veterinary vaccines in the near future. As the existing data regarding edible parasitic vaccines are scattered, an attempt has been made to assemble the available literature. Copyright © 2013 Elsevier Ltd. All rights reserved.

The introduction of new vaccines into developing countries. IV: Global Access Strategies.

PubMed

Mahoney, Richard T; Krattiger, Anatole; Clemens, John D; Curtiss, Roy

2007-05-16

This paper offers a framework for managing a comprehensive Global Access Strategy for new vaccines in developing countries. It is aimed at strengthening the ability of public-sector entities to reach their goals. The Bill and Melinda Gates Foundation and The Rockefeller Foundation have been leaders in stimulating the creation of new organizations - public/private product development partnerships (PDPs) - that seek to accelerate vaccine development and distribution to meet the health needs of the world's poor. Case studies of two of these PDPs - the Salmonella Anti-pneumococcal Vaccine Program and the Pediatric Dengue Vaccine Initiative - examine development of such strategies. Relying on the application of innovation theory, the strategy leads to the identification of six Components of Innovation which cover all aspects of the vaccine innovation process. Appropriately modified, the proposed framework can be applied to the development and introduction of other products in developing countries including drugs, and nutritional and agricultural products.

Virus-like particles as a vaccine delivery system: myths and facts.

PubMed

Roy, Polly; Noad, Rob

2009-01-01

Vaccines against viral disease have traditionally relied on attenuated virus strains or inactivation of infectious virus. Subunit vaccines based on viral proteins expressed in heterologous systems have been effective for some pathogens, but have often suffered from poor immunogenicity due to incorrect protein folding or modification. In this chapter we focus on a specific class of viral subunit vaccine that mimics the overall structure of virus particles and thus preserves the native antigenic conformation of the immunogenic proteins. These virus-like particles (VLPs) have been produced for a wide range of taxonomically and structurally distinct viruses, and have unique advantages in terms of safety and immunogenicity over previous approaches. With new VLP vaccines for papillomavirus beginning to reach the market place we argue that this technology has now 'come-of-age' and must be considered a viable vaccine strategy.

Photochemical Internalization of Peptide Antigens Provides a Novel Strategy to Realize Therapeutic Cancer Vaccination

PubMed Central

Haug, Markus; Brede, Gaute; Håkerud, Monika; Nedberg, Anne Grete; Gederaas, Odrun A.; Flo, Trude H.; Edwards, Victoria T.; Selbo, Pål K.; Høgset, Anders; Halaas, Øyvind

2018-01-01

Effective priming and activation of tumor-specific CD8+ cytotoxic T lymphocytes (CTLs) is crucial for realizing the potential of therapeutic cancer vaccination. This requires cytosolic antigens that feed into the MHC class I presentation pathway, which is not efficiently achieved with most current vaccination technologies. Photochemical internalization (PCI) provides an emerging technology to route endocytosed material to the cytosol of cells, based on light-induced disruption of endosomal membranes using a photosensitizing compound. Here, we investigated the potential of PCI as a novel, minimally invasive, and well-tolerated vaccination technology to induce priming of cancer-specific CTL responses to peptide antigens. We show that PCI effectively promotes delivery of peptide antigens to the cytosol of antigen-presenting cells (APCs) in vitro. This resulted in a 30-fold increase in MHC class I/peptide complex formation and surface presentation, and a subsequent 30- to 100-fold more efficient activation of antigen-specific CTLs compared to using the peptide alone. The effect was found to be highly dependent on the dose of the PCI treatment, where optimal doses promoted maturation of immature dendritic cells, thus also providing an adjuvant effect. The effect of PCI was confirmed in vivo by the successful induction of antigen-specific CTL responses to cancer antigens in C57BL/6 mice following intradermal peptide vaccination using PCI technology. We thus show new and strong evidence that PCI technology holds great potential as a novel strategy for improving the outcome of peptide vaccines aimed at triggering cancer-specific CD8+ CTL responses. PMID:29670624

Comparative Effectiveness of Different Strategies of Oral Cholera Vaccination in Bangladesh: A Modeling Study

PubMed Central

Dimitrov, Dobromir T.; Troeger, Christopher; Halloran, M. Elizabeth; Longini, Ira M.; Chao, Dennis L.

2014-01-01

Background Killed, oral cholera vaccines have proven safe and effective, and several large-scale mass cholera vaccination efforts have demonstrated the feasibility of widespread deployment. This study uses a mathematical model of cholera transmission in Bangladesh to examine the effectiveness of potential vaccination strategies. Methods & Findings We developed an age-structured mathematical model of cholera transmission and calibrated it to reproduce the dynamics of cholera in Matlab, Bangladesh. We used the model to predict the effectiveness of different cholera vaccination strategies over a period of 20 years. We explored vaccination programs that targeted one of three increasingly focused age groups (the entire vaccine-eligible population of age one year and older, children of ages 1 to 14 years, or preschoolers of ages 1 to 4 years) and that could occur either as campaigns recurring every five years or as continuous ongoing vaccination efforts. Our modeling results suggest that vaccinating 70% of the population would avert 90% of cholera cases in the first year but that campaign and continuous vaccination strategies differ in effectiveness over 20 years. Maintaining 70% coverage of the population would be sufficient to prevent sustained transmission of endemic cholera in Matlab, while vaccinating periodically every five years is less effective. Selectively vaccinating children 1–14 years old would prevent the most cholera cases per vaccine administered in both campaign and continuous strategies. Conclusions We conclude that continuous mass vaccination would be more effective against endemic cholera than periodic campaigns. Vaccinating children averts more cases per dose than vaccinating all age groups, although vaccinating only children is unlikely to control endemic cholera in Bangladesh. Careful consideration must be made before generalizing these results to other regions. PMID:25473851

Potent Immunity to Low Doses of Influenza Vaccine by Probabilistic Guided Micro-Targeted Skin Delivery in a Mouse Model

PubMed Central

Prow, Tarl W.; Crichton, Michael L.; Fairmaid, Emily J.; Roberts, Michael S.; Frazer, Ian H.; Brown, Lorena E.; Kendall, Mark A. F.

2010-01-01

Background Over 14 million people die each year from infectious diseases despite extensive vaccine use [1]. The needle and syringe—first invented in 1853—is still the primary delivery device, injecting liquid vaccine into muscle. Vaccines could be far more effective if they were precisely delivered into the narrow layer just beneath the skin surface that contains a much higher density of potent antigen-presenting cells (APCs) essential to generate a protective immune response. We hypothesized that successful vaccination could be achieved this way with far lower antigen doses than required by the needle and syringe. Methodology/Principal Findings To meet this objective, using a probability-based theoretical analysis for targeting skin APCs, we designed the Nanopatch™, which contains an array of densely packed projections (21025/cm2) invisible to the human eye (110 µm in length, tapering to tips with a sharpness of <1000 nm), that are dry-coated with vaccine and applied to the skin for two minutes. Here we show that the Nanopatches deliver a seasonal influenza vaccine (Fluvax® 2008) to directly contact thousands of APCs, in excellent agreement with theoretical prediction. By physically targeting vaccine directly to these cells we induced protective levels of functional antibody responses in mice and also protection against an influenza virus challenge that are comparable to the vaccine delivered intramuscularly with the needle and syringe—but with less than 1/100th of the delivered antigen. Conclusions/Significance Our results represent a marked improvement—an order of magnitude greater than reported by others—for injected doses administered by other delivery methods, without reliance on an added adjuvant, and with only a single vaccination. This study provides a proven mathematical/engineering delivery device template for extension into human studies—and we speculate that successful translation of these findings into humans could uniquely assist with

Opportunity for catch-up HPV vaccination in young women after first delivery.

PubMed

Rama, Cristina Helena; Villa, Luisa L; Pagliusi, Sonia; Andreoli, Maria A; Costa, Maria C; Thomann, Patricia; Alves, Venancio A F; Longatto-Filho, Adhemar; Eluf-Neto, Jose

2010-07-01

Early age at first delivery has been identified as a risk factor for high-risk HPV-type infection and cervical cancer development. A cross-sectional study was carried out in a large public maternity hospital in São Paulo, Brazil. During June 2006 to February 2007, 301 women aged 15-24 years who gave birth to their first child were recruited between 43 and 60 days after delivery. Detection of HPV DNA in cervical specimens was performed using a standardised PCR protocol with PGMY09/11 primers. The association of selected factors with HPV infection was assessed by using a Generalised Linear Model. HPV DNA was detected in 58.5% (95% CI 52.7% to 64.0%) of the enrolled young women. The most common types of HPV found were: HPV16, HPV51, HPV52, HPV58 and HPV71. The overall prevalence of HPV types targeted by the HPV prophylactic vaccines was: HPV 16-12.0%, HPV 18- 2.3% and HPV 6 and 11 4.3%. In the multivariate analysis, only age (inversely, p for trend=0.02) and smoking habits were independently associated with HPV infection. The findings show that these young primiparous women had high cervical HPV prevalence, suggesting that this is a high-risk group for cervical cancer development. Nevertheless, 17.3% were positive for any of the four HPV types included in HPV vaccines (HPV6, 11, 16 or 18), with 13.3% positive for HPV 16 or 18 and only 1.0% having both vaccine related-oncogenic HPV types. Thus, young primiparous women could benefit from catch-up HPV vaccination programmes.

Ternary particles for effective vaccine delivery to the pulmonary system

NASA Astrophysics Data System (ADS)

Terry, Treniece La'shay

Progress in the fields of molecular biology and genomics has provided great insight into the pathogenesis of disease and the defense mechanisms of the immune system. This knowledge has lead to the classification of an array of abnormal genes, for which, treatment relies on cellular expression of proteins. The utility of DNA-based vaccines hold great promise for the treatment of genetically based and infectious diseases, which ranges from hemophilia, cystic fibrosis, and HIV. Synthetic delivery systems consisting of cationic polymers, such as polyethylenimine (PEI), are capable of condensing DNA into compact structures, maximizing cellular uptake of DNA and yielding high levels of protein expression. To date, short term expression is a major obstacle in the development of gene therapies and has halted their expansion in clinical applications. This study intends to develop a sustained release vaccine delivery system using PLA-PEG block copolymers encapsulating PEI:DNA polyplexes. To enhance the effectiveness of such DNA-based vaccines, resident antigen presenting cells, macrophages and dendritic cells, will be targeted within the alveoli regions of the lungs. Porous microspheres will be engineered with aerodynamic properties capable of achieving deep lung deposition. A fabrication technique using concentric nozzles will be developed to produce porous microspheres. It was observed that modifications in the dispersed to continuous phase ratios have the largest influence on particle size distributions, release rates and encapsulation efficiency which ranged form 80--95% with fourteen days of release. Amphiphilic block copolymers were also used to fabricate porous microspheres. The confirmation of PEG within the biodegradable polymer backbone was found to have a tremendous impact on the microsphere morphology and encapsulation efficiency which varied from 50--90%. Porous microspheres were capable of providing sustained gene expression when tested in vitro using the

Vaccines: From Empirical Development to Rational Design

PubMed Central

Rueckert, Christine; Guzmán, Carlos A.

2012-01-01

Infectious diseases are responsible for an overwhelming number of deaths worldwide and their clinical management is often hampered by the emergence of multi-drug-resistant strains. Therefore, prevention through vaccination currently represents the best course of action to combat them. However, immune escape and evasion by pathogens often render vaccine development difficult. Furthermore, most currently available vaccines were empirically designed. In this review, we discuss why rational design of vaccines is not only desirable but also necessary. We introduce recent developments towards specifically tailored antigens, adjuvants, and delivery systems, and discuss the methodological gaps and lack of knowledge still hampering true rational vaccine design. Finally, we address the potential and limitations of different strategies and technologies for advancing vaccine development. PMID:23144616

HIV/AIDS vaccines for Africa: scientific opportunities, challenges and strategies

PubMed Central

Chin'ombe, Nyasha; Ruhanya, Vurayai

2015-01-01

More than decades have already elapsed since human immunodeficiency virus (HIV) was identified as the causative agent of acquired immunodeficiency syndrome (AIDS). The HIV has since spread to all parts of the world with devastating effects. In sub-saharan Africa, the HIV/AIDS epidemic has reached unprecedented proportions. Safe, effective and affordable HIV/AIDS vaccines for Africans are therefore urgently needed to contain this public health problem. Although, there are challenges, there are also scientific opportunities and strategies that can be exploited in the development of HIV/AIDS vaccines for Africa. The recent RV144 Phase III trial in Thailand has demonstrated that it is possible to develop a vaccine that can potentially elicit modest protective immunity against HIV infection. The main objective of this review is to outline the key scientific opportunities, challenges and strategies in HIV/AIDS vaccine development in Africa. PMID:26185576

Strategies for Improving Vaccine Delivery: A Cluster-Randomized Trial.

PubMed

Fu, Linda Y; Zook, Kathleen; Gingold, Janet A; Gillespie, Catherine W; Briccetti, Christine; Cora-Bramble, Denice; Joseph, Jill G; Haimowitz, Rachel; Moon, Rachel Y

2016-06-01

New emphasis on and requirements for demonstrating health care quality have increased the need for evidence-based methods to disseminate practice guidelines. With regard to impact on pediatric immunization coverage, we aimed to compare a financial incentive program (pay-for-performance [P4P]) and a virtual quality improvement technical support (QITS) learning collaborative. This single-blinded (to outcomes assessor), cluster-randomized trial was conducted among unaffiliated pediatric practices across the United States from June 2013 to June 2014. Practices received either the P4P or QITS intervention. All practices received a Vaccinator Toolkit. P4P practices participated in a tiered financial incentives program for immunization coverage improvement. QITS practices participated in a virtual learning collaborative. Primary outcome was percentage of all needed vaccines received (PANVR). We also assessed immunization up-to-date (UTD) status. Data were analyzed from 3,147 patient records from 32 practices. Practices in the study arms reported similar QI activities (∼6 to 7 activities). We found no difference in PANVR between P4P and QITS (mean ± SE, 90.7% ± 1.1% vs 86.1% ± 1.3%, P = 0.46). Likewise, there was no difference in odds of being UTD between study arms (adjusted odds ratio 1.02, 95% confidence interval 0.68 to 1.52, P = .93). In within-group analysis, patients in both arms experienced nonsignificant increases in PANVR. Similarly, the change in adjusted odds of UTD over time was modest and nonsignificant for P4P but reached significance in the QITS arm (adjusted odds ratio 1.28, 95% confidence interval 1.02 to 1.60, P = .03). Participation in either a financial incentives program or a virtual learning collaborative led to self-reported improvements in immunization practices but minimal change in objectively measured immunization coverage. Copyright © 2016 by the American Academy of Pediatrics.

Maternal vaccination as a Salmonella Typhimurium reduction strategy on pig farms.

PubMed

Smith, R P; Andres, V; Martelli, F; Gosling, B; Marco-Jimenez, F; Vaughan, K; Tchorzewska, M; Davies, R

2018-01-01

The control of Salmonella in pig production is necessary for public and animal health, and vaccination was evaluated as a strategy to decrease pig prevalence. The study examined the efficacy of a live Salmonella Typhimurium vaccine, administered to sows on eight commercial farrow-to-finish herds experiencing clinical salmonellosis or Salmonella carriage associated with S. Typhimurium or its monophasic variants. Results of longitudinal Salmonella sampling were compared against eight similarly selected and studied control farms. At the last visit (~14 months after the start of vaccination), when all finishing stock had been born to vaccinated sows, both faecal shedding and environmental prevalence of Salmonella substantially declined on the majority of vaccinated farms in comparison to the controls. A higher proportion of vaccine farms resolved clinical salmonellosis than controls. However, Salmonella counts in positive faeces samples were similar between nonvaccinated and vaccinated herds. The results suggest that maternal vaccination is a suitable option for a Salmonella Typhimurium reduction strategy in farrow-to-finish pig herds. Salmonella vaccines have the potential to reduce the prevalence of Salmonella in pigs and result in a reduction of human cases attributed to pork. © 2017 Crown copyright. Journal of Applied Microbiology © 2017 The Society for Applied Microbiology. This article is published with the permission of the Controller of HMSO and the Queen’s Printer for Scotland.

Comparison of two vaccination strategies against hepatitis A and B in patients with chronic hepatitis C.

PubMed

Díez Redondo, M P; Almaraz, A; Jiménez Rodríguez-Vila, M; Santamaría, A; de Castro, J; Torrego, J C; Caro-Patón, A

2009-04-01

although the vaccination against hepatitis A (VAH) and hepatitis B (VBH) is recommended in patients with HCV, the most cost-effective strategy has not been established. Our objective was to compare the cost-effectiveness of universal strategy (vaccination all patients) with selective strategy (vaccination only patients against virus they lack immunity to) in patients with HCV. we compared the direct medical costs of the two vaccination strategies against both viruses in 313 patients with HC. Serological markers for HAV (anti-HAV) and HBV (HbsAg, anti HBs, anti HBc) were determined in the 313 patients and the costs of the vaccines and the blood tests necessary to determinate the immunity state in our care system were considered. the prevalence of anti-HAV was 81,2% and of anti-HBc was 24,6%. The prevalence of anti-HAV increases with age. HAV vaccination with universal strategy has a cost of 19.806,64 euro and with selective one of 9.899,62 euro. HBV vaccination with universal strategy rose to 18.780 euro and to 20.385,57 euro with selective one (employing anti-HBc). Costs were analysed in different groups of age and several hepatitis HBV risk factors. the selective vaccination strategy against HAV was most cost-effective in our patients with HCV. However, when the prevalence of the anti-HAV decreased to less than 20% universal strategy will be the best option. Difference of cost-effective between the two vaccination strategies against HBV was small, on behalf of universal one, so in groups with higher anti-HBc prevalence, like parenteral drugs users and tattoos, the selective strategy could be the best option.

Strategies to Improve Vaccine Efficacy against Tuberculosis by Targeting Innate Immunity

PubMed Central

Schaible, Ulrich E.; Linnemann, Lara; Redinger, Natalja; Patin, Emmanuel C.; Dallenga, Tobias

2017-01-01

The global tuberculosis epidemic is the most common cause of death after infectious disease worldwide. Increasing numbers of infections with multi- and extensively drug-resistant variants of the Mycobacterium tuberculosis complex, resistant even to newly discovered and last resort antibiotics, highlight the urgent need for an efficient vaccine. The protective efficacy to pulmonary tuberculosis in adults of the only currently available vaccine, M. bovis BCG, is unsatisfactory and geographically diverse. More importantly, recent clinical studies on new vaccine candidates did not prove to be better than BCG, yet. Here, we propose and discuss novel strategies to improve efficacy of existing anti-tuberculosis vaccines. Modulation of innate immune responses upon vaccination already provided promising results in animal models of tuberculosis. For instance, neutrophils have been shown to influence vaccine efficacy, both, positively and negatively, and stimulate specific antibody secretion. Modulating immune regulatory properties after vaccination such as induction of different types of innate immune cell death, myeloid-derived suppressor or regulatory T cells, production of anti-inflammatory cytokines such as IL-10 may have beneficial effects on protection efficacy. Incorporation of lipid antigens presented via CD1 molecules to T cells have been discussed as a way to enhance vaccine efficacy. Finally, concepts of dendritic cell-based immunotherapies or training the innate immune memory may be exploitable for future vaccination strategies against tuberculosis. In this review, we put a spotlight on host immune networks as potential targets to boost protection by old and new tuberculosis vaccines. PMID:29312298

Strategies to Improve Vaccine Efficacy against Tuberculosis by Targeting Innate Immunity.

PubMed

Schaible, Ulrich E; Linnemann, Lara; Redinger, Natalja; Patin, Emmanuel C; Dallenga, Tobias

2017-01-01

The global tuberculosis epidemic is the most common cause of death after infectious disease worldwide. Increasing numbers of infections with multi- and extensively drug-resistant variants of the Mycobacterium tuberculosis complex, resistant even to newly discovered and last resort antibiotics, highlight the urgent need for an efficient vaccine. The protective efficacy to pulmonary tuberculosis in adults of the only currently available vaccine, M. bovis BCG, is unsatisfactory and geographically diverse. More importantly, recent clinical studies on new vaccine candidates did not prove to be better than BCG, yet. Here, we propose and discuss novel strategies to improve efficacy of existing anti-tuberculosis vaccines. Modulation of innate immune responses upon vaccination already provided promising results in animal models of tuberculosis. For instance, neutrophils have been shown to influence vaccine efficacy, both, positively and negatively, and stimulate specific antibody secretion. Modulating immune regulatory properties after vaccination such as induction of different types of innate immune cell death, myeloid-derived suppressor or regulatory T cells, production of anti-inflammatory cytokines such as IL-10 may have beneficial effects on protection efficacy. Incorporation of lipid antigens presented via CD1 molecules to T cells have been discussed as a way to enhance vaccine efficacy. Finally, concepts of dendritic cell-based immunotherapies or training the innate immune memory may be exploitable for future vaccination strategies against tuberculosis. In this review, we put a spotlight on host immune networks as potential targets to boost protection by old and new tuberculosis vaccines.

Rabies control in rural Africa: Evaluating strategies for effective domestic dog vaccination

PubMed Central

Kaare, M.; Lembo, T.; Hampson, K.; Ernest, E.; Estes, A.; Mentzel, C.; Cleaveland, S.

2012-01-01

Effective vaccination campaigns need to reach a sufficient percentage of the population to eliminate disease and prevent future outbreaks, which for rabies is predicted to be 70%, at a cost that is economically and logistically sustainable. Domestic dog rabies has been increasing across most of sub-Saharan Africa indicating that dog vaccination programmes to date have been inadequate. We compare the effectiveness of a variety of dog vaccination strategies in terms of their cost and coverage in different community settings in rural Tanzania. Central-point (CP) vaccination was extremely effective in agro-pastoralist communities achieving a high coverage (>80%) at a low cost (vaccination was costly (>US$5/dog) and inadequate (<20% coverage); combined approaches using CP and either house-to-house vaccination or trained community-based animal health workers were most effective with coverage exceeding 70%, although costs were still high (>US$6 and >US$4/dog, respectively). No single vaccination strategy is likely to be effective in all populations and therefore alternative approaches must be deployed under different settings. CP vaccination is cost-effective and efficient for the majority of dog populations in rural Tanzania and potentially elsewhere in sub-Saharan Africa, whereas a combination strategy is necessary in remote pastoralist communities. These results suggest that rabies control is logistically feasible across most of the developing world and that the annual costs of effective vaccination campaigns in Tanzania are likely to be affordable. PMID:18848595

Tattoo Delivery of a Semliki Forest Virus-Based Vaccine Encoding Human Papillomavirus E6 and E7.

PubMed

van de Wall, Stephanie; Walczak, Mateusz; van Rooij, Nienke; Hoogeboom, Baukje-Nynke; Meijerhof, Tjarko; Nijman, Hans W; Daemen, Toos

2015-03-24

The skin is an attractive organ for immunization because of the presence of antigen-presenting cells. Intradermal delivery via tattooing has demonstrated superior vaccine immunogenicity of DNA vaccines in comparison to conventional delivery methods. In this study, we explored the efficacy of tattoo injection of a tumor vaccine based on recombinant Semliki Forest virus replicon particles (rSFV) targeting human papillomavirus (HPV). Tattoo injection of rSFV particles resulted in antigen expression in both the skin and draining lymph nodes. In comparison with intramuscular injection, the overall antigen expression determined at the site of administration and draining lymph nodes was 10-fold lower upon tattoo injection. Delivery of SFV particles encoding the E6 and E7 antigens of human papillomavirus type 16 (SFVeE6,7) via tattooing resulted in HPV-specific cytotoxic T cells and in vivo therapeutic antitumor response. Strikingly, despite the observed lower overall transgene expression, SFVeE6,7 delivered via tattoo injection resulted in higher or equal levels of immune responses as compared to intramuscular injection. The intrinsic immunogenic potential of tattooing provides a benefit for immunotherapy based on an alphavirus.

Tattoo Delivery of a Semliki Forest Virus-Based Vaccine Encoding Human Papillomavirus E6 and E7

PubMed Central

van de Wall, Stephanie; Walczak, Mateusz; van Rooij, Nienke; Hoogeboom, Baukje-Nynke; Meijerhof, Tjarko; Nijman, Hans W.; Daemen, Toos

2015-01-01

The skin is an attractive organ for immunization because of the presence of antigen-presenting cells. Intradermal delivery via tattooing has demonstrated superior vaccine immunogenicity of DNA vaccines in comparison to conventional delivery methods. In this study, we explored the efficacy of tattoo injection of a tumor vaccine based on recombinant Semliki Forest virus replicon particles (rSFV) targeting human papillomavirus (HPV). Tattoo injection of rSFV particles resulted in antigen expression in both the skin and draining lymph nodes. In comparison with intramuscular injection, the overall antigen expression determined at the site of administration and draining lymph nodes was 10-fold lower upon tattoo injection. Delivery of SFV particles encoding the E6 and E7 antigens of human papillomavirus type 16 (SFVeE6,7) via tattooing resulted in HPV-specific cytotoxic T cells and in vivo therapeutic antitumor response. Strikingly, despite the observed lower overall transgene expression, SFVeE6,7 delivered via tattoo injection resulted in higher or equal levels of immune responses as compared to intramuscular injection. The intrinsic immunogenic potential of tattooing provides a benefit for immunotherapy based on an alphavirus. PMID:26343186

Single-walled carbon nanotubes as delivery vehicles enhance the immunoprotective effects of a recombinant vaccine against Aeromonas hydrophila.

PubMed

Gong, Yu-Xin; Zhu, Bin; Liu, Guang-Lu; Liu, Lei; Ling, Fei; Wang, Gao-Xue; Xu, Xin-Gang

2015-01-01

To reduce the economic losses caused by diseases in aquaculture industry, more efficient and economic prophylactic measures should be urgently investigated. In this research, the effects of a novel functionalized single-walled carbon nanotubes (SWCNTs) applied as a delivery vehicle for recombinant Aeromonas hydrophila vaccine administration via bath or injection in juvenile grass carp were studied. The results showed that SWCNT as a vector for the recombinant protein aerA, augmented the production of specific antibodies, apparently stimulated the induction of immune-related genes, and induced higher level of survival rate compared with free aerA subunit vaccine. Furthermore, we compared the routes of bath and intramuscular injection immunization by SWCNTs-aerA vaccine, and found that similar antibody levels induced by SWCNTs-aerA were observed in both immunization routes. Meanwhile, a similar relative percentage survival (approximately 80%) was found in both a 40 mg/L bath immunization group, and a 20 μg injection group. The results indicate that functionalized SWCNTs could be a promising delivery vehicle to potentiate the immune response of recombinant vaccines, and might be used to vaccinate juvenile fish by bath administration method. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biomaterials at the interface of nano- and micro-scale vector-cellular interactions in genetic vaccine design.

PubMed

Jones, Charles H; Hakansson, Anders P; Pfeifer, Blaine A

2014-01-01

The development of safe and effective vaccines for the prevention of elusive infectious diseases remains a public health priority. Immunization, characterized by adaptive immune responses to specific antigens, can be raised by an array of delivery vectors. However, current commercial vaccination strategies are predicated on the retooling of archaic technology. This review will discuss current and emerging strategies designed to elicit immune responses in the context of genetic vaccination. Selected strategies at the biomaterial-biological interface will be emphasized to illustrate the potential of coupling both fields towards a common goal.

Lessons learnt from human papillomavirus (HPV) vaccination in 45 low- and middle-income countries.

PubMed

Gallagher, Katherine E; Howard, Natasha; Kabakama, Severin; Mounier-Jack, Sandra; Griffiths, Ulla K; Feletto, Marta; Burchett, Helen E D; LaMontagne, D Scott; Watson-Jones, Deborah

2017-01-01

To synthesise lessons learnt and determinants of success from human papillomavirus (HPV) vaccine demonstration projects and national programmes in low- and middle-income countries (LAMICs). Interviews were conducted with 56 key informants. A systematic literature review identified 2936 abstracts from five databases; after screening 61 full texts were included. Unpublished literature, including evaluation reports, was solicited from country representatives; 188 documents were received. A data extraction tool and interview topic guide outlining key areas of inquiry were informed by World Health Organization guidelines for new vaccine introduction. Results were synthesised thematically. Data were analysed from 12 national programmes and 66 demonstration projects in 46 countries. Among demonstration projects, 30 were supported by the GARDASIL® Access Program, 20 by Gavi, four by PATH and 12 by other means. School-based vaccine delivery supplemented with health facility-based delivery for out-of-school girls attained high coverage. There were limited data on facility-only strategies and little evaluation of strategies to reach out-of-school girls. Early engagement of teachers as partners in social mobilisation, consent, vaccination day coordination, follow-up of non-completers and adverse events was considered invaluable. Micro-planning using school/ facility registers most effectively enumerated target populations; other estimates proved inaccurate, leading to vaccine under- or over-estimation. Refresher training on adverse events and safe injection procedures was usually necessary. Considerable experience in HPV vaccine delivery in LAMICs is available. Lessons are generally consistent across countries and dissemination of these could improve HPV vaccine introduction.

Particle based vaccine formulations for transcutaneous immunization.

PubMed

Mittal, Ankit; Raber, Anne S; Lehr, Claus-Michael; Hansen, Steffi

2013-09-01

Vaccine formulations on the basis of nano- (NP) or microparticles (MP) can solve issues with stabilization, controlled release, and poor immunogenicity of antigens. Likewise transcutaneous immunization (TCI) promises superior immunogenicity as well as the advantages of needle-free application compared with conventional intramuscular injections. Thus the combination of both strategies seems to be a very valuable approach. However, until now TCI using particle based vaccine formulations has made no impact on medical practice. One of the main difficulties is that NPs and MPs cannot penetrate the skin to an extent that would allow the application of the required dose of antigen. This is due to the formidable stratum corneum (SC) barrier, the limited amount of antigen in the formulation and often an insufficient immunogenicity. A multitude of strategies are currently under investigation to overcome these issues. We highlight selected methods presenting a spectrum of solutions ranging from transfollicular delivery, to devices disrupting the SC barrier and the combination of particle based vaccines with adjuvants discussing their advantages and shortcomings. Some of these are currently at an experimental state while others are already in clinical testing. All methods have been shown to be capable of transcutaneous antigen delivery.

A proposed national strategy for tuberculosis vaccine development.

PubMed

Ginsberg, A M

2000-06-01

The global tuberculosis epidemic causes approximately 5% of deaths worldwide. Despite recent concerted and largely successful tuberculosis control efforts, the incidence of tuberculosis in the United States remains 74-fold higher than the stated elimination goal of <1 case per million population by the year 2010. Current bacille Calmette-Guérin vaccines, although efficacious in preventing extrapulmonary tuberculosis in young children, have shown widely variable efficacy in preventing adult pulmonary tuberculosis, confound skin test screening, and are not recommended for use in the United States. The Advisory Council for Elimination of Tuberculosis recently stated that tuberculosis would not be eliminated from the United States without a more effective vaccine. Recent scientific advances have created unprecedented opportunity for tuberculosis vaccine development. Therefore, members of the broad tuberculosis research and control communities have recently created and proposed a national strategy, or blueprint, for tuberculosis vaccine development, which is presented here.

Effective nonvaccine interventions to be considered alongside human papilloma virus vaccine delivery.

PubMed

Hindin, Michelle J; Bloem, Paul; Ferguson, Jane

2015-01-01

World Health Organization recommends that girls, ages 9-13 years, get the human papilloma virus (HPV) vaccine. Global Alliance for Vaccines Initiative, which provides low-cost vaccine to eligible countries, requires that an additional intervention to be offered alongside the vaccine. We systematically searched and assessed the published literature in lower- and middle-income countries to identify effective interventions. We conducted systematic searches of four databases: PubMed, EMBASE, Global Index Medicus Regional Databases, and Cochrane Reviews for effective adolescent health interventions that could be delivered with the HPV vaccine in the following areas: (1) iron and folic acid supplementation (iron alone or with folic acid); (2) voucher delivery and cash transfer programs; (3) hand washing and soap provision; (4) vision screening; (5) promotion of physical activity/exercise; (6) menstrual hygiene education; (7) sexual and reproductive health education; (8) human immunodeficiency virus prevention activities; and (9) condom promotion, condom use skill building, and demonstration. We found limited evidence of consistent positive impact. Iron supplementation reduced iron-deficiency anemia and raised serum ferritin levels. Promotion of physical activity lowered blood pressure and reduced weight gain. Sexual and reproductive health and human immunodeficiency virus interventions improved adolescent communication with adults but did not influence behavioral outcomes. Countries should consider locally relevant and proven interventions to be offered alongside the HPV vaccine. Copyright © 2015 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Human papillomavirus vaccine policy and delivery in Latin America and the Caribbean.

PubMed

Andrus, Jon Kim; Lewis, Merle J; Goldie, Sue J; García, Patricia J; Winkler, Jennifer L; Ruiz-Matus, Cuauhtémoc; de Quadros, Ciro A

2008-08-19

Cervical cancer caused by human papillomavirus (HPV) is a major preventable public health problem. Two vaccines are now available for primary prevention of HPV infection and their introduction offers new opportunities to enhance comprehensive cervical cancer prevention and control. Currently, HPV vaccine price is a significant barrier to rapid vaccine introduction and access. Therefore, making evidence-based decisions about whether and how to introduce HPV vaccine into the immunization schedule in the countries of Latin America and the Caribbean (LAC) requires a rigorous analysis of several factors. These include: estimates of disease burden, cost-effectiveness, operational feasibility of reaching a population of adolescent females and other key analyses that have been used in recent years to support the introduction of other vaccines, such as rotavirus and pneumococcal conjugate vaccines. Given the large number of public health priorities that are competing for limited public resources, developing and using a sound evidence base is of particular importance for vaccines, like HPV, which are currently available only at prices higher than other vaccines now in use. HPV vaccination provides the opportunity to dramatically improve women's health and partnerships must also be broad-based and effectively coordinated. This can be achieved by developing programs based on the lessons learned from vaccination strategies used to eliminate rubella and neonatal tetanus and for scaling up influenza vaccination in countries of LAC.

The state-of-the-art of approved and under-development cholera vaccines.

PubMed

Pastor, M; Pedraz, J L; Esquisabel, A

2013-08-28

Cholera remains a huge public health problem. Although in 1894, the first cholera vaccination was reported, an ideal vaccine that meets all the requirements of the WHO has not yet been produced. Among the different approaches used for cholera vaccination, attenuated vaccines represent a major category; these vaccines are beneficial in being able to induce a strong protective response after a single administration. However, they have possible negative effects on immunocompromised patient populations. Both the licensed CVD103-HgR and other vaccine approaches under development are detailed in this article, such as the Vibrio cholerae 638 vaccine candidate, Peru-15 or CholeraGarde(®) and the VA1.3, VA1.4, IEM 108 VCUSM2 and CVD 112 vaccine candidates. In another strategy, killed V. cholerae vaccines have been developed, including Dukoral(®), mORCAX(®) and Sanchol™. The killed vaccines are already sold, and they have successfully demonstrated their potential to protect populations in endemic areas or after natural disasters. However, these vaccines do not fulfill all the requirements of the WHO because they fail to confer long-term protection, are not suitable for children under two years, require more than a single dose and require a distribution chain with cold storage. Lastly, other vaccine strategies under development are summarized in this review. Among these strategies, vaccine candidates based on alternative drug delivery systems that have been reported lately in the literature are discussed, such as microparticles, proteoliposomes, LPS subunits, DNA vaccines and rice seeds containing toxin subunits. Preliminary results reported by many groups working on alternative delivery systems for cholera vaccines demonstrate the importance of new technologies in addressing old problems such as cholera. Although a fully ideal vaccine has not yet been designed, promising steps have been reported in the literature resulting in hope for the fight against cholera

Live RB51 vaccine lyophilized hydrogel formulations with increased shelf life for practical ballistic delivery

USDA-ARS?s Scientific Manuscript database

Ballistic delivery capability is essential to delivering vaccines and other therapeutics effectively to both livestock and wildlife in many global scenarios. Here, lyophilized poly(ethylene glycol) (PEG)-glycolide dimethacrylate crosslinked but degradable hydrogels were assessed as payload vehicles ...

New approaches for antigen discovery, production and delivery: vaccines for veterinary and human use.

PubMed

Potter, A A; Babiuk, L A

2001-11-01

Vaccination of individuals has been practiced for many years and has been one of the most effective methods of controlling infectious diseases. Unfortunately, even with this success, society continues to suffer multi-billion dollar economic losses annually due to infectious diseases. These losses occur in all animal species as well as in humans. In order to further reduce these losses, academicians and companies are employing the multidisciplinary approach to develop better and safer vaccines. These include capitalizing on advances in molecular biology, chemistry, pharmacy, immunology, genomics, proteomics, and fermentation. Thus, we are moving from a more empirical approach to vaccine production to a more focused, and, hopefully, more logical approach to identification and production of protective antigens. Furthermore, formulation and delivery of these antigens in playing a major role in revolutionizing how we deliver vaccines to induce the most appropriate immune response and ensure protection. The current review summarizes some of these advances and speculates as to how future vaccines will be produced and delivered for the benefit of society.

Novel Strategies for Anterior Segment Ocular Drug Delivery

PubMed Central

Cholkar, Kishore; Patel, Sulabh P.; Vadlapudi, Aswani Dutt

2013-01-01

Abstract Research advancements in pharmaceutical sciences have led to the development of new strategies in drug delivery to anterior segment. Designing a new delivery system that can efficiently target the diseased anterior ocular tissue, generate high drug levels, and maintain prolonged and effective concentrations with no or minimal side effects is the major focus of current research. Drug delivery by traditional method of administration via topical dosing is impeded by ocular static and dynamic barriers. Various products have been introduced into the market that prolong drug retention in the precorneal pocket and to improve bioavailability. However, there is a need of a delivery system that can provide controlled release to treat chronic ocular diseases with a reduced dosing frequency without causing any visual disturbances. This review provides an overview of anterior ocular barriers along with strategies to overcome these ocular barriers and deliver therapeutic agents to the affected anterior ocular tissue with a special emphasis on nanotechnology-based drug delivery approaches. PMID:23215539

A semi-synthetic whole parasite vaccine designed to protect against blood stage malaria.

PubMed

Giddam, Ashwini Kumar; Reiman, Jennifer M; Zaman, Mehfuz; Skwarczynski, Mariusz; Toth, Istvan; Good, Michael F

2016-10-15

Although attenuated malaria parasitized red blood cells (pRBCs) are promising vaccine candidates, their application in humans may be restricted for ethical and regulatory reasons. Therefore, we developed an organic microparticle-based delivery platform as a whole parasite malaria-antigen carrier to mimic pRBCs. Killed blood stage parasites were encapsulated within liposomes that are targeted to antigen presenting cells (APCs). Mannosylated lipid core peptides (MLCPs) were used as targeting ligands for the liposome-encapsulated parasite antigens. MLCP-liposomes, but not unmannosylated liposomes, were taken-up efficiently by APCs which then significantly upregulated expression of MHC-ll and costimulatory molecules, CD80 and CD86. Two such vaccines using rodent model systems were constructed - one with Plasmodium chabaudi and the other with P. yoelii. MLCP-liposome vaccines were able to control the parasite burden and extended the survival of mice. Thus, we have demonstrated an alternative delivery system to attenuated pRBCs with similar vaccine efficacy and added clinical advantages. Such liposomes are promising candidates for a human malaria vaccine. Attenuated whole parasite-based vaccines, by incorporating all parasite antigens, are very promising candidates, but issues relating to production, storage and safety concerns are significantly slowing their development. We therefore developed a semi-synthetic whole parasite malaria vaccine that is easily manufactured and stored. Two such prototype vaccines (a P. chabaudi and a P. yoelii vaccine) have been constructed. They are non-infectious, highly immunogenic and give good protection profiles. This semi-synthetic delivery platform is an exciting strategy to accelerate the development of a licensed malaria vaccine. Moreover, this strategy can be potentially applied to a wide range of pathogens. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Impact of Targeted Tuberculosis Vaccination Among a Mining Population in South Africa: A Model-Based Study.

PubMed

Shrestha, Sourya; Chihota, Violet; White, Richard G; Grant, Alison D; Churchyard, Gavin J; Dowdy, David W

2017-12-15

Optimizing the use of new tools, such as vaccines, may play a crucial role in reaching global targets for tuberculosis (TB) control. Some of the most promising candidate vaccines target adults, although high-coverage mass vaccinations may be logistically more challenging among this population than among children. Vaccine-delivery strategies that target high-risk groups or settings might yield proportionally greater impact than do those that target the general population. We developed an individual-based TB transmission model representing a hypothetical population consisting of people who worked in South African gold mines or lived in associated labor-sending communities. We simulated the implementation of a postinfection adult vaccine with 60% efficacy and a mean effect duration of 10 years. We then compared the impact of a mine-targeted vaccination strategy, in which miners were vaccinated while in the mines, with that of a community-targeted strategy, in which random individuals within the labor-sending communities were vaccinated. Mine-targeted vaccination averted an estimated 0.37 TB cases per vaccine dose compared with 0.25 for community-targeted vaccination, for a relative efficacy of 1.46 (95% range, 1.13-1.91). The added benefit of mine-targeted vaccination primarily reflected the disproportionate demographic burden of TB among the population of adult males as a whole. As novel vaccines for TB are developed, venue-based vaccine delivery that targets high-risk demographic groups may improve both vaccine feasibility and the impact on transmission. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cost-effectiveness and public health impact of alternative influenza vaccination strategies in high-risk adults.

PubMed

Raviotta, Jonathan M; Smith, Kenneth J; DePasse, Jay; Brown, Shawn T; Shim, Eunha; Nowalk, Mary Patricia; Wateska, Angela; France, Glenson S; Zimmerman, Richard K

2017-10-09

High-dose trivalent inactivated influenza vaccine (HD-IIV3) or recombinant trivalent influenza vaccine (RIV) may increase influenza vaccine effectiveness (VE) in adults with conditions that place them at high risk for influenza complications. This analysis models the public health impact and cost-effectiveness (CE) of these vaccines for 50-64year-olds. Markov model CE analysis compared 5 strategies in 50-64year-olds: no vaccination; only standard-dose IIV3 offered (SD-IIV3 only), only quadrivalent influenza vaccine offered (SD-IIV4 only); high-risk patients receiving HD-IIV3, others receiving SD-IIV3 (HD-IIV3 & SD-IIV3); and high-risk patients receiving HD-IIV3, others receiving SD-IIV4 (HD-IIV3 & SD-IIV4). In a secondary analysis, RIV replaced HD-IIV3. Parameters were obtained from U.S. databases, the medical literature and extrapolations from VE estimates. Effectiveness was measured as 3%/year discounted quality adjusted life year (QALY) losses avoided. The least expensive strategy was SD-IIV3 only, with total costs of $99.84/person. The SD-IIV4 only strategy cost an additional $0.91/person, or $37,700/QALY gained. The HD-IIV3 & SD-IIV4 strategy cost $1.06 more than SD-IIV4 only, or $71,500/QALY gained. No vaccination and HD-IIV3 & SD-IIV3 strategies were dominated. Results were sensitive to influenza incidence, vaccine cost, standard-dose VE in the entire population and high-dose VE in high-risk patients. The CE of RIV for high-risk patients was dependent on as yet unknown parameter values. Based on available data, using high-dose influenza vaccine or RIV in middle-aged, high-risk patients may be an economically favorable vaccination strategy with public health benefits. Clinical trials of these vaccines in this population may be warranted. Copyright © 2017 Elsevier Ltd. All rights reserved.

Achieving high coverage in Rwanda's national human papillomavirus vaccination programme.

PubMed

Binagwaho, Agnes; Wagner, Claire M; Gatera, Maurice; Karema, Corine; Nutt, Cameron T; Ngabo, Fidele

2012-08-01

Virtually all women who have cervical cancer are infected with the human papillomavirus (HPV). Of the 275,000 women who die from cervical cancer every year, 88% live in developing countries. Two vaccines against the HPV have been approved. However, vaccine implementation in low-income countries tends to lag behind implementation in high-income countries by 15 to 20 years. In 2011, Rwanda's Ministry of Health partnered with Merck to offer the Gardasil HPV vaccine to all girls of appropriate age. The Ministry formed a "public-private community partnership" to ensure effective and equitable delivery. Thanks to a strong national focus on health systems strengthening, more than 90% of all Rwandan infants aged 12-23 months receive all basic immunizations recommended by the World Health Organization. In 2011, Rwanda's HPV vaccination programme achieved 93.23% coverage after the first three-dose course of vaccination among girls in grade six. This was made possible through school-based vaccination and community involvement in identifying girls absent from or not enrolled in school. A nationwide sensitization campaign preceded delivery of the first dose. Through a series of innovative partnerships, Rwanda reduced the historical two-decade gap in vaccine introduction between high- and low-income countries to just five years. High coverage rates were achieved due to a delivery strategy that built on Rwanda's strong vaccination system and human resources framework. Following the GAVI Alliance's decision to begin financing HPV vaccination, Rwanda's example should motivate other countries to explore universal HPV vaccine coverage, although implementation must be tailored to the local context.

Educating on professional habits: attitudes of medical students towards diverse strategies for promoting influenza vaccination and factors associated with the intention to get vaccinated

PubMed Central

2013-01-01

Background Influenza vaccination coverage in medical students is usually low. Unlike health care workers, there is little information on the attitudes to and predictors of vaccination among medical students, and their attitudes towards institutional strategies for improving rates are unknown. Methods This cross-sectional study evaluated the effect of three influenza vaccination promotional strategies (Web page, video and tri-fold brochure) on medical students’ intention to get vaccinated and associated factors. A total of 538 medical students were asked to answer an anonymous questionnaire assessing the intention to get vaccinated after exposure to any of the promotional strategies. Sociodemographic data collected included: sex, age, university year, influenza risk group and cohabiting with member of a risk group. Results Four hundred twenty-one students answered the questionnaire, of whom 312 (74.1%) were female, 113 (26.8%) had done clinical rotations, and 111 (26.6%) reported intention to get the flu shot. Logistic regression showed the web group had a greater intention to get vaccinated than the reference group (OR: 2.42 95% CI: 1.16-5.03). Having done clinical rotations (OR: 2.55 95% CI: 1.36-4.38) and having received the shot in previous flu seasons (OR: 13.69 95% CI: 7.86-23.96) were independently associated with the intention to get vaccinated. Conclusion Given that previous vaccination is a factor associated with the intention to get vaccinated, education on vaccination of health care workers should begin while they are students, thereby potentiating the habit. In addition, the intention to get vaccinated was greater during the clinical phase of the university career, suggesting this is a good time to introduce promotion strategies. Online promotional campaigns, such as a thematic Web to promote vaccination of health workers, could improve the intention to get vaccinated. PMID:23866902

Contagious bovine pleuropneumonia vaccines and control strategies: recent data.

PubMed

Thiaucourt, F; Aboubakar, Y; Wesonga, H; Manso-Silvan, L; Blanchard, A

2004-01-01

Contagious bovine pleuropneumonia is one of the most threatening transboundary cattle disease in Africa. However, with the exception of Botswana, very few African countries were able to implement eradication strategies for this disease, after it had recently re-infected a number of countries. Previous experimental studies have shown that emergency vaccination campaigns, based on a single injection, were not inducing a sufficient protection level to prevent further spread of the disease. In addition, post-vaccinal reactions were sometimes reported in the field when using vaccine strain T1/44, leading cattle owners to refuse the vaccination. On the contrary, antibiotics are used quite often in the field but there are insufficient data to assess their efficacy properly. Therefore experimental studies were implemented: (i) to check if higher dosages of the vaccine would be able to induce higher protection rates and (ii) to elucidate the origin of the post-vaccinal reactions observed with T1/44 and (iii) to gain preliminary results on the efficacy of long-acting tetracycline. The first experiment included the use of three doses of vaccine strains T1/44 and T1sr: 10(7), 10(8) and 10(9) mycoplasmas per dose. T1/44 seemed to induce a higher protection (70%) than T1sr (60%). However, there was no observable dose effect for these vaccine strains. The second experiment was performed by injecting various MmmSC strains subcutaneously into susceptible cattle. One of these strains was an isolate obtained from a "Willems" reaction following a vaccination with T1/44. This isolate, called T1B, induced typical invading oedema at the injection site in a similar way to the pathogenic strain, whereas the original T1/44 vaccine strain did not. These findings indicate that the strain has reverted to virulence. Finally the antibiotic trials showed that long-acting tetracycline was able to reduce the losses due to the disease but could not prevent the persistence of viable MmmSC in treated

Novel approaches to vaginal delivery and safety of microbicides: biopharmaceuticals, nanoparticles, and vaccines.

PubMed

Whaley, Kevin J; Hanes, Justin; Shattock, Robin; Cone, Richard A; Friend, David R

2010-12-01

The HIV-1 epidemic remains unchecked despite existing technology; vaccines and microbicides in development may help reverse the epidemic. Reverse transcriptase inhibitors (RTIs) formulated in gels tenofovir (TFV) and IVRs (dapivirine) are under clinical development. While TFV or similar products may prove successful for HIV-1, alternatives to RTIs may provide additional benefits, e.g., broader STI prevention. Biopharmaceutical agents under development as microbicides include cyanovirin, RANTES analogues, commensals, and Mabs. Cost of manufacturing biopharmaceuticals has been reduced and they can be formulated into tablets, films, and IVRs for vaginal delivery. Nanotechnology offers a novel approach to formulate microbicides potentially leading to uniform epithelial delivery. Delivery through vaginal mucus may be possible by controlling nanoparticle size and surface characteristics. Combining prevention modalities may be the most effective means of preventing STI transmission, importantly, codelivery of microbicides and vaccines has demonstrated. Finally, the safety of microbicide preparations and excipients commonly used can be assessed using a mouse/HSV-2 susceptibility model. Screening of new microbicide candidates and formulation excipients may avoid past issues of enhancing HIV-1 transmission. This article forms part of a special supplement covering several presentations on novel microbicide formulations from the symposium on "Recent Trends in Microbicide Formulations" held on 25 and 26 January 2010, Arlington, VA. Copyright © 2010 Elsevier B.V. All rights reserved.

European union regulatory developments for new vaccine adjuvants and delivery systems.

PubMed

Sesardic, Dorothea; Dobbelaer, Roland

2004-06-23

Interest in vaccine adjuvants and new delivery systems has grown rapidly over the past few years. New vaccine candidates have emerged, which, because of their poor immunogenicity, rely on adjuvants to improve their presentation and targeting and to potentiate their protective immune response. Better understandings of the mechanisms of action, together with logistic and economical considerations have resulted in an explosion of technologies. However, there have been few new registered products for human use, and antigens incorporated into immunostimulating reconstituted influenza virosomes have only relatively recently been licensed in European Union (EU) countries. Influenza vaccine, adjuvanted with water in oil emulsion containing squalene (adjuvant MF59C1) is now also approved. Although current EU regulations focus on traditional adjuvants, notably aluminium and calcium salts, advances have been made in regulatory considerations. The European agency for the evaluation of medicinal products, through its working parties, is actively drafting guidance on requirements for the evaluation of new adjuvants in vaccines. This paper summarises the new developments in EU regulatory aspects relevant to adjuvant quality at development stages, during the manufacturing process, and at the final bulk stage of adjuvant with antigen, and also summarises regulatory expectation regarding safety at pre-clinical and clinical stages. The paper highlights the regulatory concerns and existing bottlenecks that have led to slow approval of new technologies.

Antigen-displaying lipid-enveloped PLGA nanoparticles as delivery agents for a Plasmodium vivax malaria vaccine.

PubMed

Moon, James J; Suh, Heikyung; Polhemus, Mark E; Ockenhouse, Christian F; Yadava, Anjali; Irvine, Darrell J

2012-01-01

The parasite Plasmodium vivax is the most frequent cause of malaria outside of sub-Saharan Africa, but efforts to develop viable vaccines against P. vivax so far have been inadequate. We recently developed pathogen-mimicking polymeric vaccine nanoparticles composed of the FDA-approved biodegradable polymer poly(lactide-co-glycolide) acid (PLGA) "enveloped" by a lipid membrane. In this study, we sought to determine whether this vaccine delivery platform could be applied to enhance the immune response against P. vivax sporozoites. A candidate malaria antigen, VMP001, was conjugated to the lipid membrane of the particles, and an immunostimulatory molecule, monophosphoryl lipid A (MPLA), was incorporated into the lipid membranes, creating pathogen-mimicking nanoparticle vaccines (VMP001-NPs). Vaccination with VMP001-NPs promoted germinal center formation and elicited durable antigen-specific antibodies with significantly higher titers and more balanced Th1/Th2 responses in vivo, compared with vaccines composed of soluble protein mixed with MPLA. Antibodies raised by NP vaccinations also exhibited enhanced avidity and affinity toward the domains within the circumsporozoite protein implicated in protection and were able to agglutinate live P. vivax sporozoites. These results demonstrate that these VMP001-NPs are promising vaccines candidates that may elicit protective immunity against P. vivax sporozoites.

Lipid based delivery and immuno-stimulatory systems: Master tools to combat leishmaniasis.

PubMed

Sabur, Abdus; Asad, Mohammad; Ali, Nahid

2016-11-01

Disease management of leishmaniasis is appalling due to lack of a human vaccine and the toxicity and resistance concerns with limited therapeutic drugs. The challenges in development of a safe vaccine for generation and maintenance of robust antileishmanial protective immunity through a human administrable route of immunization can be addressed through immunomodulation and targeted delivery. The versatility of lipid based particulate system for deliberate delivery of diverse range of molecules including immunomodulators, antigens and drugs have essentially found pivotal role in design of proficient vaccination and therapeutic strategies against leishmaniasis. The prospects of lipid based preventive and curative formulations for leishmaniasis have been highlighted in this review. Copyright © 2016. Published by Elsevier Inc.

Using quality improvement methods to increase use of pain prevention strategies for childhood vaccination.

PubMed

Schurman, Jennifer Verrill; Deacy, Amanda D; Johnson, Rebecca J; Parker, Jolynn; Williams, Kristi; Wallace, Dustin; Connelly, Mark; Anson, Lynn; Mroczka, Kevin

2017-02-08

To increase evidence-based pain prevention strategy use during routine vaccinations in a pediatric primary care clinic using quality improvement methodology. Specific intervention strategies ( i.e ., comfort positioning, nonnutritive sucking and sucrose analgesia, distraction) were identified, selected and introduced in three waves, using a Plan-Do-Study-Act framework. System-wide change was measured from baseline to post-intervention by: (1) percent of vaccination visits during which an evidence-based pain prevention strategy was reported as being used; and (2) caregiver satisfaction ratings following the visit. Additionally, self-reported staff and caregiver attitudes and beliefs about pain prevention were measured at baseline and 1-year post-intervention to assess for possible long-term cultural shifts. Significant improvements were noted post-intervention. Use of at least one pain prevention strategy was documented at 99% of patient visits and 94% of caregivers were satisfied or very satisfied with the pain prevention care received. Parents/caregivers reported greater satisfaction with the specific pain prevention strategy used [ t (143) = 2.50, P ≤ 0.05], as well as greater agreement that the pain prevention strategies used helped their children's pain [ t (180) = 2.17, P ≤ 0.05] and that they would be willing to use the same strategy again in the future [ t (179) = 3.26, P ≤ 0.001] as compared to baseline. Staff and caregivers also demonstrated a shift in attitudes from baseline to 1-year post-intervention. Specifically, staff reported greater agreement that the pain felt from vaccinations can result in harmful effects [2.47 vs 3.10; t (70) = -2.11, P ≤ 0.05], less agreement that pain from vaccinations is "just part of the process" [3.94 vs 3.23; t (70) = 2.61, P ≤ 0.05], and less agreement that parents expect their children to experience pain during vaccinations [4.81 vs 4.38; t (69) = 2.24, P ≤ 0.05]. Parents/caregivers reported more favorable

Schistosomiasis elimination strategies and potential role of a vaccine in achieving global health goals.

PubMed

Mo, Annie X; Agosti, Jan M; Walson, Judd L; Hall, B Fenton; Gordon, Lance

2014-01-01

In March 2013, the National Institute of Allergy and Infectious Diseases and the Bill and Melinda Gates Foundation co-sponsored a meeting entitled "Schistosomiasis Elimination Strategy and Potential Role of a Vaccine in Achieving Global Health Goals" to discuss the potential role of schistosomiasis vaccines and other tools in the context of schistosomiasis control and elimination strategies. It was concluded that although schistosomiasis elimination in some focal areas may be achievable through current mass drug administration programs, global control and elimination will face several significant scientific and operational challenges, and will require an integrated approach with other, additional interventions. These challenges include vector (snail) control; environmental modification; water, sanitation, and hygiene; and other future innovative tools such as vaccines. Defining a clear product development plan that reflects a vaccine strategy as complementary to the existing control programs to combat different forms of schistosomiasis will be important to develop a vaccine effectively.

Dengue Fever: Causes, Complications, and Vaccine Strategies

PubMed Central

Khanna, Ira

2016-01-01

Dengue is a highly endemic infectious disease of the tropical countries and is rapidly becoming a global burden. It is caused by any of the 4 serotypes of dengue virus and is transmitted within humans through female Aedes mosquitoes. Dengue disease varies from mild fever to severe conditions of dengue hemorrhagic fever and shock syndrome. Globalization, increased air travel, and unplanned urbanization have led to increase in the rate of infection and helped dengue to expand its geographic and demographic distribution. Dengue vaccine development has been a challenging task due to the existence of four antigenically distinct dengue virus serotypes, each capable of eliciting cross-reactive and disease-enhancing antibody response against the remaining three serotypes. Recently, Sanofi Pasteur's chimeric live-attenuated dengue vaccine candidate has been approved in Mexico, Brazil, and Philippines for usage in adults between 9 and 45 years of age. The impact of its limited application to the public health system needs to be evaluated. Simultaneously, the restricted application of this vaccine candidate warrants continued efforts in developing a dengue vaccine candidate which is additionally efficacious for infants and naïve individuals. In this context, alternative strategies of developing a designed vaccine candidate which does not allow production of enhancing antibodies should be explored, as it may expand the umbrella of efficacy to include infants and naïve individuals. PMID:27525287

Future vaccination strategies against tuberculosis: thinking outside the box.

PubMed

Kaufmann, Stefan H E

2010-10-29

With almost a dozen vaccine candidates in clinical trials, tuberculosis (TB) research and development is finally reaping the first fruits of its labors. Vaccine candidates in clinical trials may prevent TB disease reactivation by efficiently containing the pathogen Mycobacterium tuberculosis (Mtb). Future research should target vaccines that achieve sterile eradication of Mtb or even prevent stable infection. These are ambitious goals that can be reached only by highly cooperative engagement of basic immunologists, vaccinologists, and clinical researchers--or in other words, by translation from basic immunology to vaccine research and development, as well as reverse translation of insights from clinical trials back to hypothesis-driven research in the basic laboratory. Here, we review current and future strategies toward the rational design of novel vaccines against TB, as well as the progress made thus far, and the hurdles that need to be overcome in the near and distant future. Copyright © 2010 Elsevier Inc. All rights reserved.

Newcastle disease virus vectored vaccines as bivalent or antigen delivery vaccines

PubMed Central

2017-01-01

Recent advances in reverse genetics techniques make it possible to manipulate the genome of RNA viruses such as Newcastle disease virus (NDV). Several NDV vaccine strains have been used as vaccine vectors in poultry, mammals, and humans to express antigens of different pathogens. The safety, immunogenicity, and protective efficacy of these NDV-vectored vaccines have been evaluated in pre-clinical and clinical studies. The vaccines are safe in mammals, humans, and poultry. Bivalent NDV-vectored vaccines against pathogens of economic importance to the poultry industry have been developed. These bivalent vaccines confer solid protective immunity against NDV and other foreign antigens. In most cases, NDV-vectored vaccines induce strong local and systemic immune responses against the target foreign antigen. This review summarizes the development of NDV-vectored vaccines and their potential use as a base for designing other effective vaccines for veterinary and human use. PMID:28775971

Novel freeze-dried DDA and TPGS liposomes are suitable for nasal delivery of vaccine.

PubMed

Yusuf, Helmy; Ali, Ahlam A; Orr, Natalie; Tunney, Michael M; McCarthy, Helen O; Kett, Vicky L

2017-11-25

There is a pressing need for effective needle-free vaccines that are stable enough for use in the developing world and stockpiling. The inclusion of the cationic lipid DDA and the PEG-containing moiety TPGS into liposomes has the potential to improve mucosal delivery. The aim of this study was to develop stable lyophilized cationic liposomes based on these materials suitable for nasal antigen delivery. Liposomes containing DDA and TPGS were developed. Size and zeta potential measurements, ex vivo, CLSM cell penetration study and cell viability investigations were made. Preliminary immunisation and stability studies using ovalbumin were performed. The liposomes exhibited suitable size and charge for permeation across nasal mucosa. DDA and TPGS increased tissue permeation in ex vivo studies and cell uptake with good cell viability. The liposomes improved immune response both locally and vaginally when compared to i.m administration or control liposomes delivered nasally. Additionally, the lyophilized products demonstrated good stability in terms of Tg, size and antigen retention. This study has shown that the novel liposomes have potential for development as a mucosal vaccine delivery system. Furthermore, the stability of the lyophilized liposomes offers potential additional benefits in terms of thermal stability over liquid formats. Copyright © 2017 Elsevier B.V. All rights reserved.

Gene Delivery Strategies to Promote Spinal Cord Repair

PubMed Central

Walthers, Christopher M; Seidlits, Stephanie K

2015-01-01

Gene therapies hold great promise for the treatment of many neurodegenerative disorders and traumatic injuries in the central nervous system. However, development of effective methods to deliver such therapies in a controlled manner to the spinal cord is a necessity for their translation to the clinic. Although essential progress has been made to improve efficiency of transgene delivery and reduce the immunogenicity of genetic vectors, there is still much work to be done to achieve clinical strategies capable of reversing neurodegeneration and mediating tissue regeneration. In particular, strategies to achieve localized, robust expression of therapeutic transgenes by target cell types, at controlled levels over defined time periods, will be necessary to fully regenerate functional spinal cord tissues. This review summarizes the progress over the last decade toward the development of effective gene therapies in the spinal cord, including identification of appropriate target genes, improvements to design of genetic vectors, advances in delivery methods, and strategies for delivery of multiple transgenes with synergistic actions. The potential of biomaterials to mediate gene delivery while simultaneously providing inductive scaffolding to facilitate tissue regeneration is also discussed. PMID:25922572

Induction of CD8(+) T cell responses and protective efficacy following microneedle-mediated delivery of a live adenovirus-vectored malaria vaccine.

PubMed

Pearson, Frances E; O'Mahony, Conor; Moore, Anne C; Hill, Adrian V S

2015-06-22

There is an urgent need for improvements in vaccine delivery technologies. This is particularly pertinent for vaccination programmes within regions of limited resources, such as those required for adequate provision for disposal of used needles. Microneedles are micron-sized structures that penetrate the stratum corneum of the skin, creating temporary conduits for the needle-free delivery of drugs or vaccines. Here, we aimed to investigate immunity induced by the recombinant simian adenovirus-vectored vaccine ChAd63.ME-TRAP; currently undergoing clinical assessment as a candidate malaria vaccine, when delivered percutaneously by silicon microneedle arrays. In mice, we demonstrate that microneedle-mediated delivery of ChAd63.ME-TRAP induced similar numbers of transgene-specific CD8(+) T cells compared to intradermal (ID) administration with needle-and-syringe, following a single immunisation and after a ChAd63/MVA heterologous prime-boost schedule. When mice immunised with ChAd63/MVA were challenged with live Plasmodium berghei sporozoites, microneedle-mediated ChAd63.ME-TRAP priming demonstrated equivalent protective efficacy as did ID immunisation. Furthermore, responses following ChAd63/MVA immunisation correlated with a specific design parameter of the array used ('total array volume'). The level of transgene expression at the immunisation site and skin-draining lymph node (dLN) was also linked to total array volume. These findings have implications for defining silicon microneedle array design for use with live, vectored vaccines. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biodegradable nanoparticle delivery of inactivated swine influenza virus vaccine provides heterologous cell-mediated immune response in pigs.

PubMed

Dhakal, Santosh; Hiremath, Jagadish; Bondra, Kathryn; Lakshmanappa, Yashavanth S; Shyu, Duan-Liang; Ouyang, Kang; Kang, Kyung-Il; Binjawadagi, Basavaraj; Goodman, Jonathan; Tabynov, Kairat; Krakowka, Steven; Narasimhan, Balaji; Lee, Chang Won; Renukaradhya, Gourapura J

2017-02-10

Swine influenza virus (SwIV) is one of the important zoonotic pathogens. Current flu vaccines have failed to provide cross-protection against evolving viruses in the field. Poly(lactic-co-glycolic acid) (PLGA) is a biodegradable FDA approved polymer and widely used in drug and vaccine delivery. In this study, inactivated SwIV H1N2 antigens (KAg) encapsulated in PLGA nanoparticles (PLGA-KAg) were prepared, which were spherical in shape with 200 to 300nm diameter, and induced maturation of antigen presenting cells in vitro. Pigs vaccinated twice with PLGA-KAg via intranasal route showed increased antigen specific lymphocyte proliferation and enhanced the frequency of T-helper/memory and cytotoxic T cells (CTLs) in peripheral blood mononuclear cells (PBMCs). In PLGA-KAg vaccinated and heterologous SwIV H1N1 challenged pigs, clinical flu symptoms were absent, while the control pigs had fever for four days. Grossly and microscopically, reduced lung pathology and viral antigenic mass in the lung sections with clearance of infectious challenge virus in most of the PLGA-KAg vaccinated pig lung airways were observed. Immunologically, PLGA-KAg vaccine irrespective of not significantly boosting the mucosal antibody response, it augmented the frequency of IFN-γ secreting total T cells, T-helper and CTLs against both H1N2 and H1N1 SwIV. In summary, inactivated influenza virus delivered through PLGA-NPs reduced the clinical disease and induced cross-protective cell-mediated immune response in a pig model. Our data confirmed the utility of a pig model for intranasal particulate flu vaccine delivery platform to control flu in humans. Copyright © 2017 Elsevier B.V. All rights reserved.

Challenges in immunisation service delivery for refugees in Australia: A health system perspective.

PubMed

Mahimbo, A; Seale, H; Smith, M; Heywood, A

2017-09-12

Refugees are at risk of being under-immunised in their countries of origin, in transit and post-resettlement in Australia. Whilst studies have focused on identifying barriers to accessibility of health services among refugees, few focus on providers' perspectives on immunisation service delivery to this group. Health service providers are well placed to provide insights into the pragmatic challenges associated with refugee health service delivery, which can be useful in identifying strategies aimed at improving immunisation coverage among this group. A qualitative study involving 30 semi-structured interviews was undertaken with key stakeholders in immunisation service delivery across all States and Territories in Australia between December 2014 and December 2015. Thematic analysis was undertaken. Variability in accessing program funding and vaccines, lack of a national policy for catch-up vaccination, unclear roles and responsibilities for catch-up, a lack of a central immunisation register and insufficient training among general practitioners were seen as the main challenges impacting on immunisation service delivery for refugees. This study provides insight into the challenges that impact on effective immunisation service delivery for refugees. Deliberate strategies such as national funding for relevant vaccines, improved data collection nationally and increased guidance for general practitioners on catch-up immunisation for refugees would help to ensure equitable access across all age groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

Clinical evaluation of a novel microneedle device for intradermal delivery of an influenza vaccine: are all delivery methods the same?

PubMed

Levin, Yotam; Kochba, Efrat; Kenney, Richard

2014-07-23

The skin provides the largest immune barrier to infection and is a readily accessible site for vaccination, although intradermal (ID) injection can be challenging. The MicronJet™ microneedle is a novel device that consistently injects antigens very close to the skin's dendritic cells. A dose-sparing ID injection study was conducted in 280 healthy adult volunteers using trivalent virosomal adjuvanted influenza vaccine. ID injection of 3 μg using the MicronJet™ was well tolerated and showed a statistically higher geometric mean fold rise than the same dose ID using a conventional needle (Mantoux technique) for the H1N1 and B strains or a 15 μg intramuscular (IM) injection for the H3N2 strain. Thus, the immune response appears to partially depend on the delivery device and route of injection. The MicronJet™ may allow dose-sparing, yet give a superior response in influenza vaccination and warrants further clinical evaluation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Lessons learnt from human papillomavirus (HPV) vaccination in 45 low- and middle-income countries

PubMed Central

Howard, Natasha; Kabakama, Severin; Mounier-Jack, Sandra; Griffiths, Ulla K.; Feletto, Marta; Burchett, Helen E. D.; LaMontagne, D. Scott; Watson-Jones, Deborah

2017-01-01

Objective To synthesise lessons learnt and determinants of success from human papillomavirus (HPV) vaccine demonstration projects and national programmes in low- and middle-income countries (LAMICs). Methods Interviews were conducted with 56 key informants. A systematic literature review identified 2936 abstracts from five databases; after screening 61 full texts were included. Unpublished literature, including evaluation reports, was solicited from country representatives; 188 documents were received. A data extraction tool and interview topic guide outlining key areas of inquiry were informed by World Health Organization guidelines for new vaccine introduction. Results were synthesised thematically. Results Data were analysed from 12 national programmes and 66 demonstration projects in 46 countries. Among demonstration projects, 30 were supported by the GARDASIL® Access Program, 20 by Gavi, four by PATH and 12 by other means. School-based vaccine delivery supplemented with health facility-based delivery for out-of-school girls attained high coverage. There were limited data on facility-only strategies and little evaluation of strategies to reach out-of-school girls. Early engagement of teachers as partners in social mobilisation, consent, vaccination day coordination, follow-up of non-completers and adverse events was considered invaluable. Micro-planning using school/ facility registers most effectively enumerated target populations; other estimates proved inaccurate, leading to vaccine under- or over-estimation. Refresher training on adverse events and safe injection procedures was usually necessary. Conclusion Considerable experience in HPV vaccine delivery in LAMICs is available. Lessons are generally consistent across countries and dissemination of these could improve HPV vaccine introduction. PMID:28575074

[Use the Markov-decision tree model to optimize vaccination strategies of hepatitis E among women aged 15 to 49].

PubMed

Chen, Z M; Ji, S B; Shi, X L; Zhao, Y Y; Zhang, X F; Jin, H

2017-02-10

Objective: To evaluate the cost-utility of different hepatitis E vaccination strategies in women aged 15 to 49. Methods: The Markov-decision tree model was constructed to evaluate the cost-utility of three hepatitis E virus vaccination strategies. Parameters of the models were estimated on the basis of published studies and experience of experts. Both methods on sensitivity and threshold analysis were used to evaluate the uncertainties of the model. Results: Compared with non-vaccination group, strategy on post-screening vaccination with rate as 100%, could save 0.10 quality-adjusted life years per capital in the women from the societal perspectives. After implementation of screening program and with the vaccination rate reaching 100%, the incremental cost utility ratio (ICUR) of vaccination appeared as 5 651.89 and 6 385.33 Yuan/QALY, respectively. Vaccination post to the implementation of a screening program, the result showed better benefit than the vaccination rate of 100%. Results from the sensitivity analysis showed that both the cost of hepatitis E vaccine and the inoculation compliance rate presented significant effects. If the cost were lower than 191.56 Yuan (RMB) or the inoculation compliance rate lower than 0.23, the vaccination rate of 100% strategy was better than the post-screening vaccination strategy, otherwise the post-screening vaccination strategy appeared the optimal strategy. Conclusion: Post-screening vaccination for women aged 15 to 49 from social perspectives seemed the optimal one but it had to depend on the change of vaccine cost and the rate of inoculation compliance.

Possible global strategies for stopping polio vaccination and how they could be harmonized.

PubMed

Cochi, S L; Sutter, R W; Aylward, R B

2001-01-01

One of the challenges of the polio eradication initiative over the next few years will be the formulation of an optimal strategy for stopping poliovirus vaccination after global certification of polio eradication has been accomplished. This strategy must maximize the benefits and minimize the risks. A number of strategies are currently under consideration, including: (i) synchronized global discontinuation of use of oral poliovirus vaccine (OPV); (ii) regional or subregional coordinated OPV discontinuation; and (iii) moving from trivalent to bivalent or monovalent OPV. Other options include moving from OPV to global use of IPV for an interim period before cessation of IPV use (to eliminate circulation of vaccine-derived poliovirus, if necessary) or development of new OPV strains that are not transmissible. Each of these strategies is associated with specific advantages (financial benefits for OPV discontinuation) and disadvantages (cost of switch to IPV) and inherent uncertainties (risk of continued poliovirus circulation in certain populations or prolonged virus replication in immunodeficient persons). An ambitious research agenda addresses the remaining questions and issues. Nevertheless, several generalities are already clear. Unprecedented collaboration between countries, regions, and indeed the entire world will be required to implement a global OPV discontinuation strategy Regulatory approval will be needed for an interim bivalent OPV or for monovalent OPV in many countries. Manufacturers will need sufficient lead time to produce sufficient quantities of IPV Finally, the financial implications for any of these strategies need to be considered. Whatever strategy is followed it will be necessary to stockpile supplies of a poliovirus-containing vaccine (most probably all three types of monovalent OPV), and to develop contingency plans to respond should an outbreak of polio occur after stopping vaccination.

Schistosomiasis Elimination Strategies and Potential Role of a Vaccine in Achieving Global Health Goals

PubMed Central

Mo, Annie X.; Agosti, Jan M.; Walson, Judd L.; Hall, B. Fenton; Gordon, Lance

2014-01-01

In March 2013, the National Institute of Allergy and Infectious Diseases and the Bill and Melinda Gates Foundation co-sponsored a meeting entitled “Schistosomiasis Elimination Strategy and Potential Role of a Vaccine in Achieving Global Health Goals” to discuss the potential role of schistosomiasis vaccines and other tools in the context of schistosomiasis control and elimination strategies. It was concluded that although schistosomiasis elimination in some focal areas may be achievable through current mass drug administration programs, global control and elimination will face several significant scientific and operational challenges, and will require an integrated approach with other, additional interventions. These challenges include vector (snail) control; environmental modification; water, sanitation, and hygiene; and other future innovative tools such as vaccines. Defining a clear product development plan that reflects a vaccine strategy as complementary to the existing control programs to combat different forms of schistosomiasis will be important to develop a vaccine effectively. PMID:24402703

Current and future vaccines and vaccination strategies against infectious laryngotracheitis (ILT) respiratory disease of poultry.

PubMed

García, Maricarmen

2017-07-01

Infectious laryngotracheitis (ILT) is an economically important respiratory disease of poultry that affects the industry worldwide. Vaccination is the principal tool in the control of the disease. Two types of vaccines, live attenuated and recombinant viral vector, are commercially available. The first generation of GaHV-1 vaccines available since the early 1960's are live viruses, attenuated by continuous passages in cell culture or embryos. These vaccines significantly reduce mortalities and, in particular, the chicken embryo origin (CEO) vaccines have shown to limit outbreaks of the disease. However, the CEO vaccines can regain virulence and become the source of outbreaks. Recombinant viral vector vaccines, the second generation of GaHV-1 vaccines, were first introduced in the early 2000's. These are Fowl Pox virus (FPV) and Herpes virus of turkeys (HVT) vectors expressing one or multiple GaHV-1 immunogenic proteins. Recombinant viral vector vaccines are considered a much safer alternative because they do not regain virulence. In the face of challenge, they improve bird performance and ameliorate clinical signs of the disease but fail to reduce shedding of the challenge virus increasing the likelihood of outbreaks. At the moment, several new strategies are being evaluated to improve both live attenuated and viral vector vaccines. Potential new live vaccines attenuated by deletion of genes associated with virulence or by selection of CEO viral subpopulations that do not exhibit increased virulence upon passages in birds are being evaluated. Also new vector alternatives to express GaHV-1 glycoproteins in Newcastle diseases virus (NDV) or in modified very virulent (vv) serotype I Marek's disease virus (MDV) were developed and evaluated. Copyright © 2016 Elsevier B.V. All rights reserved.

Gold nanocluster-based vaccines for dual-delivery of antigens and immunostimulatory oligonucleotides

NASA Astrophysics Data System (ADS)

Tao, Yu; Zhang, Yan; Ju, Enguo; Ren, Hui; Ren, Jinsong

2015-07-01

We here report a facile one-pot synthesis of fluorescent gold nanoclusters (AuNCs) via the peptide biomineralization method, which can elicit specific immunological responses. The as-prepared peptide-protected AuNCs (peptide-AuNCs) display strong red fluorescence, and more importantly, as compared to the peptide alone, the immune stimulatory ability of the resulting peptide-AuNCs can not only be retained, but can also be efficaciously enhanced. Moreover, through a dual-delivery of antigen peptides and cytosine-phosphate-guanine (CpG) oligodeoxynucleotides (ODNs), the as-prepared peptide-AuNC-CpG conjugates can also act as smart self-vaccines to assist in the generation of high immunostimulatory activity, and be applied as a probe for intracellular imaging. Both in vitro and in vivo studies provide strong evidence that the AuNC-based vaccines may be utilized as safe and efficient immunostimulatory agents that are able to prevent and/or treat a variety of ailments.We here report a facile one-pot synthesis of fluorescent gold nanoclusters (AuNCs) via the peptide biomineralization method, which can elicit specific immunological responses. The as-prepared peptide-protected AuNCs (peptide-AuNCs) display strong red fluorescence, and more importantly, as compared to the peptide alone, the immune stimulatory ability of the resulting peptide-AuNCs can not only be retained, but can also be efficaciously enhanced. Moreover, through a dual-delivery of antigen peptides and cytosine-phosphate-guanine (CpG) oligodeoxynucleotides (ODNs), the as-prepared peptide-AuNC-CpG conjugates can also act as smart self-vaccines to assist in the generation of high immunostimulatory activity, and be applied as a probe for intracellular imaging. Both in vitro and in vivo studies provide strong evidence that the AuNC-based vaccines may be utilized as safe and efficient immunostimulatory agents that are able to prevent and/or treat a variety of ailments. Electronic supplementary information (ESI

Antigen discovery and delivery of subunit vaccines by nonliving bacterial ghost vectors.

PubMed

Walcher, Petra; Mayr, Ulrike B; Azimpour-Tabrizi, Chakameh; Eko, Francis O; Jechlinger, Wolfgang; Mayrhofer, Peter; Alefantis, Tim; Mujer, Cesar V; DelVecchio, Vito G; Lubitz, Werner

2004-12-01

The bacterial ghost (BG) platform system is a novel vaccine delivery system endowed with intrinsic adjuvant properties. BGs are nonliving Gram-negative bacterial cell envelopes which are devoid of their cytoplasmic contents, yet maintain their cellular morphology and antigenic structures, including bioadhesive properties. The main advantages of BGs as carriers of subunit vaccines include their ability to stimulate a high immune response and to target the carrier itself to primary antigen-presenting cells. The intrinsic adjuvant properties of BGs enhance the immune response to target antigens, including T-cell activation and mucosal immunity. Since native and foreign antigens can be carried in the envelope complex of BGs, combination vaccines with multiple antigens of diverse origin can be presented to the immune system simultaneously. Beside the capacity of BGs to function as carriers of protein antigens, they also have a high loading capacity for DNA. Thus, loading BGs with recombinant DNA takes advantage of the excellent bioavailability for DNA-based vaccines and the high expression rates of the DNA-encoded antigens in target cell types such as macrophages and dendritic cells. There are many spaces within BGs including the inner and outer membranes, the periplasmic space and the internal lumen which can carry antigens, DNA or mediators of the immune response. All can be used for subunit antigen to design new vaccine candidates with particle presentation technology. In addition, the fact that BGs can also carry piggyback large-size foreign antigen particles, increases the technologic usefulness of BGs as combination vaccines against viral and bacterial pathogens. Furthermore, the BG antigen carriers can be stored as freeze-dried preparations at room temperature for extended periods without loss of efficacy. The potency, safety and relatively low production cost of BGs offer a significant technical advantage over currently utilized vaccine technologies.

Vaccination Strategies: a comparative study in an epidemic scenario

NASA Astrophysics Data System (ADS)

Prates, D. B.; Jardim, C. L. T. F.; Ferreira, L. A. F.; da Silva, J. M.; Kritz, M. V.

2016-08-01

Epidemics are an extremely important matter of study within the Mathematical Modeling area and can be widely found in the literature. Some epidemiological models use differential equations, which are very sensible to parameters, to represent and describe the diseases mathematically. For this work, a variation of the SIR model is discussed and applied to a certain epidemic scenario, wherein vaccination is introduced through two different strategies: constant vaccination and vaccination in pulses. Other epidemiological and population aspects are also considered, such as mortality/natality and infection rates. The analysis and results are performed through numerical solutions of the model and a special attention is given to the discussion generated by the paramenters variation.

A multi-country study of dengue vaccination strategies with Dengvaxia and a future vaccine candidate in three dengue-endemic countries: Vietnam, Thailand, and Colombia.

PubMed

Lee, Jung-Seok; Lourenço, José; Gupta, Sunetra; Farlow, Andrew

2018-04-19

The dengue vaccination era began when Dengvaxia (CYD-TDV) became available in 2016. In addition, several second-generation vaccine candidates are currently in phase 3 trials, suggesting that a broader availability of dengue vaccines may be possible in the near future. Advancing on the recent WHO-SAGE recommendations for the safe and effective use of CYD-TDV at the regional level on average, this study investigates the vaccination impacts and cost-effectiveness of CYD-TDV and of a hypothetical new vaccine candidate (NVC) in a country-specific manner for three endemic countries: Vietnam, Thailand, and Colombia. The vaccination impacts of CYD-TDV and NVC were derived by fitting the empirical seroprevalence rates of 9 year olds into an individual-based meta-population transmission model, previously used for the WHO-SAGE working group. The disability-adjusted life years were estimated by applying country-specific parametric values. The cost-effectiveness analyses of four intervention strategies in combination with routine and catch-up campaigns were compared for both vaccines to inform decision makers regarding the most suitable immunization program in each of the three countries. Both CYD-TDV and NVC could be cost-effective at the DALY threshold cost of $2000 depending upon vaccination costs. With CYD-TDV, targeting 9 year olds in routine vaccination programs and 10-29 year olds as a one-off catch-up campaign was the most cost-effective strategy in all three countries. With NVC, while the most cost-effective strategy was to vaccinate 9-29 and 9-18 year olds in Vietnam and Thailand respectively, vaccinating younger age cohorts between 1 and 5 years old in Colombia was more cost-effective than other strategies. Given that three countries will soon face decisions regarding whether and how to incorporate CYD-TDV or future dengue vaccines into their budget-constrained national immunization programs, the current study outcomes can be used to help decision makers

Evaluation of biocompatibility and administration site reactogenicity of polyanhydride-particle-based platform for vaccine delivery.

PubMed

Huntimer, Lucas; Ramer-Tait, Amanda E; Petersen, Latrisha K; Ross, Kathleen A; Walz, Katherine A; Wang, Chong; Hostetter, Jesse; Narasimhan, Balaji; Wannemuehler, Michael J

2013-02-01

Efficacy, purity, safety, and potency are important attributes of vaccines. Polyanhydride particles represent a novel class of vaccine adjuvants and delivery platforms that have demonstrated the ability to enhance the stability of protein antigens as well as elicit protective immunity against bacterial pathogens. This work aims to elucidate the biocompatibility, inflammatory reactions, and particle effects on mice injected with a 5 mg dose of polyanhydride nanoparticles via common parenteral routes (subcutaneous and intramuscular). Independent of polymer chemistry, nanoparticles more effectively disseminated away from the injection site as compared to microparticles, which exhibited a depot effect. Using fluorescent probes, the in vivo distribution of three formulations of nanoparticles, following subcutaneous administration, indicated migration away from the injection site. Less inflammation was observed at the injection sites of mice-administered nanoparticles as compared to Alum and incomplete Freund's adjuvant. Furthermore, histological evaluation revealed minimal adverse injection site reactions and minimal toxicological effects associated with the administration of nanoparticles at 30 days post-administration. Collectively, these results demonstrate that polyanhydride nanoparticles do not induce inflammation as a cumulative effect of particle persistence or degradation and are, therefore, a viable candidate for a vaccine delivery platform. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Novel Non-Replication-Competent Cytomegalovirus Capsid Mutant Vaccine Strategy Is Effective in Reducing Congenital Infection

PubMed Central

Choi, K. Yeon; Root, Matthew

2016-01-01

ABSTRACT Congenital cytomegalovirus (CMV) infection is a leading cause of mental retardation and deafness in newborns. The guinea pig is the only small animal model for congenital CMV infection. A novel CMV vaccine was investigated as an intervention strategy against congenital guinea pig cytomegalovirus (GPCMV) infection. In this disabled infectious single-cycle (DISC) vaccine strategy, a GPCMV mutant virus was used that lacked the ability to express an essential capsid gene (the UL85 homolog GP85) except when grown on a complementing cell line. In vaccinated animals, the GP85 mutant virus (GP85 DISC) induced an antibody response to important glycoprotein complexes considered neutralizing target antigens (gB, gH/gL/gO, and gM/gN). The vaccine also generated a T cell response to the pp65 homolog (GP83), determined via a newly established guinea pig gamma interferon enzyme-linked immunosorbent spot assay. In a congenital infection protection study, GP85 DISC-vaccinated animals and a nonvaccinated control group were challenged during pregnancy with wild-type GPCMV (105 PFU). The pregnant animals carried the pups to term, and viral loads in target organs of pups were analyzed. Based on live pup births in the vaccinated and control groups (94.1% versus 63.6%), the vaccine was successful in reducing mortality (P = 0.0002). Additionally, pups from the vaccinated group had reduced CMV transmission, with 23.5% infected target organs versus 75.9% in the control group. Overall, these preliminary studies indicate that a DISC CMV vaccine strategy has the ability to induce an immune response similar to that of natural virus infection but has the increased safety of a non-replication-competent virus, which makes this approach attractive as a CMV vaccine strategy. IMPORTANCE Congenital CMV infection is a leading cause of mental retardation and deafness in newborns. An effective vaccine against CMV remains an elusive goal despite over 50 years of CMV research. The guinea pig, with

Association of chitosan and aluminium as a new adjuvant strategy for improved vaccination.

PubMed

Lebre, F; Bento, D; Ribeiro, J; Colaço, M; Borchard, G; de Lima, M C Pedroso; Borges, O

2017-07-15

The use of particulate adjuvants offers an interesting possibility to enhance and modulate the immune responses elicited by vaccines. Aluminium salts have been extensively used as vaccine adjuvants, but they lack the capacity to induce a strong cellular and mucosal immune response. Taking this into consideration, in this study we designed a new antigen delivery system combining aluminium salts with chitosan. Chitosan-aluminium nanoparticles (CH-Al NPs) exhibited a mean diameter of 280nm and a positive surface charge. The newly developed CH-Al NPs are more stable at physiological environment than classical CH NPs, showing no cytotoxic effects and revealing potential as a delivery system for a wide range of model antigens. In vivo studies showed that mice immunized with hepatitis B surface antigen (HBsAg)-containing CH NPs display high anti-HBsAg IgG titers in the serum, as well as the highest antigen-specific IgG on vaginal washes. Furthermore, in contrast to mice receiving antigen alone, mice immunized with the particulate adjuvant were able to elicit IgG2c antibody titers and exhibited higher antigen-specific IFN-γ levels in splenocytes. In conclusion, we established that CH-Al NPs, combining two immunostimulants to enhance both humoral and cellular immune responses, are a safe and promising system for antigen delivery. Our findings point towards their potential in future vaccination approaches. Copyright © 2017 Elsevier B.V. All rights reserved.

Patent data mining: a tool for accelerating HIV vaccine innovation.

PubMed

Clark, K; Cavicchi, J; Jensen, K; Fitzgerald, R; Bennett, A; Kowalski, S P

2011-05-31

Global access to advanced vaccine technologies is challenged by the interrelated components of intellectual property (IP) management strategies, technology transfer (legal and technical) capabilities and the capacity necessary for accelerating R&D, commercialization and delivery of vaccines. Due to a negative association with the management of IP, patents are often overlooked as a vast resource of freely available, information akin to scientific journals as well as business and technological information and trends fundamental for formulating policies and IP management strategies. Therefore, a fundamental step towards facilitating global vaccine access will be the assembly, organization and analysis of patent landscapes, to identify the amount of patenting, ownership (assignees) and fields of technology covered. This is critical for making informed decisions (e.g., identifying licensees, building research and product development collaborations, and ascertaining freedom to operate). Such information is of particular interest to the HIV vaccine community where the HIV Vaccine Enterprise, have voiced concern that IP rights (particularly patents and trade secrets) may prevent data and materials sharing, delaying progress in research and development of a HIV vaccine. We have compiled and analyzed a representative HIV vaccine patent landscape for a prime-boost, DNA/adenoviral vaccine platform, as an example for identifying obstacles, maximizing opportunities and making informed IP management strategy decisions towards the development and deployment of an efficacious HIV vaccine. Copyright © 2011 Elsevier Ltd. All rights reserved.

The cost-effectiveness of alternative vaccination strategies for polyvalent meningococcal vaccines in Burkina Faso: A transmission dynamic modeling study.

PubMed

Yaesoubi, Reza; Trotter, Caroline; Colijn, Caroline; Yaesoubi, Maziar; Colombini, Anaïs; Resch, Stephen; Kristiansen, Paul A; LaForce, F Marc; Cohen, Ted

2018-01-01

The introduction of a conjugate vaccine for serogroup A Neisseria meningitidis has dramatically reduced disease in the African meningitis belt. In this context, important questions remain about the performance of different vaccine policies that target remaining serogroups. Here, we estimate the health impact and cost associated with several alternative vaccination policies in Burkina Faso. We developed and calibrated a mathematical model of meningococcal transmission to project the disability-adjusted life years (DALYs) averted and costs associated with the current Base policy (serogroup A conjugate vaccination at 9 months, as part of the Expanded Program on Immunization [EPI], plus district-specific reactive vaccination campaigns using polyvalent meningococcal polysaccharide [PMP] vaccine in response to outbreaks) and three alternative policies: (1) Base Prime: novel polyvalent meningococcal conjugate (PMC) vaccine replaces the serogroup A conjugate in EPI and is also used in reactive campaigns; (2) Prevention 1: PMC used in EPI and in a nationwide catch-up campaign for 1-18-year-olds; and (3) Prevention 2: Prevention 1, except the nationwide campaign includes individuals up to 29 years old. Over a 30-year simulation period, Prevention 2 would avert 78% of the meningococcal cases (95% prediction interval: 63%-90%) expected under the Base policy if serogroup A is not replaced by remaining serogroups after elimination, and would avert 87% (77%-93%) of meningococcal cases if complete strain replacement occurs. Compared to the Base policy and at the PMC vaccine price of US$4 per dose, strategies that use PMC vaccine (i.e., Base Prime and Preventions 1 and 2) are expected to be cost saving if strain replacement occurs, and would cost US$51 (-US$236, US$490), US$188 (-US$97, US$626), and US$246 (-US$53, US$703) per DALY averted, respectively, if strain replacement does not occur. An important potential limitation of our study is the simplifying assumption that all

Pertussis vaccination coverage among French parents of infants after 10years of cocoon strategy.

PubMed

Cohen, R; Gaudelus, J; Denis, F; Stahl, J-P; Chevaillier, O; Pujol, P; Martinot, A

2016-06-01

The cocoon strategy against pertussis has been recommended in France since 2004 to indirectly protect young infants who are not yet vaccinated. We aimed to measure vaccination coverage among French parents of infants. A representative sample of 300 mothers and 200 fathers of infants aged <12 months completed a self-administered online questionnaire. They all provided their own vaccination records. Overall, 87% of mothers believed vaccination against pertussis to be important; 83% reported being immunized against pertussis but their vaccination records showed that a third of them was wrong (34%). On the basis of our sample, the 2009-2014 vaccination coverage against pertussis among mothers increased from 22 to 61% (P<0.005); over the same period of time, vaccination coverage against diphtheria, tetanus, and polio remained stable (80%). Vaccination coverage against pertussis among fathers increased from 21 to 42% between 2010 and 2013 (P=0.009). In 2013, one couple out of four (26%) was adequately immunized against pertussis. The cocoon strategy was implemented 10years ago in France but vaccination coverage remains suboptimal among parents of young infants. Healthcare professionals must recommend vaccination against pertussis to young adults and check that their vaccination status is up to date. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Vaccines and IP Rights: A Multifaceted Relationship.

PubMed

Durell, Karen

2016-01-01

Just as there are many forms of vaccines and components to vaccines-particular compositions, delivery systems, components, and distribution networks-there are a variety of intellectual property (IP) protections applicable for vaccines. IP rights such as patent, copyright, trademarks, plant breeders' rights, and trade secrets may all be applicable to vaccines. Thus, discussion of IP rights and vaccines should not begin and end with the application of one IP right to a vaccine. The discussion should engage considerations of multiple IP rights applicable to a vaccine and how these can be utilized in an integrated manner in a strategy aimed at supporting the development and distribution of the vaccine. Such an approach to IP rights to vaccines allows for the integrated rights to be considered in light of the justifications for protecting vaccines with IP rights, as well as the issues relating to specific IP rights for vaccines, such as compulsory license regimes, available humanitarian purpose IP credits, etc. To view vaccines as the subject of multiple IP protections involves a refocusing, but the outcome can provide significant benefits for vaccine development and distribution.

Current Strategies for Brain Drug Delivery

PubMed Central

Dong, Xiaowei

2018-01-01

The blood-brain barrier (BBB) has been a great hurdle for brain drug delivery. The BBB in healthy brain is a diffusion barrier essential for protecting normal brain function by impeding most compounds from transiting from the blood to the brain; only small molecules can cross the BBB. Under certain pathological conditions of diseases such as stroke, diabetes, seizures, multiple sclerosis, Parkinson's disease and Alzheimer disease, the BBB is disrupted. The objective of this review is to provide a broad overview on current strategies for brain drug delivery and related subjects from the past five years. It is hoped that this review could inspire readers to discover possible approaches to deliver drugs into the brain. After an initial overview of the BBB structure and function in both healthy and pathological conditions, this review re-visits, according to recent publications, some questions that are controversial, such as whether nanoparticles by themselves could cross the BBB and whether drugs are specifically transferred to the brain by actively targeted nanoparticles. Current non-nanoparticle strategies are also reviewed, such as delivery of drugs through the permeable BBB under pathological conditions and using non-invasive techniques to enhance brain drug uptake. Finally, one particular area that is often neglected in brain drug delivery is the influence of aging on the BBB, which is captured in this review based on the limited studies in the literature. PMID:29556336

Physician Knowledge and Attitudes About Hepatitis A and Current Practices Regarding Hepatitis A Vaccination Delivery.

PubMed

Nelson, Noele P; Allison, Mandy A; Lindley, Megan C; Brtnikova, Michaela; Crane, Lori A; Beaty, Brenda L; Hurley, Laura P; Kempe, Allison

2017-07-01

To assess physicians': 1) knowledge and attitudes about hepatitis A disease and hepatitis A (HepA) vaccine, 2) child care and school HepA vaccine mandates, 3) practices related to HepA vaccine delivery, 4) factors associated with strongly recommending HepA vaccine to all 1- to 2-year-olds, and 5) feasibility of implementing HepA catch-up vaccination at health maintenance visits. A national survey was conducted among representative networks of pediatricians and family medicine physicians (FMs) from March to June, 2014 via e-mail or mail on the basis of provider preference. Response rates were 81% (356 of 440) among pediatricians and 75% (348 of 464) among FMs. Less than 50% correctly identified that hepatitis A virus (HAV) infection is usually asymptomatic in young children and that morbidity from HAV disease increases with age. Ninety-two percent of pediatricians and 59% of FMs strongly recommend HepA vaccine for all 1- to 2-year-olds. In addition to practice specialty, belief that HepA vaccine is required for kindergarten enrollment was the most robust predictor of strong physician recommendation. Gaps in knowledge regarding HAV infection and hepatitis A recommendations and lack of a strong recommendation for routine HepA vaccination of young children among FMs likely contribute to suboptimal coverage. Closing knowledge gaps and addressing barriers that prevent all physicians from strongly recommending HepA vaccine to 1- to 2-year-olds could help increase HepA vaccine coverage and ultimately improve population protection against HAV infection. Published by Elsevier Inc.

Vaccines and vaccination strategies against human cutaneous leishmaniasis.

PubMed

Okwor, Ifeoma; Uzonna, Jude

2009-05-01

One might think that the development of a vaccine against cutaneous leishmaniasis would be relatively straightforward because the type of immune response required for protection is known and natural immunity occurs following recovery from primary infection. However, there is as yet no effective vaccine against the disease in humans. Although vaccination in murine studies has yielded promising results, these vaccines have failed miserably when tested in primates or humans. The reasons behind these failures are unknown and remain a major hurdle for vaccine design and development against cutaneous leishmaniasis. In contrast, recovery from natural, deliberate or experimental infections results in development of long-lasting immunity to re-infection. This so called infection-induced resistance is the strongest anti-Leishmania immunity known. Here, we briefly review the different approaches to vaccination against cutaneous leishmaniasis and argue that vaccines composed of genetically modified (attenuated) parasites, which induce immunity akin to infection-induced resistance, may provide best protection against cutaneous leishmaniasis in humans.

Going with the Grain of Cognition: Applying Insights from Psychology to Build Support for Childhood Vaccination

PubMed Central

Rossen, Isabel; Hurlstone, Mark J.; Lawrence, Carmen

2016-01-01

Childhood vaccination is widely considered to be one of the most successful public health interventions. Yet, the effective delivery of vaccination depends upon public willingness to vaccinate. Recently, many countries have faced problems with vaccine hesitancy, where a growing number of parents perceive vaccination to be unsafe or unnecessary, leading some to delay or refuse vaccines for their children. Effective intervention strategies for countering this problem are currently sorely lacking, however. Here, we propose that this may be because existing strategies are grounded more in intuition than insights from psychology. Consequently, such strategies are sometimes at variance with basic psychological principles and assumptions. By going against the grain of cognition, such strategies potentially run the risk of undermining persuasive efforts to reduce vaccine hesitancy. We demonstrate this by drawing on key insights from cognitive and social psychology to show how various known features of human psychology can lead many intuitively appealing intervention strategies to backfire, yielding unintended and undesirable repercussions. We conclude with a summary of potential avenues of investigation that may be more effective in addressing vaccine hesitancy. Our key message is that intervention strategies must be crafted that go with the grain of cognition by incorporating key insights from the psychological sciences. PMID:27746753

Anthrax vaccine powder formulations for nasal mucosal delivery.

PubMed

Jiang, Ge; Joshi, Sangeeta B; Peek, Laura J; Brandau, Duane T; Huang, Juan; Ferriter, Matthew S; Woodley, Wendy D; Ford, Brandi M; Mar, Kevin D; Mikszta, John A; Hwang, C Robin; Ulrich, Robert; Harvey, Noel G; Middaugh, C Russell; Sullivan, Vincent J

2006-01-01

Anthrax remains a serious threat worldwide as a bioterror agent. A second-generation anthrax vaccine currently under clinical evaluation consists of a recombinant Protective Antigen (rPA) of Bacillus anthracis. We have previously demonstrated that complete protection against inhalational anthrax can be achieved in a rabbit model, by intranasal delivery of a powder rPA formulation. Here we describe the preformulation and formulation development of such powder formulations. The physical stability of rPA was studied in solution as a function of pH and temperature using circular dichroism (CD), and UV-visible absorption and fluorescence spectroscopies. Extensive aggregation of rPA was observed at physiological temperatures. An empirical phase diagram, constructed using a combination of CD and fluorescence data, suggests that rPA is most thermally stable within the pH range of 6-8. To identify potential stabilizers, a library of GRAS excipients was screened using an aggregation sensitive turbidity assay, CD, and fluorescence. Based on these stability profiles, spray freeze-dried (SFD) formulations were prepared at pH 7-8 using trehalose as stabilizer and a CpG-containing oligonucleotide adjuvant. SFD formulations displayed substantial improvement in storage stability over liquid formulations. In combination with noninvasive intranasal delivery, such powder formulations may offer an attractive approach for mass biodefense immunization.

How does public policy impact cervical screening and vaccination strategies?☆

PubMed Central

Herzog, Thomas J.; Huh, Warner K.; Einstein, Mark H.

2011-01-01

Objectives To examine the current approaches to cervical screening and points to consider for improving HPV vaccination acceptance and uptake in the US. Methods An expert forum was conducted September 12–13, 2008, by the Society of Gynecologic Oncologists including 56 experts in cervical cancer and titled “Future Strategies of Cervical Cancer Prevention: What Do We Need to Do Now to Prepare?”. Results Cervical cancer prevention has primarily relied on screening paradigms but vaccination against human papillomavirus (HPV), the cause of the disease, is a primary preventative measure that has been recommended by all cervical cancer screening stakeholders. Guidelines for vaccination are developed by national advisory groups, but successful implementation requires a supportive infrastructure and the cooperation of providers, clinicians, and patients. HPV vaccination has been available in the United States (US) since 2006 and screening practices have been updated to also include HPV genotyping. However, many clinicians fail to adhere to the guidelines for HPV testing (and HPV co-testing) as part of cervical cancer screening, and vaccination coverage has been poor among females aged 11 and 12, the group for which vaccination is recommended by all organizations. Conclusions The data reviewed and presented in this session of the “Future Strategies of Cervical Cancer Prevention. What Do We Need to do Now to Prepare?”. The Forum suggests that the policies influencing HPV vaccination and screening need to be reassessed at multiple levels in order to achieve more effective implementation and regular use. PMID:20932433

Applying Genomic and Bioinformatic Resources to Human Adenovirus Genomes for Use in Vaccine Development and for Applications in Vector Development for Gene Delivery

PubMed Central

Seto, Jason; Walsh, Michael P.; Mahadevan, Padmanabhan; Zhang, Qiwei; Seto, Donald

2010-01-01

Technological advances and increasingly cost-effect methodologies in DNA sequencing and computational analysis are providing genome and proteome data for human adenovirus research. Applying these tools, data and derived knowledge to the development of vaccines against these pathogens will provide effective prophylactics. The same data and approaches can be applied to vector development for gene delivery in gene therapy and vaccine delivery protocols. Examination of several field strain genomes and their analyses provide examples of data that are available using these approaches. An example of the development of HAdV-B3 both as a vaccine and also as a vector is presented. PMID:21994597

Sex-based biology and the rational design of influenza vaccination strategies.

PubMed

Klein, Sabra L; Pekosz, Andrew

2014-07-15

Biological (ie, sex) differences as well as cultural (ie, gender) norms influence the acceptance and efficacy of vaccines for males and females. These differences are often overlooked in the design and implementation of vaccination strategies. Using seasonal and pandemic influenza vaccines, we document profound differences between the sexes in the acceptance, correlates of protection, and adverse reactions following vaccination in both young and older adults. Females develop higher antibody responses, experience more adverse reactions to influenza vaccines, and show greater vaccine efficacy than males. Despite greater vaccine efficacy in females, both young and older females are often less likely to accept influenza vaccines than their male counterparts. Identification of the biological mechanisms, including the hormones and genes, that underlie differential responses to vaccination is necessary. We propose that vaccines should be matched to an individual's biological sex, which could involve systematically tailoring diverse types of FDA-approved influenza vaccines separately for males and females. One goal for vaccines designed to protect against influenza and even other infectious diseases should be to increase the correlates of protection in males and reduce adverse reactions in females in an effort to increase acceptance and vaccine-induced protection in both sexes. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Vaccination of carp against SVCV with an oral DNA vaccine or an insect cells-based subunit vaccine.

PubMed

Embregts, C W E; Rigaudeau, D; Tacchi, L; Pijlman, G P; Kampers, L; Veselý, T; Pokorová, D; Boudinot, P; Wiegertjes, G F; Forlenza, M

2018-03-19

We recently reported on a successful vaccine for carp against SVCV based on the intramuscular injection of a DNA plasmid encoding the SVCV glycoprotein (SVCV-G). This shows that the intramuscular (i.m.) route of vaccination is suitable to trigger protective responses against SVCV, and that the SVCV G-protein is a suitable vaccine antigen. Yet, despite the general success of DNA vaccines, especially against fish rhabdoviruses, their practical implementation still faces legislative as well as consumer's acceptance concerns. Furthermore, the i.m. route of plasmid administration is not easily combined with most of the current vaccination regimes largely based on intraperitoneal or immersion vaccination. For this reason, in the current study we evaluated possible alternatives to a DNA-based i.m. injectable vaccine using the SVCV-G protein as the vaccine antigen. To this end, we tested two parallel approaches: the first based on the optimization of an alginate encapsulation method for oral delivery of DNA and protein antigens; the second based on the baculovirus recombinant expression of transmembrane SVCV-G protein in insect cells, administered as whole-cell subunit vaccine through the oral and injection route. In addition, in the case of the oral DNA vaccine, we also investigated the potential benefits of the mucosal adjuvants Escherichia coli lymphotoxin subunit B (LTB). Despite the use of various vaccine types, doses, regimes, and administration routes, no protection was observed, contrary to the full protection obtained with our reference i.m. DNA vaccine. The limited protection observed under the various conditions used in this study, the nature of the host, of the pathogen, the type of vaccine and encapsulation method, will therefore be discussed in details to provide an outlook for future vaccination strategies against SVCV. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Implementation research: reactive mass vaccination with single-dose oral cholera vaccine, Zambia.

PubMed

Poncin, Marc; Zulu, Gideon; Voute, Caroline; Ferreras, Eva; Muleya, Clara Mbwili; Malama, Kennedy; Pezzoli, Lorenzo; Mufunda, Jacob; Robert, Hugues; Uzzeni, Florent; Luquero, Francisco J; Chizema, Elizabeth; Ciglenecki, Iza

2018-02-01

To describe the implementation and feasibility of an innovative mass vaccination strategy - based on single-dose oral cholera vaccine - to curb a cholera epidemic in a large urban setting. In April 2016, in the early stages of a cholera outbreak in Lusaka, Zambia, the health ministry collaborated with Médecins Sans Frontières and the World Health Organization in organizing a mass vaccination campaign, based on single-dose oral cholera vaccine. Over a period of 17 days, partners mobilized 1700 health ministry staff and community volunteers for community sensitization, social mobilization and vaccination activities in 10 townships. On each day, doses of vaccine were delivered to vaccination sites and administrative coverage was estimated. Overall, vaccination teams administered 424 100 doses of vaccine to an estimated target population of 578 043, resulting in an estimated administrative coverage of 73.4%. After the campaign, few cholera cases were reported and there was no evidence of the disease spreading within the vaccinated areas. The total cost of the campaign - 2.31 United States dollars (US$) per dose - included the relatively low cost of local delivery - US$ 0.41 per dose. We found that an early and large-scale targeted reactive campaign using a single-dose oral vaccine, organized in response to a cholera epidemic within a large city, to be feasible and appeared effective. While cholera vaccines remain in short supply, the maximization of the number of vaccines in response to a cholera epidemic, by the use of just one dose per member of an at-risk community, should be considered.

Formulation of a dry powder influenza vaccine for nasal delivery.

PubMed

Garmise, Robert J; Mar, Kevin; Crowder, Timothy M; Hwang, C Robin; Ferriter, Matthew; Huang, Juan; Mikszta, John A; Sullivan, Vincent J; Hickey, Anthony J

2006-03-10

The purpose of this research was to prepare a dry powder vaccine formulation containing whole inactivated influenza virus (WIIV) and a mucoadhesive compound suitable for nasal delivery. Powders containing WIIV and either lactose or trehalose were produced by lyophilization. A micro-ball mill was used to reduce the lyophilized cake to sizes suitable for nasal delivery. Chitosan flakes were reduced in size using a cryo-milling technique. Milled powders were sieved between 45 and 125 microm aggregate sizes and characterized for particle size and distribution, morphology, and flow properties. Powders were blended in the micro-ball mill without the ball. Lyophilization followed by milling produced irregularly shaped, polydisperse particles with a median primary particle diameter of approximately 21 microm and a yield of approximately 37% of particles in the 45 to 125 microm particle size range. Flow properties of lactose and trehalose powders after lyophilization followed by milling and sieving were similar. Cryo-milling produced a small yield of particles in the desired size range (<10%). Lyophilization followed by milling and sieving produced particles suitable for nasal delivery with different physicochemical properties as a function of processing conditions and components of the formulation. Further optimization of particle size and morphology is required for these powders to be suitable for clinical evaluation.

Correlates of protection, antigen delivery and molecular epidemiology: basics for designing an HIV vaccine.

PubMed

Wagner, R; Shao, Y; Wolf, H

1999-03-26

Major obstacles in the development of HIV vaccines are the high variability of the virus and its complex interaction with the immune system. Recent studies demonstrated, that CTLs recognizing highly conserved epitopes in the group-specific antigen are capable of controlling HIV-replication in long-term nonprogressors. Necessary consequences for novel vaccine concepts are the presentation of a large repertoire of antigenic sites as well as the stimulation of different effectors of the immune system. Accordingly, different types of recombinant HIV-1 virus-like particles (VLPs) have been constructed stimulating the induction of neutralizing antibodies and HIV-specific CD8-positive CTL responses in preclinical studies. With respect to future vaccine trials, HIV vaccine formulations may need to be tailored to the local strains circulating within a geographical region. The expert group of the joint United Nations Programme on AIDS recently identified Yunnan, a southwestern province of China, as a region, in which the HIV epidemic is starting to gain speed, resembling to the situation in Thailand 10 years ago. A molecular clone of a representative virus strain is now available for the development of innovative antigen delivery systems aiming to be evaluated in future clinical vaccine trials throughout this area.

DIVA--a vaccination strategy enabling the detection of field exposure to avian influenza.

PubMed

Capua, I; Cattoli, G; Marangon, S

2004-01-01

The present paper reports on the development, validation and field application of a control strategy for avian influenza infections in poultry. The "DIVA" (Differentiating Infected from Vaccinated Animals) strategy is based on the use of an inactivated oil emulsion vaccine containing the same haemagglutinin (H) subtype as the challenge virus, but a different neuraminidase (N). The possibility of using the heterologous N subtype, to differentiate between vaccinated and naturally infected birds, was investigated through the development of an "ad hoc" serological test based on the detection of specific anti-N antibodies. This test is based on an indirect fluorescent antibody assay, using as an antigen a baculovirus expressing recombinant N proteins. The vaccination strategy has been tested in the laboratory and shown to be efficacious both against challenge with highly pathogenic AI viruses and with low pathogenicity AI viruses, ensuring clinical protection, reduction of duration and titre of shedding. In addition, vaccination resulted in an increased resistance to infection. The companion diagnostic tests directed to the detection of anti-N1 and anti-N3 antibodies have been validated in the laboratory and using field samples. The serological assay showed an "almost perfect agreement" (Kappa value) with the HI test, with relative sensitivity and specificity values of 98.1 and 95.7, respectively. The results of the present investigation suggest that the "DIVA" control strategy may represent a tool to support the eradication of avian influenza infections in poultry.

[The development of novel tumor targeting delivery strategy].

PubMed

Gao, Hui-le; Jiang, Xin-guo

2016-02-01

Tumor is one of the most serious threats for human being. Although many anti-tumor drugs are approved for clinical use, the treatment outcome is still modest because of the poor tumor targeting efficiency and low accumulation in tumor. Therefore, it is important to deliver anti-tumor drug into tumor efficiently, elevate drug concentration in tumor tissues and reduce the drug distribution in normal tissues. And it has been one of the most attractive directions of pharmaceutical academy and industry. Many kinds of strategies, especially various nanoparticulated drug delivery systems, have been developed to address the critical points of complex tumor microenvironment, which are partially or mostly satisfied for tumor treatment. In this paper, we carefully reviewed the novel targeting delivery strategies developed in recent years. The most powerful method is passive targeting delivery based on the enhanced permeability and retention(EPR) effect, and most commercial nanomedicines are based on the EPR effect. However, the high permeability and retention require different particle sizes, thus several kinds of size-changeable nanoparticles are developed, such as size reducible particles and assemble particles, to satisfy the controversial requirement for particle size and enhance both tumor retention and penetration. Surface charge reversible nanoparticles also shows a high efficiency because the anionic charge in blood circulation and normal organs decrease the unintended internalization. The charge can change into positive in tumor microenvironment, facilitating drug uptake by tumor cells. Additionally, tumor microenvironment responsive drug release is important to decrease drug side effect, and many strategies are developed, such as p H sensitive release and enzyme sensitive release. Except the responsive nanoparticles, shaping tumor microenvironment could attenuate the barriers in drug delivery, for example, decreasing tumor collagen intensity and normalizing tumor

Poly(Lactic Acid) Nanoparticles Targeting α5β1 Integrin as Vaccine Delivery Vehicle, a Prospective Study

PubMed Central

Gutjahr, Alice; Terrat, Céline; Exposito, Jean-Yves; Verrier, Bernard; Lethias, Claire

2016-01-01

Biodegradable polymeric nanoparticles are vehicles of choice for drug delivery and have the ability to encapsulate and present at their surface different molecules of interest. Among these bio-nanocarriers, poly(lactic acid) (PLA) nanoparticles have been used as adjuvant and vehicle for enhanced vaccine efficacy. In order to develop an approach to efficient vaccine delivery, we developed nanoparticles to target α5β1 positive cells. We first overproduced, in bacteria, human fibronectin FNIII9/10 recombinant proteins possessing an integrin α5β1 binding site, the RGDS sequence, or a mutated form of this site. After having confirmed the integrin binding properties of these recombinant proteins in cell culture assays, we were able to formulate PLA nanoparticles with these FNIII9/10 proteins at their surface. We then confirmed, by fluorescence and confocal microscopy, an enhanced cellular uptake by α5β1+ cells of RGDS-FNIII9/10 coated PLA nanoparticles, in comparison to KGES-FNIII9/10 coated or non-coated controls. As a first vaccination approach, we prepared PLA nanoparticles co-coated with p24 (an HIV antigen), and RGDS- or KGES-FNIII9/10 proteins, followed by subcutaneous vaccine administration, in mice. Although we did not detect improvements in the apparent humoral response to p24 antigen in the serum of RGDS/p24 nanoparticle-treated mice, the presence of the FNIII proteins increased significantly the avidity index of anti-p24 antibodies compared to p24-nanoparticle-injected control mice. Future developments of this innovative targeted vaccine are discussed. PMID:27973577

The projected effectiveness of Clostridium difficile vaccination as part of an integrated infection control strategy.

PubMed

van Kleef, Esther; Deeny, Sarah R; Jit, Mark; Cookson, Barry; Goldenberg, Simon D; Edmunds, W John; Robotham, Julie V

2016-11-04

Early clinical trials of a Clostridium difficile toxoid vaccine show efficacy in preventing C. difficile infection (CDI). The optimal patient group to target for vaccination programmes remains unexplored. This study performed a model-based evaluation of the effectiveness of different CDI vaccination strategies, within the context of existing infection prevention and control strategies such as antimicrobial stewardship. An individual-based transmission model of CDI in a high-risk hospital setting was developed. The model incorporated data on patient movements between the hospital, and catchment populations from the community and long-term care facilities (LTCF), using English national and local level data for model-parameterisation. We evaluated vaccination of: (1) discharged patients who had an CDI-occurrence in the ward; (2) LTCF-residents; (3) Planned elective surgical admissions and (4) All three strategies combined. Without vaccination, 10.9 [Interquartile range: 10.0-11.8] patients per 1000 ward admissions developed CDI, of which 31% were ward-acquired. Immunising all three patient groups resulted in a 43% [42-44], reduction of ward-onset CDI on average. Among the strategies restricting vaccination to one target group, vaccinating elective surgical patients proved most effective (35% [34-36] reduction), but least efficient, requiring 146 [133-162] courses to prevent one ICU-onset case. Immunising LTCF residents was most efficient, requiring just 13 [11-16] courses to prevent one case, but considering this only comprised a small group of our hospital population, it only reduced ICU-onset CDI by 9% [8-11]. Vaccination proved most efficient when ward-based transmission rates and antimicrobial consumption were high. Strategy success depends on the interaction between hospital and catchment populations, and importantly, consideration of importations of CDI from outside the hospital which we found to substantially impact hospital dynamics. Vaccination may be most

Engineering nanoparticle-coated bacteria as oral DNA vaccines for cancer immunotherapy.

PubMed

Hu, Qinglian; Wu, Min; Fang, Chun; Cheng, Changyong; Zhao, Mengmeng; Fang, Weihuan; Chu, Paul K; Ping, Yuan; Tang, Guping

2015-04-08

Live attenuated bacteria are of increasing importance in biotechnology and medicine in the emerging field of cancer immunotherapy. Oral DNA vaccination mediated by live attenuated bacteria often suffers from low infection efficiency due to various biological barriers during the infection process. To this end, we herein report, for the first time, a new strategy to engineer cationic nanoparticle-coated bacterial vectors that can efficiently deliver oral DNA vaccine for efficacious cancer immunotherapy. By coating live attenuated bacteria with synthetic nanoparticles self-assembled from cationic polymers and plasmid DNA, the protective nanoparticle coating layer is able to facilitate bacteria to effectively escape phagosomes, significantly enhance the acid tolerance of bacteria in stomach and intestines, and greatly promote dissemination of bacteria into blood circulation after oral administration. Most importantly, oral delivery of DNA vaccines encoding autologous vascular endothelial growth factor receptor 2 (VEGFR2) by this hybrid vector showed remarkable T cell activation and cytokine production. Successful inhibition of tumor growth was also achieved by efficient oral delivery of VEGFR2 with nanoparticle-coated bacterial vectors due to angiogenesis suppression in the tumor vasculature and tumor necrosis. This proof-of-concept work demonstrates that coating live bacterial cells with synthetic nanoparticles represents a promising strategy to engineer efficient and versatile DNA vaccines for the era of immunotherapy.

Meeting the preteen vaccine law: a pilot program in urban middle schools.

PubMed

Boyer-Chuanroong, L; Deaver, P

2000-02-01

California, the most populous state in the nation, is one of many states that implemented vaccination requirements for preteens. While kindergarten requirements are well-established and accepted by parents, implementation of preteen vaccination requirements requires inter- and intra-institutional adjustments, educational and public relations efforts, and an augmentation of vaccination delivery systems. This article describes a pilot program in two middle schools in an urban school district and offers planning strategies and practical tools to assist school nurses and health providers to implement preteen requirements.

Modelling Vaccination Strategies against Rift Valley Fever in Livestock in Kenya.

PubMed

Gachohi, John M; Njenga, M Kariuki; Kitala, Philip; Bett, Bernard

2016-12-01

The impacts of vaccination on the transmission of Rift Valley fever virus (RVFV) have not been evaluated. We have developed a RVFV transmission model comprising two hosts-cattle as a separate host and sheep and goats as one combined host (herein after referred to as sheep)-and two vectors-Aedes species (spp) and Culex spp-and used it to predict the impacts of: (1) reactive vaccination implemented at various levels of coverage at pre-determined time points, (2) targeted vaccination involving either of the two host species, and (3) a periodic vaccination implemented biannually or annually before an outbreak. The model comprises coupled vector and host modules where the dynamics of vectors and hosts are described using a system of difference equations. Vector populations are structured into egg, larva, pupa and adult stages and the latter stage is further categorized into three infection categories: susceptible, exposed and infectious mosquitoes. The survival rates of the immature stages (egg, larva and pupa) are dependent on rainfall densities extracted from the Tropical Rainfall Measuring Mission (TRMM) for a Rift Valley fever (RVF) endemic site in Kenya over a period of 1827 days. The host populations are structured into four age classes comprising young, weaners, yearlings and adults and four infection categories including susceptible, exposed, infectious, and immune categories. The model reproduces the 2006/2007 RVF outbreak reported in empirical surveys in the target area and other seasonal transmission events that are perceived to occur during the wet seasons. Mass reactive vaccination strategies greatly reduce the potential for a major outbreak. The results also suggest that the effectiveness of vaccination can be enhanced by increasing the vaccination coverage, targeting vaccination on cattle given that this species plays a major role in the transmission of the virus, and using both periodic and reactive vaccination strategies. Reactive vaccination can be

Health economic evaluation of vaccination strategies for the prevention of herpes zoster and postherpetic neuralgia in Germany.

PubMed

Ultsch, Bernhard; Weidemann, Felix; Reinhold, Thomas; Siedler, Anette; Krause, Gérard; Wichmann, Ole

2013-09-26

Herpes zoster (HZ) is a self-limiting painful skin rash affecting mostly individuals from 50 years of age. The main complication is postherpetic neuralgia (PHN), a long-lasting pain after rash has resolved. A HZ-vaccine has recently been licensed in Europe for individuals older than 50 years. To support an informed decision-making for a potential vaccination recommendation, we conducted a health economic evaluation to identify the most cost-effective vaccination strategy. We developed a static Markov-cohort model, which compared a vaccine-scenario with no vaccination. The cohort entering the model was 50 years of age, vaccinated at age 60, and stayed over life-time in the model. Transition probabilities were based on HZ/PHN-epidemiology and demographic data from Germany, as well as vaccine efficacy (VE) data from clinical trials. Costs for vaccination and HZ/PHN-treatment (in Euros; 2010), as well as outcomes were discounted equally with 3% p.a. We accounted results from both, payer and societal perspective. We calculated benefit-cost-ratio (BCR), number-needed-to-vaccinate (NNV), and incremental cost-effectiveness ratios (ICERs) for costs per HZ-case avoided, per PHN-case avoided, and per quality-adjusted life-year (QALY) gained. Different target age-groups were compared to identify the most cost-effective vaccination strategy. Base-case-analysis as well as structural, descriptive-, and probabilistic-sensitivity-analyses (DSA, PSA) were performed. When vaccinating 20% of a cohort of 1 million 50 year old individuals at the age of 60 years, approximately 20,000 HZ-cases will be avoided over life-time. The NNV to avoid one HZ (PHN)-case was 10 (144). However, with a BCR of 0.34 this vaccination-strategy did not save costs. The base-case-analysis yielded an ICER of 1,419 (20,809) Euros per avoided HZ (PHN)-case and 28,146 Euros per QALY gained. Vaccination at the age of 60 was identified in most (sensitivity) analyses to be the most cost-effective vaccination

Health economic evaluation of vaccination strategies for the prevention of herpes zoster and postherpetic neuralgia in Germany

PubMed Central

2013-01-01

Background Herpes zoster (HZ) is a self-limiting painful skin rash affecting mostly individuals from 50 years of age. The main complication is postherpetic neuralgia (PHN), a long-lasting pain after rash has resolved. A HZ-vaccine has recently been licensed in Europe for individuals older than 50 years. To support an informed decision-making for a potential vaccination recommendation, we conducted a health economic evaluation to identify the most cost-effective vaccination strategy. Methods We developed a static Markov-cohort model, which compared a vaccine-scenario with no vaccination. The cohort entering the model was 50 years of age, vaccinated at age 60, and stayed over life-time in the model. Transition probabilities were based on HZ/PHN-epidemiology and demographic data from Germany, as well as vaccine efficacy (VE) data from clinical trials. Costs for vaccination and HZ/PHN-treatment (in Euros; 2010), as well as outcomes were discounted equally with 3% p.a. We accounted results from both, payer and societal perspective. We calculated benefit-cost-ratio (BCR), number-needed-to-vaccinate (NNV), and incremental cost-effectiveness ratios (ICERs) for costs per HZ-case avoided, per PHN-case avoided, and per quality-adjusted life-year (QALY) gained. Different target age-groups were compared to identify the most cost-effective vaccination strategy. Base-case-analysis as well as structural, descriptive-, and probabilistic-sensitivity-analyses (DSA, PSA) were performed. Results When vaccinating 20% of a cohort of 1 million 50 year old individuals at the age of 60 years, approximately 20,000 HZ-cases will be avoided over life-time. The NNV to avoid one HZ (PHN)-case was 10 (144). However, with a BCR of 0.34 this vaccination-strategy did not save costs. The base-case-analysis yielded an ICER of 1,419 (20,809) Euros per avoided HZ (PHN)-case and 28,146 Euros per QALY gained. Vaccination at the age of 60 was identified in most (sensitivity) analyses to be the most cost

Development of Peptide Vaccines in Dengue.

PubMed

Reginald, Kavita; Chan, Yanqi; Plebanski, Magdalena; Poh, Chit Laa

2017-09-13

Dengue is one of the most important arboviral infection worldwide, infecting up to 390 million people and causing 25,000 deaths annually. Although a licensed dengue vaccine is available, it is not efficacious against dengue serotypes that infect people living in South East Asia, where dengue is an endemic disease. Hence, there is an urgent need to develop an efficient dengue vaccine for this region. Data from different clinical trials indicate that a successful dengue vaccine must elicit both neutralizing antibodies and cell mediated immunity. This can be achieved by designing a multi-epitope peptide vaccine comprising B, CD8+ and CD4+ T cell epitopes. As recognition of T cell epitopes are restricted by human leukocyte antigens (HLA), T cell epitopes which are able to recognize several major HLAs will be preferentially included in the vaccine design. While peptide vaccines are safe, biocompatible and cost-effective, it is poorly immunogenic. Strategies to improve its immunogenicity by the use of long peptides, adjuvants and nanoparticle delivery mechanisms are discussed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Vaccination strategies for future influenza pandemics: a severity-based cost effectiveness analysis

PubMed Central

2013-01-01

Background A critical issue in planning pandemic influenza mitigation strategies is the delay between the arrival of the pandemic in a community and the availability of an effective vaccine. The likely scenario, born out in the 2009 pandemic, is that a newly emerged influenza pandemic will have spread to most parts of the world before a vaccine matched to the pandemic strain is produced. For a severe pandemic, additional rapidly activated intervention measures will be required if high mortality rates are to be avoided. Methods A simulation modelling study was conducted to examine the effectiveness and cost effectiveness of plausible combinations of social distancing, antiviral and vaccination interventions, assuming a delay of 6-months between arrival of an influenza pandemic and first availability of a vaccine. Three different pandemic scenarios were examined; mild, moderate and extreme, based on estimates of transmissibility and pathogenicity of the 2009, 1957 and 1918 influenza pandemics respectively. A range of different durations of social distancing were examined, and the sensitivity of the results to variation in the vaccination delay, ranging from 2 to 6 months, was analysed. Results Vaccination-only strategies were not cost effective for any pandemic scenario, saving few lives and incurring substantial vaccination costs. Vaccination coupled with long duration social distancing, antiviral treatment and antiviral prophylaxis was cost effective for moderate pandemics and extreme pandemics, where it saved lives while simultaneously reducing the total pandemic cost. Combined social distancing and antiviral interventions without vaccination were significantly less effective, since without vaccination a resurgence in case numbers occurred as soon as social distancing interventions were relaxed. When social distancing interventions were continued until at least the start of the vaccination campaign, attack rates and total costs were significantly lower, and

Vaccination strategies for future influenza pandemics: a severity-based cost effectiveness analysis.

PubMed

Kelso, Joel K; Halder, Nilimesh; Milne, George J

2013-02-11

A critical issue in planning pandemic influenza mitigation strategies is the delay between the arrival of the pandemic in a community and the availability of an effective vaccine. The likely scenario, born out in the 2009 pandemic, is that a newly emerged influenza pandemic will have spread to most parts of the world before a vaccine matched to the pandemic strain is produced. For a severe pandemic, additional rapidly activated intervention measures will be required if high mortality rates are to be avoided. A simulation modelling study was conducted to examine the effectiveness and cost effectiveness of plausible combinations of social distancing, antiviral and vaccination interventions, assuming a delay of 6-months between arrival of an influenza pandemic and first availability of a vaccine. Three different pandemic scenarios were examined; mild, moderate and extreme, based on estimates of transmissibility and pathogenicity of the 2009, 1957 and 1918 influenza pandemics respectively. A range of different durations of social distancing were examined, and the sensitivity of the results to variation in the vaccination delay, ranging from 2 to 6 months, was analysed. Vaccination-only strategies were not cost effective for any pandemic scenario, saving few lives and incurring substantial vaccination costs. Vaccination coupled with long duration social distancing, antiviral treatment and antiviral prophylaxis was cost effective for moderate pandemics and extreme pandemics, where it saved lives while simultaneously reducing the total pandemic cost. Combined social distancing and antiviral interventions without vaccination were significantly less effective, since without vaccination a resurgence in case numbers occurred as soon as social distancing interventions were relaxed. When social distancing interventions were continued until at least the start of the vaccination campaign, attack rates and total costs were significantly lower, and increased rates of vaccination

Farmers' perception of the role of veterinary surgeons in vaccination strategies on British dairy farms.

PubMed

Richens, I F; Hobson-West, P; Brennan, M L; Lowton, R; Kaler, J; Wapenaar, W

2015-11-07

There is limited research investigating the motivators and barriers to vaccinating dairy cattle. Veterinary surgeons have been identified as important sources of information for farmers making vaccination and disease control decisions, as well as being farmers' preferred vaccine suppliers. Vets' perception of their own role and communication style can be at odds with farmers' reported preferences. The objective of this study was to investigate how dairy farmers perceived the role of vets in implementing vaccination strategies on their farm. Semi-structured interviews were conducted with 24 dairy farmers from across Britain. The data were analysed using thematic analysis. Analysis revealed that farmers perceive vets to have an important role in facilitating decision-making in all aspects of vaccination, including the aspects of vaccine distribution and advice on implementation. This important role is acknowledged by farmers who have regular veterinary contact, but also farmers with solely emergency veterinary contact. Given this finding, future work should investigate the attitudes of vets towards vaccination and how they perceive their role. Combining this knowledge will enable optimisation of vaccination strategies on British dairy farms. British Veterinary Association.

[Immunization strategy of hepatitis B vaccine among adults in China: evidence based-medicine and consideration].

PubMed

Xu, A Q; Zhang, L

2016-06-01

With the effective control of hepatitis B infection among children, the adults especial the young ones become the main population for new hepatitis B virus infection. Now the adults receive hepatitis B vaccination voluntarily and at their own expense in China and the coverage is low. The high immunogenicity of hepatitis B vaccine has been proven among healthy adults. Although the safety of hepatitis B vaccination has been documented among high-risk population such as HIV-infected people, injecting drug users and patients with chronic hepatitis disease, their antibody seroconversion rate after hepatitis B vaccination is lower than the healthy adults. Hepatitis B vaccination is recommended to population at high risk officially in many countries and some effects have been achieved. It is urgent to improve the strategy of hepatitis B vaccination among adults to fasten the control of hepatitis B in China, along with the researches about the long-term efficacy of hepatitis B vaccine among adults, the immunogenicity of hepatitis B vaccination among high-risk adults and the economical evaluation about different adult immunization strategy of hepatitis B.

Oral delivery of BCG Moreau Rio de Janeiro gives equivalent protection against tuberculosis but with reduced pathology compared to parenteral BCG Danish vaccination.

PubMed

Clark, Simon O; Kelly, Dominic L F; Badell, Edgar; Castello-Branco, Luiz Roberto; Aldwell, Frank; Winter, Nathalie; Lewis, David J M; Marsh, Philip D

2010-10-08

There is a need for an improved vaccine to better control human tuberculosis (TB), as the only currently available TB vaccine, bacillus Calmette-Guerin (BCG) delivered parenterally, offers variable levels of efficacy. Therefore, recombinant strains expressing additional antigens are being developed alongside alternative routes to parenteral delivery. There is strong evidence that BCG Moreau (RdJ) is a safe and effective vaccine in humans when given by the oral route. This study compared the efficacy of a single oral dose of wild type BCG Moreau Rio de Janeiro (RdJ), or a recombinant RdJ strain expressing Ag85B-ESAT6 fusion protein, formulated with and without lipid to enhance oral delivery, with subcutaneous BCG Danish 1331 and saline control groups in a guinea pig aerosol infection model of pulmonary tuberculosis. Protection was measured as survival at 30 weeks post-challenge and reduced bacterial load and histopathology in lungs and spleen. Results showed that a single oral dose of BCG Moreau (RdJ) or recombinant BCG Moreau (RdJ)-Ag85B-ESAT6, formulated with or without lipid, gave protection equivalent to subcutaneously delivered BCG Danish in the 30 weeks post-challenge survival study. The orally delivered vaccines gave reduced pathology scores in the lungs (three of the four formulations) and spleens (all four formulations) compared to subcutaneously delivered BCG Danish. The oral wild type BCG Moreau (RdJ) in lipid and the unformulated oral wild type BCG Moreau (RdJ) vaccine also gave statistically lower bacterial loads in the lungs and spleens, respectively, compared to subcutaneously delivered BCG Danish. This study provides further evidence to show that lipid formulation does not impair vaccine efficacy and may enhance the delivery and stability of oral vaccines intended for use in countries with poor health infrastructure. Oral delivery also avoids needles (and associated cross-infection risks) and immunisation without the need for specially trained

Stabilization challenges and formulation strategies associated with oral biologic drug delivery systems.

PubMed

Truong-Le, Vu; Lovalenti, Phillip M; Abdul-Fattah, Ahmad M

2015-10-01

Delivery of proteins to mucosal tissues of GI tract typically utilize formulations which protect against proteolysis and target the mucosal tissues. Using case studies from literature and the authors' own work, the in-process stability and solid state storage stability of biopharmaceuticals formulated in delivery systems designed for oral delivery to the GI tract will be reviewed. Among the range of delivery systems, biodegradable polymer systems for protection and controlled release of proteins have been the most studied; hence these systems will be covered in greater depth. These delivery systems include polymeric biodegradable microspheres or nanospheres that contain proteins or vaccines, which are designed to reduce the number of administrations/inoculations and the total protein dose required to achieve the desired biological effect. Specifically, this review will include a landscape survey of the systems that have been studied, the manufacturing processes involved, stability through the manufacturing process, key pharmaceutical formulation parameters that impact stability of the encased proteins, and storage stability of the encapsulated proteins in these delivery systems. Copyright © 2015 Elsevier B.V. All rights reserved.

A game dynamic model for delayer strategies in vaccinating behaviour for pediatric infectious diseases.

PubMed

Bhattacharyya, Samit; Bauch, C T

2010-12-07

Several studies have found that some parents delay the age at which their children receive pediatric vaccines due to perception of higher vaccine risk at the recommended age of vaccination. This has been particularly apparently during the Measles-Mumps-Rubella scare in the United Kingdom. Under a voluntary vaccination policy, vaccine coverage in certain age groups is a potentially complex interplay between vaccinating behaviour, disease dynamics, and age-specific risk factors. Here, we construct an age-structured game dynamic model, where individuals decide whether to vaccinate according to imitation dynamics depending on age-dependent disease prevalence and perceived risk of vaccination. Individuals may be timely vaccinators, delayers, or non-vaccinators. The model exhibits multiple equilibria and a broad range of possible dynamics. For certain parameter regimes, the proportion of timely vaccinators and delayers oscillate in an anti-phase fashion in response to oscillations in infection prevalence. Under an exogenous change to the perceived risk of vaccination as might occur during a vaccine scare, the model can also capture an increase in delayer strategists similar in magnitude to that observed during the Measles-Mumps-Rubella vaccine scare in the United Kingdom. Our model also shows that number of delayers steadily increases with increasing severity of the scare, whereas it saturates to specific value with increases in duration of the scare. Finally, by comparing the model dynamics with and without the option of a delayer strategy, we show that adding a third delayer strategy can have a stabilizing effect on model dynamics. In an era where individual choice--rather than accessibility--is becoming an increasingly important determinant of vaccine uptake, more infectious disease models may need to use game theory or related techniques to determine vaccine uptake. Copyright © 2010 Elsevier Ltd. All rights reserved.

Effectiveness and Cost-Effectiveness of Expanded Antiviral Prophylaxis and Adjuvanted Vaccination Strategies for the Next Influenza Pandemic

PubMed Central

Khazeni, Nayer; Hutton, David W; Garber, Alan M; Owens, Douglas K

2011-01-01

Background The pandemic potential of the influenza A (H5N1) virus is among the greatest public health concerns of the 21st century. Objective To determine the effectiveness and cost-effectiveness of alternative pandemic mitigation and response strategies. Design Compartmental epidemic model in conjunction with a Markov model of disease progression. Data Sources Literature and expert opinion. Target Population Residents of a U.S. metropolitan city. Time Horizon Lifetime. Perspective Societal. Interventions One mitigation strategy used non-pharmaceutical interventions, vaccination, and antiviral pharmacotherapy in quantities similar to those available currently in the U.S. stockpile. The second and third strategies used expanded supplies of either antivirals (expanded antiviral prophylaxis strategy) or adjuvanted vaccine (expanded vaccination strategy) in addition to non-pharmaceutical interventions. Outcome Measures Infections and deaths averted, costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness. Results of Base Case Analysis The stockpiled strategy averted 44% of infections and deaths, gaining 258,342 QALYs at $8,907 per QALY gained relative to no intervention. Expanded antiviral prophylaxis delayed the pandemic, averting 48% of infections and deaths, and gaining 282,329 QALYs, with a less favorable cost-effectiveness ratio than adjuvanted vaccination. Adjuvanted vaccination was the most effective strategy and was cost-effective, averting 68% of infections and deaths, and gaining 404,030 QALYs at $10,844 per QALY gained relative to stockpiled strategy. Results of Sensitivity Analysis Over a wide range of assumptions, the incremental cost-effectiveness ratio of the expanded adjuvanted vaccination strategy was less than $50,000 per QALY gained. Limitations Large groups and frequent contacts may spread the virus more rapidly. The model is not designed to target interventions to specific groups. Conclusions Expanded adjuvanted vaccination

Engineering T7 bacteriophage as a potential DNA vaccine targeting delivery vector.

PubMed

Xu, Hai; Bao, Xi; Wang, Yiwei; Xu, Yue; Deng, Bihua; Lu, Yu; Hou, Jibo

2018-03-20

DNA delivery with bacteriophage by surface-displayed mammalian cell penetrating peptides has been reported. Although, various phages have been used to facilitate DNA transfer by surface displaying the protein transduction domain of human immunodeficiency virus type 1 Tat protein (Tat peptide), no similar study has been conducted using T7 phage. In this study, we engineeredT7 phage as a DNA targeting delivery vector to facilitate cellular internalization. We constructed recombinant T7 phages that displayed Tat peptide on their surface and carried eukaryotic expression box (EEB) as a part of their genomes (T7-EEB-Tat). We demonstrated that T7 phage harboring foreign gene insertion had packaged into infective progeny phage particles. Moreover, when mammalian cells that were briefly exposed to T7-EEB-Tat, expressed a significant higher level of the marker gene with the control cells infected with the wide type phage without displaying Tat peptides. These data suggested that the potential of T7 phage as an effective delivery vector for DNA vaccine transfer.

Potent Immune Responses in Rhesus Macaques Induced by Nonviral Delivery of a Self-amplifying RNA Vaccine Expressing HIV Type 1 Envelope With a Cationic Nanoemulsion

PubMed Central

Bogers, Willy M.; Oostermeijer, Herman; Mooij, Petra; Koopman, Gerrit; Verschoor, Ernst J.; Davis, David; Ulmer, Jeffrey B.; Brito, Luis A.; Cu, Yen; Banerjee, Kaustuv; Otten, Gillis R.; Burke, Brian; Dey, Antu; Heeney, Jonathan L.; Shen, Xiaoying; Tomaras, Georgia D.; Labranche, Celia; Montefiori, David C.; Liao, Hua-Xin; Haynes, Barton; Geall, Andrew J.; Barnett, Susan W.

2015-01-01

Self-amplifying messenger RNA (mRNA) of positive-strand RNA viruses are effective vectors for in situ expression of vaccine antigens and have potential as a new vaccine technology platform well suited for global health applications. The SAM vaccine platform is based on a synthetic, self-amplifying mRNA delivered by a nonviral delivery system. The safety and immunogenicity of an HIV SAM vaccine encoding a clade C envelope glycoprotein formulated with a cationic nanoemulsion (CNE) delivery system was evaluated in rhesus macaques. The HIV SAM vaccine induced potent cellular immune responses that were greater in magnitude than those induced by self-amplifying mRNA packaged in a viral replicon particle (VRP) or by a recombinant HIV envelope protein formulated with MF59 adjuvant, anti-envelope binding (including anti-V1V2), and neutralizing antibody responses that exceeded those induced by the VRP vaccine. These studies provide the first evidence in nonhuman primates that HIV vaccination with a relatively low dose (50 µg) of formulated self-amplifying mRNA is safe and immunogenic. PMID:25234719

PLGA particulate subunit tuberculosis vaccines promote humoral and Th17 responses but do not enhance control of Mycobacterium tuberculosis infection

PubMed Central

Parumasivam, Thaigarajan; Chan, John Gar Yan; Lin, Leon C. W.; Flórido, Manuela; West, Nicholas P.; Chan, Hak-Kim; Britton, Warwick J.

2018-01-01

Tuberculosis places a staggering burden on human health globally. The new World Health Organisation End-TB Strategy has highlighted the urgent need for more effective TB vaccines to improve control of the disease. Protein-based subunit vaccines offer potential as safe and effective generators of protective immunity, and the use of particulate vaccine formulation and delivery by the pulmonary route may enhance local immunogenicity. In this study, novel particulate subunit vaccines were developed utilising biodegradable poly(lactic-co-glycolic acid) (PLGA) slow-release particles as carriers for the Mycobacterium tuberculosis lipoprotein MPT83, together with the adjuvants trehalose-dibehenate (TDB) or Monophosphoryl lipid A (MPL). Following delivery by the pulmonary or subcutaneous routes, the immunogenicity and protective efficacy of these vaccines were assessed in a murine model of M. tuberculosis infection. When delivered peripherally, these vaccines induced modest, antigen-specific Th1 and Th17 responses, but strong anti-MPT83 antibody responses. Mucosal delivery of the PLGA(MPT83) vaccine, with or without TDB, increased antigen-specific Th17 responses in the lungs, however, PLGA-encapsulated vaccines did not provide protection against M. tuberculosis challenge. By contrast, peripheral delivery of DDA liposomes containing MPT83 and TDB or MPL, stimulated both Th1 and Th17 responses and generated protection against M. tuberculosis challenge. Therefore, PLGA-formulated vaccines primarily stimulate strong humoral immunity, or Th17 responses if used mucosally, and may be a suitable carrier for vaccines against extracellular pathogens. This study emphasises the critical nature of the vaccine carrier, adjuvant and route of delivery for optimising vaccine efficacy against TB. PMID:29554138

Implementation research: reactive mass vaccination with single-dose oral cholera vaccine, Zambia

PubMed Central

Zulu, Gideon; Voute, Caroline; Ferreras, Eva; Muleya, Clara Mbwili; Malama, Kennedy; Pezzoli, Lorenzo; Mufunda, Jacob; Robert, Hugues; Uzzeni, Florent; Luquero, Francisco J; Chizema, Elizabeth; Ciglenecki, Iza

2018-01-01

Abstract Objective To describe the implementation and feasibility of an innovative mass vaccination strategy – based on single-dose oral cholera vaccine – to curb a cholera epidemic in a large urban setting. Method In April 2016, in the early stages of a cholera outbreak in Lusaka, Zambia, the health ministry collaborated with Médecins Sans Frontières and the World Health Organization in organizing a mass vaccination campaign, based on single-dose oral cholera vaccine. Over a period of 17 days, partners mobilized 1700 health ministry staff and community volunteers for community sensitization, social mobilization and vaccination activities in 10 townships. On each day, doses of vaccine were delivered to vaccination sites and administrative coverage was estimated. Findings Overall, vaccination teams administered 424 100 doses of vaccine to an estimated target population of 578 043, resulting in an estimated administrative coverage of 73.4%. After the campaign, few cholera cases were reported and there was no evidence of the disease spreading within the vaccinated areas. The total cost of the campaign – 2.31 United States dollars (US$) per dose – included the relatively low cost of local delivery – US$ 0.41 per dose. Conclusion We found that an early and large-scale targeted reactive campaign using a single-dose oral vaccine, organized in response to a cholera epidemic within a large city, to be feasible and appeared effective. While cholera vaccines remain in short supply, the maximization of the number of vaccines in response to a cholera epidemic, by the use of just one dose per member of an at-risk community, should be considered. PMID:29403111

Vaccine antigen production in transgenic plants: strategies, gene constructs and perspectives.

PubMed

Sala, Francesco; Manuela Rigano, M; Barbante, Alessandra; Basso, Barbara; Walmsley, Amanda M; Castiglione, Stefano

2003-01-30

Stable integration of a gene into the plant nuclear or chloroplast genome can transform higher plants (e.g. tobacco, potato, tomato, banana) into bioreactors for the production of subunit vaccines for oral or parental administration. This can also be achieved by using recombinant plant viruses as transient expression vectors in infected plants. The use of plant-derived vaccines may overcome some of the major problems encountered with traditional vaccination against infectious diseases, autoimmune diseases and tumours. They also offer a convenient tool against the threat of bio-terrorism. State of the art, experimental strategies, safety and perspectives are discussed in this article.

A human papillomavirus type 16 vaccine by oral delivery of L1 protein.

PubMed

Sasagawa, Toshiyuki; Tani, Mayuko; Basha, Walid; Rose, Robert C; Tohda, Hideki; Giga-Hama, Yuko; Azar, Khadijeh K; Yasuda, Hideyo; Sakai, Akemi; Inoue, Masaki

2005-06-01

To establish an edible HPV16 vaccine, we constructed a recombinant HPV16 L1-expressing Schizosaccharomyces pombe yeast strain (HPV16L1 yeast). A preliminary study revealed that freeze-dried yeast cells could be delivered safely, and were digested in the mouse intestine. The freeze-dried HPV16 L1 yeast was administered orally as an edible vaccine, with or without the mucosal adjuvant heat-labile toxin LT (R192G), to 18 female BALB/c mice. After the third immunization, none of the mice that received the edible HPV16 vaccine showed specific antibody responses, whereas all of the positive controls that were administered intranasally with 5 microg of HPV16-virus-like particles (VLP) had serum IgG, and genital IgA and IgG that reacted with HPV16-VLP in enzyme-linked immunosorbent assays (ELISAs). When a suboptimal dose (1 microg) of HPV16-VLP was administered to all the mice, including the negative control mice, 50% of the mice that were pre-immunized with the edible HPV16 vaccine showed positive serum IgG responses, while none of the negative controls showed any response. Vaginal IgG and IgA antibodies were also elicited in 33 and 39%, respectively, of the mice that were given with the edible HPV16 vaccine and the intranasal boost. All of the antibodies reacted more strongly to intact HPV16-VLP than to denatured HPV16-L1 protein suggesting that the edible vaccine primes for antibody responses against conformation-dependent epitopes. The inclusion of adjuvant in the vaccine formulation marginally increased the genital IgA response (P=0.06). HPV16-L1 protein in the yeast might induce tolerance in the vaccinated animals that could be recovered by intranasal boosting with a suboptimal dose of HPV-VLP. This freeze-dried yeast system may be useful as an oral delivery of HPV 16 L1 protein.

Increasing Childhood Influenza Vaccination

PubMed Central

Nowalk, Mary Patricia; Lin, Chyongchiou J.; Hannibal, Kristin; Reis, Evelyn C.; Gallik, Gregory; Moehling, Krissy K.; Huang, Hsin-Hui; Allred, Norma J.; Wolfson, David H.; Zimmerman, Richard K.

2014-01-01

Background Since the 2008 inception of universal childhood influenza vaccination, national rates have risen more dramatically among younger children than older children and reported rates across racial/ethnic groups are inconsistent. Interventions may be needed to address age and racial disparities to achieve the recommended childhood influenza vaccination target of 70%. Purpose To evaluate an intervention to increase childhood influenza vaccination across age and racial groups. Methods In 2011–2012, 20 primary care practices treating children were randomly assigned to Intervention and Control arms of a cluster randomized controlled trial to increase childhood influenza vaccination uptake using a toolkit and other strategies including early delivery of donated vaccine, in-service staff meetings, and publicity. Results The average vaccination differences from pre-intervention to the intervention year were significantly larger in the Intervention arm (n=10 practices) than the Control arm (n=10 practices), for children aged 2–8 years (10.2 percentage points (pct pts) Intervention vs 3.6 pct pts Control) and 9–18 years (11.1 pct pts Intervention vs 4.3 pct pts Control, p<0.05), for non-white children (16.7 pct pts Intervention vs 4.6 pct pts Control, p<0.001), and overall (9.9 pct pts Intervention vs 4.2 pct pts Control, p<0.01). In multi-level modeling that accounted for person- and practice-level variables and the interactions among age, race and intervention, the likelihood of vaccination increased with younger age group (6–23 months), white race, commercial insurance, the practice’s pre-intervention vaccination rate, and being in the Intervention arm. Estimates of the interaction terms indicated that the intervention increased the likelihood of vaccination for non-white children in all age groups and white children aged 9–18 years. Conclusions A multi-strategy intervention that includes a practice improvement toolkit can significantly improve influenza

Physical and Chemical Strategies for Therapeutic Delivery by Using Polymeric Nanoparticles

PubMed Central

Morachis, José M.; Mahmoud, Enas A.

2012-01-01

A significant challenge that most therapeutic agents face is their inability to be delivered effectively. Nanotechnology offers a solution to allow for safe, high-dose, specific delivery of pharmaceuticals to the target tissue. Nanoparticles composed of biodegradable polymers can be designed and engineered with various layers of complexity to achieve drug targeting that was unimaginable years ago by offering multiple mechanisms to encapsulate and strategically deliver drugs, proteins, nucleic acids, or vaccines while improving their therapeutic index. Targeting of nanoparticles to diseased tissue and cells assumes two strategies: physical and chemical targeting. Physical targeting is a strategy enabled by nanoparticle fabrication techniques. It includes using size, shape, charge, and stiffness among other parameters to influence tissue accumulation, adhesion, and cell uptake. New methods to measure size, shape, and polydispersity will enable this field to grow and more thorough comparisons to be made. Physical targeting can be more economically viable when certain fabrication techniques are used. Chemical targeting can employ molecular recognition units to decorate the surface of particles or molecular units responsive to diseased environments or remote stimuli. In this review, we describe sophisticated nanoparticles designed for tissue-specific chemical targeting that use conjugation chemistry to attach targeting moieties. Furthermore, we describe chemical targeting using stimuli responsive nanoparticles that can respond to changes in pH, heat, and light. PMID:22544864

Barriers to and facilitators of child influenza vaccine - perspectives from parents, teens, marketing and healthcare professionals.

PubMed

Bhat-Schelbert, Kavitha; Lin, Chyongchiou Jeng; Matambanadzo, Annamore; Hannibal, Kristin; Nowalk, Mary Patricia; Zimmerman, Richard K

2012-03-23

The CDC recommends annual influenza vaccination for all children age 6 months and older, yet vaccination rates remain modest. Effective strategies to improve influenza vaccination for children are needed. Eight focus groups with 91 parents, teens, pediatric healthcare staff and providers, and immunization and marketing experts were conducted, audiotaped, transcribed verbatim, and coded based on grounded theory. Three themes emerged: barriers, facilitators, and strategies. Barriers included fear, misinformation, and mistrust, with exacerbation of these barriers attributed to media messages. Many considered influenza vaccination unnecessary and inconvenient, but would accept vaccination if recipients or other family members were considered high risk, if recommended by their doctor or another trusted person, or if offered or mandated by the school. Access to better information regarding influenza disease burden and vaccine safety and efficacy were notable facilitators, as were prevention of the inconvenience of missing work or important events, and if the child requests to receive the vaccine. Marketing strategies included incentives, jingles, videos, wearable items, strategically-located information sheets or posters, and promotion by informed counselors. Practice-based strategies included staff buy-in, standing orders protocols, vaccination clinics, and educational videos. Teen-specific strategies included message delivery through schools, texting, internet, and social networking sites. To improve influenza vaccination rates for children using practice-based interventions, participants suggested campaigns that provide better information regarding the vaccine, the disease and its implications, and convenient access to vaccination. Strategies targeting adolescents should use web-based social marketing technologies and campaigns based in schools. Copyright © 2012 Elsevier Ltd. All rights reserved.

Helicobacter pylori vaccine: from past to future.

PubMed

Agarwal, Kanishtha; Agarwal, Shvetank

2008-02-01

Helicobacter pylori infection is highly prevalent worldwide and is an important cause of gastritis, peptic ulcer disease, gastric mucosa-associated lymphoid tissue lymphoma (MALToma), and gastric adenocarcinoma. Infection is usually acquired during childhood and tends to persist unless treated. Because eradication requires treatment with multidrug regimens, prevention of initial infection by a suitable vaccine is attractive. Although immunization with H pylori protein subunits has been encouraging in animals, similar vaccine trials in humans have shown adjuvant-related adverse effects and only moderate effectiveness. Newer immunization approaches (use of DNA, live vectors, bacterial ghosts, and microspheres) are being developed. Several questions about when and whom to vaccinate will need to be appropriately answered, and a cost-effective vaccine production and delivery strategy will have to be useful for developing countries. For this review, we searched MEDLINE using the Medical Subject Heading (MeSH) terms Helicobacter pylori and vaccines for articles in English from 1990 to 2007.

Access and Attitudes to HPV Vaccination amongst Hard-To-Reach Populations in Kenya

PubMed Central

Watson-Jones, Deborah; Mugo, Nelly; Lees, Shelley; Mathai, Muthoni; Vusha, Sophie; Ndirangu, Gathari; Ross, David A.

2015-01-01

Background Sub-Saharan Africa bears the greatest burden of cervical cancer. Human papillomavirus (HPV) vaccination programmes to prevent the disease will need to reach vulnerable girls who may not be able access health and screening services in the future. We conducted formative research on facilitators and barriers to HPV vaccination and potential acceptability of a future HPV vaccination programme amongst girls living in hard-to-reach populations in Kenya. Methods Stakeholder interviews with Ministry of Health staff explored barriers to and support for the uptake of HPV vaccination. A situation assessment was conducted to assess community services in Maasai nomadic pastoralist communities in Kajiado County and in Korogocho informal settlement in Nairobi city, followed by focus group discussions (n=14) and semi-structured interviews (n=28) with health workers, parents, youth, and community and religious leaders. These covered marriage, knowledge of cervical cancer and HPV, factors that might inhibit or support HPV vaccine uptake and intention to accept HPV vaccine if a programme was in place. Results Reported challenges to an HPV vaccination programme included school absenteeism and drop-out, early age of sex and marriage, lack of parental support, population mobility and distance from services. Despite little prior knowledge of cervical cancer and HPV, communities were interested in receiving HPV vaccination. Adequate social mobilisation and school-based vaccination, supplemented by out-reach activities, were considered important facilitating factors to achieve high coverage. There was some support for a campaign approach to vaccine delivery. Conclusions Given the high level of support for a vaccine against cervical cancer and the experience of reaching pastoralist and slum-dwellers for other immunizations, implementing an HPV vaccine programme should be feasible in such hard-to-reach communities. This may require additional delivery strategies in addition to the

Novel drug delivery strategies for porphyrins and porphyrin precursors

NASA Astrophysics Data System (ADS)

Morrow, D. I. J.; Donnelly, R. F.

2009-06-01

superficial lesions, such as actinic keratosis. In addition, photodynamic antimicrobial chemotherapy (PACT) is attracting increasing interest for the treatment of infection. However, delivery strategies for topical PDT and PACT are still based on application of rather simplistic cream and solution formulations, with little consideration given to thermodynamics, targeting or the physicochemical properties of the active agent. Purpose-designed dosage forms for topical delivery of aminolevulinic acid or its esters include creams containing penetration enhancers and/or iron chelators, pressure sensitive patches and bioadhesive patches. Such systems aim to enhance drug delivery across the stratum corneum and keratinised debris overlying neoplastic lesions and improve subsequent protoporphyrin IX (PpIX) production. The alternative to using porphyrin precursors is the use of pre-formed photosensitisers. However, owing to their relatively high molecular weights, conventional topical application is not appropriate. Innovative strategies, such as the use of needle-free injections and microneedle arrays, bypass the stratum corneum, enabling rapid and targeted delivery not only porphyrin precursors but also pre-formed photosensitisers. This presentation will review drug delivery work published to date in the fields of PDT and PACT. In addition, the benefits of employing the latest advances in pharmaceutical technology will be highlighted.

Financial evaluation of different vaccination strategies for controlling the bluetongue virus serotype 8 epidemic in The Netherlands in 2008.

PubMed

Velthuis, Annet G J; Mourits, Monique C M; Saatkamp, Helmut W; de Koeijer, Aline A; Elbers, Armin R W

2011-05-04

Bluetongue (BT) is a vector-borne disease of ruminants caused by bluetongue virus that is transmitted by biting midges (Culicoides spp.). In 2006, the introduction of BTV serotype 8 (BTV-8) caused a severe epidemic in Western and Central Europe. The principal effective veterinary measure in response to BT was believed to be vaccination accompanied by other measures such as movement restrictions and surveillance. As the number of vaccine doses available at the start of the vaccination campaign was rather uncertain, the Dutch Ministry of Agriculture, Nature and Food Quality and the Dutch agricultural industry wanted to evaluate several different vaccination strategies. This study aimed to rank eight vaccination strategies based on their efficiency (i.e. net costs in relation to prevented losses or benefits) for controlling the bluetongue virus serotype 8 epidemic in 2008. An economic model was developed that included the Dutch professional cattle, sheep and goat sectors together with the hobby farms. Strategies were evaluated based on the least cost - highest benefit frontier, the benefit-cost ratio and the total net returns. Strategy F, where all adult sheep at professional farms in The Netherlands would be vaccinated was very efficient at lowest costs, whereas strategy D, where additional to all adult sheep at professional farms also all adult cattle in the four Northern provinces would be vaccinated, was also very efficient but at a little higher costs. Strategy C, where all adult sheep and cattle at professional farms in the whole of The Netherlands would be vaccinated was also efficient but again at higher costs. This study demonstrates that a financial analysis differentiates between vaccination strategies and indicates important decision rules based on efficiency.

Vaccines to prevent pneumonia in children - a developing country perspective.

PubMed

Oliwa, Jacquie N; Marais, Ben J

2017-03-01

Pneumonia accounted for 15% of the 6.3 million deaths among children younger than five years in 2013, a total of approximately 935,000 deaths worldwide. Routine vaccination against common childhood illnesses has been identified as one of the most cost-effective strategies to prevent death from pneumonia. Vaccine-preventable or potentially preventable diseases commonly linked with respiratory tract infections include Streptococcus pneumoniae, Haemophilus influenza type-b (Hib), pertussis, influenza, measles, and tuberculosis. Although here have been great strides in the development and administration of effective vaccines, the countries that carry the largest disease burdens still struggle to vaccinate their children and newer conjugated vaccines remain out of reach for many. The Global Vaccine Action Plan (GVAP) has identified priority areas for innovation in research in all aspects of immunisation development and delivery to ensure equitable access to vaccines for all. Copyright © 2015 Elsevier Ltd. All rights reserved.

Self-amplifying mRNA vaccines.

PubMed

Brito, Luis A; Kommareddy, Sushma; Maione, Domenico; Uematsu, Yasushi; Giovani, Cinzia; Berlanda Scorza, Francesco; Otten, Gillis R; Yu, Dong; Mandl, Christian W; Mason, Peter W; Dormitzer, Philip R; Ulmer, Jeffrey B; Geall, Andrew J

2015-01-01

This chapter provides a brief introduction to nucleic acid-based vaccines and recent research in developing self-amplifying mRNA vaccines. These vaccines promise the flexibility of plasmid DNA vaccines with enhanced immunogenicity and safety. The key to realizing the full potential of these vaccines is efficient delivery of nucleic acid to the cytoplasm of a cell, where it can amplify and express the encoded antigenic protein. The hydrophilicity and strong net negative charge of RNA impedes cellular uptake. To overcome this limitation, electrostatic complexation with cationic lipids or polymers and physical delivery using electroporation or ballistic particles to improve cellular uptake has been evaluated. This chapter highlights the rapid progress made in using nonviral delivery systems for RNA-based vaccines. Initial preclinical testing of self-amplifying mRNA vaccines has shown nonviral delivery to be capable of producing potent and robust innate and adaptive immune responses in small animals and nonhuman primates. Historically, the prospect of developing mRNA vaccines was uncertain due to concerns of mRNA instability and the feasibility of large-scale manufacturing. Today, these issues are no longer perceived as barriers in the widespread implementation of the technology. Currently, nonamplifying mRNA vaccines are under investigation in human clinical trials and can be produced at a sufficient quantity and quality to meet regulatory requirements. If the encouraging preclinical data with self-amplifying mRNA vaccines are matched by equivalently positive immunogenicity, potency, and tolerability in human trials, this platform could establish nucleic acid vaccines as a versatile new tool for human immunization. Copyright © 2015 Elsevier Inc. All rights reserved.

Vaccine delivery to the oral cavity using coated microneedles induces systemic and mucosal immunity

PubMed Central

Ma, Yunzhe; Tao, Wenqian; Krebs, Shelly J.; Sutton, William F.; Haigwood, Nancy L.; Gill, Harvinder S.

2014-01-01

Purpose The objective of this study is to evaluate the feasibility of using coated microneedles to deliver vaccines into the oral cavity to induce systemic and mucosal immune responses. Method Microneedles were coated with sulforhodamine, ovalbumin and two HIV antigens. Coated microneedles were inserted into the inner lower lip and dorsal surface of the tongue of rabbits. Histology was used to confirm microneedle insertion, and systemic and mucosal immune responses were characterized by measuring antigen-specific immunoglobulin G (IgG) in serum and immunoglobulin A (IgA) in saliva, respectively. Results Histological evaluation of tissues shows that coated microneedles can penetrate the lip and tongue to deliver coatings. Using ovalbumin as a model antigen it was found that the lip and the tongue are equally immunogenic sites for vaccination. Importantly, both sites also induced a significant (p < 0.05) secretory IgA in saliva compared to pre-immune saliva. Microneedle-based oral cavity vaccination was also compared to the intramuscular route using two HIV antigens, a virus-like particle and a DNA vaccine. Microneedle-based delivery to the oral cavity and the intramuscular route exhibited similar (p > 0.05) yet significant (p < 0.05) levels of antigen-specific IgG in serum. However, only the microneedle-based oral cavity vaccination group stimulated a significantly higher (p < 0.05) antigen-specific IgA response in saliva, but not intramuscular injection. Conclusion In conclusion, this study provides a novel method using microneedles to induce systemic IgG and secretory IgA in saliva, and could offer a versatile technique for oral mucosal vaccination. PMID:24623480

Chlamydia vaccine candidates and tools for chlamydial antigen discovery.

PubMed

Rockey, Daniel D; Wang, Jie; Lei, Lei; Zhong, Guangming

2009-10-01

The failure of the inactivated Chlamydia-based vaccine trials in the 1960s has led researchers studying Chlamydia to take cautious and rational approaches to develop safe and effective chlamydial vaccines. Subsequent research efforts focused on three areas. The first is the analysis of the immunobiology of chlamydial infection in animal models, with supporting clinical studies, to identify the immune correlates of both protective immunity and pathological responses. Second, recent radical improvements in genomics, proteomics and associated technologies have assisted in the implementation of creative approaches to search for suitable vaccine candidates. Third, progress in the analysis of host response and adjuvanticity regulating both innate and adaptive immunity at the mucosal site of infection has led to progress in the design of optimal delivery and adjuvant systems for enhancing protective immunity. Considerable progress has been made in the first two areas but research efforts to better define the factors that regulate immunity at mucosal sites of infection and to develop strategies to boost protective immunity via immunomodulation, effective delivery systems and potent adjuvants, have remained elusive. In this article, we will summarize progress in these areas with a focus on chlamydial vaccine antigen discovery, and discuss future directions towards the development of a safe and effective chlamydial vaccine.

[Influenza vaccination. Effectiveness of current vaccines and future challenges].

PubMed

Ortiz de Lejarazu, Raúl; Tamames, Sonia

2015-01-01

Seasonal influenza is an annual challenge for health-care systems, due to factors such as co-circulation of 2 influenza A subtypes jointly with 2 influenza B lineages; the antigenic drift of these virus, which eludes natural immunity, as well as immunity conferred by vaccination; together with influenza impact in terms of morbidity and mortality. Influenza vaccines have been available for more than 70 years and they have progressed in formulation, production and delivery route. Recommendations on vaccination are focused on those with a higher probability of severe disease, and have a progressively wider coverage, and classically based on inactivated vaccines, but with an increasing importance of attenuated live vaccines. More inactivated vaccines are becoming available, from adyuvanted and virosomal vaccines to intradermal delivery, cell-culture or quadrivalent. Overall vaccine effectiveness is about 65%, but varies depending on characteristics of vaccines, virus, population and the outcomes to be prevented, and ranges from less than 10% to almost 90%. Future challenges are formulations that confer more extensive and lasting protection, as well as increased vaccination coverage, especially in groups such as pregnant women and health-care professionals, as well as being extended to paediatrics. Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

DNA vaccination for cervical cancer; a novel technology platform of RALA mediated gene delivery via polymeric microneedles.

PubMed

Ali, Ahlam A; McCrudden, Cian M; McCaffrey, Joanne; McBride, John W; Cole, Grace; Dunne, Nicholas J; Robson, Tracy; Kissenpfennig, Adrien; Donnelly, Ryan F; McCarthy, Helen O

2017-04-01

HPV subtypes (16, 18) are associated with the development of cervical cancer, with oncoproteins E6 and E7 responsible for pathogenesis. The goal of this study was to evaluate our 'smart system' technology platform for DNA vaccination against cervical cancer. The vaccination platform brings together two main components; a peptide RALA which condenses DNA into cationic nanoparticles (NPs), and a polymeric polyvinylpyrrolidone (PVP) microneedle (MN) patch for cutaneous delivery of the loaded NPs. RALA condensed E6/E7 DNA into NPs not exceeding 100nm in diameter, and afforded the DNA protection from degradation in PVP. Sera from mice vaccinated with MN/RALA-E6/E7 were richer in E6/E7-specific IgGs, displayed a greater T-cell-mediated TC-1 cytotoxicity and contained more IFN-γ than sera from mice that received NPs intramuscularly. More importantly, MN/RALA-E6/E7 delayed TC-1 tumor initiation in a prophylactic model, and slowed tumor growth in a therapeutic model of vaccination, and was more potent than intramuscular vaccination. Copyright © 2016 Elsevier Inc. All rights reserved.

Current therapeutic vaccination and immunotherapy strategies for HPV-related diseases

PubMed Central

Skeate, Joseph G.; Woodham, Andrew W.; Einstein, Mark H.; Da Silva, Diane M.; Kast, W. Martin

2016-01-01

ABSTRACT Carcinomas of the anogenital tract, in particular cervical cancer, remains one of the most common cancers in women, and represent the most frequent gynecological malignancies and the fourth leading cause of cancer death in women worldwide. Human papillomavirus (HPV)-induced lesions are immunologically distinct in that they express viral antigens, which are necessary to maintain the cancerous phenotype. The causal relationship between HPV infection and anogenital cancer has prompted substantial interest in the development of therapeutic vaccines against high-risk HPV types targeting the viral oncoproteins E6 and E7. This review will focus on the most recent clinical trials for immunotherapies for mucosal HPV-induced lesions as well as emerging therapeutic strategies that have been tested in pre-clinical models for HPV-induced diseases. Progress in peptide- and protein-based vaccines, DNA-based vaccines, viral/bacterial vector-based vaccines, immune checkpoint inhibition, immune response modifiers, and adoptive cell therapy for HPV will be discussed. PMID:26835746

Current therapeutic vaccination and immunotherapy strategies for HPV-related diseases.

PubMed

Skeate, Joseph G; Woodham, Andrew W; Einstein, Mark H; Da Silva, Diane M; Kast, W Martin

2016-06-02

Carcinomas of the anogenital tract, in particular cervical cancer, remains one of the most common cancers in women, and represent the most frequent gynecological malignancies and the fourth leading cause of cancer death in women worldwide. Human papillomavirus (HPV)-induced lesions are immunologically distinct in that they express viral antigens, which are necessary to maintain the cancerous phenotype. The causal relationship between HPV infection and anogenital cancer has prompted substantial interest in the development of therapeutic vaccines against high-risk HPV types targeting the viral oncoproteins E6 and E7. This review will focus on the most recent clinical trials for immunotherapies for mucosal HPV-induced lesions as well as emerging therapeutic strategies that have been tested in pre-clinical models for HPV-induced diseases. Progress in peptide- and protein-based vaccines, DNA-based vaccines, viral/bacterial vector-based vaccines, immune checkpoint inhibition, immune response modifiers, and adoptive cell therapy for HPV will be discussed.

Exosomes Enter Vaccine Development: Strategies Meeting Global Challenges of Emerging Infections.

PubMed

Jungbauer, Alois

2018-04-01

New approaches for vaccination must be developed in order to meet the grand challenges for emerging infectious diseases. Exosomes now enter vaccine development and these are strategies are meeting these global challenges, as demonstrated by Anticoli et al., in this issue of Biotechnology Journal. Using exosome vaccines has been now been demonstrated in vivo for several viruses such as Ebola Virus VP24, VP40, and NP, Influenza Virus NP, Crimean-Congo Hemorrhagic Fever NP, West Nile Virus NS3, and Hepatitis C Virus NS3. Now this technology must be tested in clinics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.