Albert B Sabin Vaccine Institute

Washington, DC, United States

Albert B Sabin Vaccine Institute

Washington, DC, United States
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Gazzinelli M.F.,Federal University of Minas Gerais | Lobato L.,Federal University of Minas Gerais | Matoso L.,Federal University of Minas Gerais | Avila R.,Federal University of Minas Gerais | And 5 more authors.
PLoS Neglected Tropical Diseases | Year: 2010

Background: Obtaining informed consent for clinical trials is especially challenging when working in rural, resource-limited areas, where there are often high levels of illiteracy and lack of experience with clinical research. Such an area, a remote field site in the northeastern part of the state of Minas Gerais, Brazil, is currently being prepared for clinical trials of experimental hookworm vaccines. This study was conducted to assess whether special educational tools can be developed to increase the knowledge and comprehension of potential clinical trial participants and thereby enable them to make truly informed decisions to participate in such research. Methodology/Principal Findings: An informational video was produced to explain the work of the research team and the first planned hookworm vaccine trial, using a pedagogical method based on analogies. Seventy-two adults living in a rural community of Minas Gerais were administered a structured questionnaire that assessed their knowledge of hookworm, of research and of the planned hookworm vaccine trial, as well as their attitudes and perceptions about the researchers and participation in future vaccine trials. The questionnaire was administered before being shown the educational video and two months after and the results compared. After viewing the video, significant improvements in knowledge related to hookworm infection and its health impact were observed: using a composite score combining related questions for which correct answers were assigned a value of 1 and incorrect answers a value of 0, participants had a mean score of 0.76 postvideo compared to 0.68 pre-video (p = 0.0001). Similar improvements were seen in understanding the purpose of vaccination and the possible adverse effects of an experimental vaccine. Although 100% of participants expressed a positive opinion of the researchers even before viewing the film and over 90% said that they would participate in a hookworm vaccine trial, an increase in the number who expressed fear of being vaccinated with a novel vaccine was seen after viewing the video (51.4% post-video versus 29.2% pre-video). Increases were also seen in the proportion who thought that participation in a vaccine trial would be inconvenient or disrupt their daily activities. Conclusions/Significance: Even in rural, resource-limited populations, educational tools can be specially designed that significantly improve understanding and therefore the likelihood of obtaining truly informed consent for participation in clinical research. The observed changes in the knowledge and perceptions of the research participants about hookworm infection and the experimental hookworm vaccine demonstrate that the video intervention was successful in increasing understanding and that the subjects acquired knowledge pertinent to the planned research. © 2010 Gazzinelli et al.


Diemert D.J.,Albert B Sabin Vaccine Institute | Diemert D.J.,George Washington University | Jariwala A.,Albert B Sabin Vaccine Institute | Santiago H.,George Washington University | And 8 more authors.
Journal of Allergy and Clinical Immunology | Year: 2012

Background: Necator americanus Ancylostoma-secreted protein 2 (Na-ASP-2) is secreted by infective hookworm larvae on entry into human hosts. Vaccination of laboratory animals with recombinant Na-ASP-2 provides significant protection against challenge infections. In endemic areas antibodies to Na-ASP-2 are associated with reduced risk of heavy N americanus infections. Objective: To assess the safety and immunogenicity of recombinant Na-ASP-2 adjuvanted with Alhydrogel in healthy Brazilian adults previously infected with N americanus. Methods: Participants were randomized to receive Na-ASP-2 or hepatitis B vaccine. Major IgG and IgE epitopes of the Na-ASP-2 molecule were mapped by using sera from these same subjects. Seroepidemiologic studies in adults and children residing in hookworm-endemic areas were conducted to assess the prevalence of IgE responses to Na-ASP-2. Results: Vaccination with a single dose of Na-ASP-2 resulted in generalized urticarial reactions in several volunteers. These reactions were associated with pre-existing Na-ASP-2-specific IgE likely induced by previous hookworm infection. Surveys revealed that a significant proportion of the population in hookworm-endemic areas had increased levels of IgE to Na-ASP-2. Epitope mapping demonstrated sites on the Na-ASP-2 molecule that are uniquely or jointly recognized by IgG and IgE antibodies. Conclusion: Infection with N americanus induces increased levels of total and specific IgE to Na-ASP-2 that result in generalized urticaria on vaccination with recombinant Na-ASP-2. These data advance knowledge of vaccine development for helminths given their propensity to induce strong T H2 responses. Study data highlight the important differences between the immune responses to natural helminth infection and to vaccination with a recombinant helminth antigen. © 2012 American Academy of Allergy, Asthma & Immunology.


Clements C.J.,University of Melbourne | Watkins M.,Centers for Disease Control and Prevention | de Quadros C.,Albert B Sabin Vaccine Institute | Biellik R.,Consultant Epidemiologist | And 6 more authors.
Vaccine | Year: 2011

Background: The Expanded Programme on Immunization (EPI), launched in 1974, has developed and implemented a range of strategies and practices over the last three decades to ensure that children and adults receive the vaccines they need to help protect them against vaccine-preventable diseases. Many of these strategies have been implemented, resulting in immunization coverage exceeding 80% among children one year of age in many countries. Yet millions of infants remain under-immunized or unimmunized, particularly in poorer countries. In November 2009, a panel of external experts met at the United States Centers for Disease Control and Prevention (CDC) to review and identify areas of research required to strengthen routine service delivery in developing countries. Methods: Research opportunities were identified utilizing presentations emphasizing existing research, gaps in knowledge and key questions. Panel members prioritized the topics, as did other meeting participants. Findings: Several hundred research topics covering a wide range were identified by the panel members and participants. However there were relatively few topics for which there was a consensus that immediate investment in research is warranted. The panel identified 28 topics as priorities. 18 topics were identified as priorities by at least 50% of non-panel participants; of these, five were also identified as priorities by the panel. Research needs included identifying the best ways to increase coverage with existing vaccines and introduce new vaccines, integrate other services with immunizations, and finance immunization programmes. Interpretation: There is an enormous range of research that could be undertaken to support routine immunization. However, implementation of strategic plans, rather than additional research will have the greatest impact on raising immunization coverage and preventing disease, disability, and death from vaccine-preventable diseases. The panel emphasized the importance of tying operational research to programmatic needs, with a focus on efforts to scale up proven best practices in each country, facilitating the full implementation of immunization strategies. © 2011.


Jariwala A.R.,Albert B Sabin Vaccine Institute | Oliveira L.M.,George Washington University | Diemert D.J.,Albert B Sabin Vaccine Institute | Diemert D.J.,George Washington University | And 8 more authors.
Expert Review of Vaccines | Year: 2010

Over the next decade, a new generation of vaccines will target the neglected tropical diseases (NTDs). The goal of most NTD vaccines will be to reduce the morbidity and decrease the chronic debilitating nature of these often-forgotten infections - outcomes that are hard to measure in the traditional potency testing paradigm. The absence of measurable correlates of protection, a lack of permissive animal models for lethal infection, and a lack of clinical indications that do not include the induction of sterilizing immunity required us to reconsider the traditional bioassay methods for determining vaccine potency. Owing to these limitations, potency assay design for NTD vaccines will increasingly rely on a paradigm where potency testing is one among many tools to ensure that a manufacturing process yields a product of consistent quality. Herein, we discuss the evolution of our thinking regarding the design of a potency assay along these newly defined lines and its application to the release of the experimental Necator americanus-glutathione-S- transferase-1 (Na-GST-1) vaccine to prevent human hookworm infection. We discuss the necessary steps to accomplish the design and implementation of such a new potency assay as a resource for the burgeoning NTD vaccine community. Our experience is that much of the existing information is proprietary and needs to be pulled together in a single source to aid in our overall understanding of potency testing. © 2010 Expert Reviews Ltd.


de Quadros C.A.,Albert B Sabin Vaccine Institute
Vaccine | Year: 2011

The smallpox eradication campaign operated in Ethiopia from 1970 until 1977. During this time Ethiopia had only 84 hospitals, 64 health centres and fewer than 400 physicians in a country of 25 million people. In 1970 smallpox vaccination was relatively unknown in the country, and the government actually contested the fact that smallpox was present in the country. Most of the resources of the Ministry of Health were used for malaria eradication. Initial pessimism from the Ministry of Health and others was eventually overcome as the smallpox eradication campaign continued to pick up steam but many remained unenthusiastic. Ethiopia was the first country in the world to start its smallpox eradication campaign from day one with the strategy of "Surveillance and Containment" Establishing a surveillance system in a country with a limited health infrastructure was a daunting challenge. At the end of the first year of the programme in 1971, 26,000 cases of smallpox had been registered through the growing surveillance system. Throughout revolution of 1974 the smallpox campaign was the only UN program to operate in the country; in fact it expanded with the hire of many locals leading to a "nationalized" program. This development ushered in the most successful final phase of the program. As the program progressed cases were diminishing in most regions, however transmission continued in the Ogaden desert. Over the course of the campaign approximately 14.3 million US dollars was spent. Working conditions were extremely challenging and a variety of chiefs, guerrillas, landowners and governments had to be appeased. The programme was successful due to the dedicated national and international staff on the ground and by having the full support of the WHO HQ in Geneva. © 2011 Elsevier Ltd.


PubMed | Albert B Sabin Vaccine Institute
Type: | Journal: Vaccine | Year: 2012

The smallpox eradication campaign operated in Ethiopia from 1970 until 1977. During this time Ethiopia had only 84 hospitals, 64 health centres and fewer than 400 physicians in a country of 25 million people. In 1970 smallpox vaccination was relatively unknown in the country, and the government actually contested the fact that smallpox was present in the country. Most of the resources of the Ministry of Health were used for malaria eradication. Initial pessimism from the Ministry of Health and others was eventually overcome as the smallpox eradication campaign continued to pick up steam but many remained unenthusiastic. Ethiopia was the first country in the world to start its smallpox eradication campaign from day one with the strategy of Surveillance and Containment. Establishing a surveillance system in a country with a limited health infrastructure was a daunting challenge. At the end of the first year of the programme in 1971, 26,000 cases of smallpox had been registered through the growing surveillance system. Throughout revolution of 1974 the smallpox campaign was the only UN program to operate in the country; in fact it expanded with the hire of many locals leading to a nationalized program. This development ushered in the most successful final phase of the program. As the program progressed cases were diminishing in most regions, however transmission continued in the Ogaden desert. Over the course of the campaign approximately 14.3 million US dollars was spent. Working conditions were extremely challenging and a variety of chiefs, guerrillas, landowners and governments had to be appeased. The programme was successful due to the dedicated national and international staff on the ground and by having the full support of the WHO HQ in Geneva.


PubMed | Albert B Sabin Vaccine Institute
Type: Clinical Trial, Phase I | Journal: The Journal of allergy and clinical immunology | Year: 2012

Necator americanus Ancylostoma-secreted protein 2 (Na-ASP-2) is secreted by infective hookworm larvae on entry into human hosts. Vaccination of laboratory animals with recombinant Na-ASP-2 provides significant protection against challenge infections. In endemic areas antibodies to Na-ASP-2 are associated with reduced risk of heavy N americanus infections.To assess the safety and immunogenicity of recombinant Na-ASP-2 adjuvanted with Alhydrogel in healthy Brazilian adults previously infected with N americanus.Participants were randomized to receive Na-ASP-2 or hepatitis B vaccine. Major IgG and IgE epitopes of the Na-ASP-2 molecule were mapped by using sera from these same subjects. Seroepidemiologic studies in adults and children residing in hookworm-endemic areas were conducted to assess the prevalence of IgE responses to Na-ASP-2.Vaccination with a single dose of Na-ASP-2 resulted in generalized urticarial reactions in several volunteers. These reactions were associated with pre-existing Na-ASP-2-specific IgE likely induced by previous hookworm infection. Surveys revealed that a significant proportion of the population in hookworm-endemic areas had increased levels of IgE to Na-ASP-2. Epitope mapping demonstrated sites on the Na-ASP-2 molecule that are uniquely or jointly recognized by IgG and IgE antibodies.Infection with N americanus induces increased levels of total and specific IgE to Na-ASP-2 that result in generalized urticaria on vaccination with recombinant Na-ASP-2. These data advance knowledge of vaccine development for helminths given their propensity to induce strong T(H)2 responses. Study data highlight the important differences between the immune responses to natural helminth infection and to vaccination with a recombinant helminth antigen.

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