Vaccine
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Dengue vaccine development has reached a major milestone with the initiation, in 2010, of the first phase III clinical trial to investigate the Sanofi Pasteur CYD tetravalent dengue vaccine (TDV). The CYD TDV candidate is composed of four recombinant, live, attenuated vaccines (CYD-1-4) based on a yellow fever vaccine 17D (YFV 17D) backbone, each expressing the pre-membrane and envelope genes of one of the four dengue virus serotypes. The vaccine is genetically and phenotypically stable, non-hepatotropic, less neurovirulent than YFV 17D, and does not infect mosquitoes by the oral route. ⋯ The observed level and nature of the cellular immune responses in humans are consistent with the good safety and immunogenicity profile of the vaccine. Preliminary results of an ongoing, proof-of-concept efficacy and large scale safety study in Thai children are expected by the end of 2012. Here we discuss the different steps and challenges of developing CYD TDV, from research to industrialization, and summarize some of the challenges to the successful introduction of a dengue vaccine into immunization programs.
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Should a highly pathogenic avian influenza virus, such as the H5N1 virus type currently circulating in birds, become transmissible among humans, an effective vaccine, rapidly available in vast quantities, would be the best tool to prevent high case-fatalities and the breakdown of health and social services. The number of vaccine doses that could be produced on demand has risen sharply over the last few years; however, it is still alarmingly short of the 13 billion doses that would be needed if two doses were required to protect fully the world's population. Most developing countries would be last in the queue to benefit from a pandemic vaccine. ⋯ To this end, the influenza vaccine technology transfer initiative was launched in 2007 and, to date, vaccine manufacturers in 11 developing countries have received grants to acquire the capacity to produce inactivated or live attenuated influenza vaccine for their populations. In addition, a centralized 'hub' has been established to facilitate training in the new technologies for scientists and regulators in the countries. This supplement of Vaccine is devoted to showcasing the interim results of the WHO initiative and the impressive progress made by the developing country manufacturers.
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To identify the rate of serious adverse events attributable to yellow fever vaccination with 17D and 17DD strains reported in active and passive surveillance data. ⋯ The databases in each country used different definitions, protocols, surveillance mechanisms for the initial identification and reporting of cases, and strategies for the clinical and laboratory follow up of cases. The pharmacovigilance databases provide three sets of estimates: a low estimate from the Brazilian and Australian data, a medium estimate from the US VAERS data, and a higher estimate from the UK and Swiss data. The estimates from the active surveillance data are lower (and strongly influenced by the Brazilian data) and the estimates from the passive surveillance studies are also lower (strongly influenced by the London Hospital for Tropical Diseases data from the early 1950s). Sophisticated pathology, histopathology and tests such as PCR amplicon sequencing are needed to prove that serious adverse events were actually caused by the yellow fever vaccine, and the availability of such diagnostic capability is strongly biased towards recent reports from developed countries. Despite these variations in the estimation of serious harm, overall the 17D and 17DD yellow fever vaccine has proven to be a very safe vaccine and is highly effective against an illness with high potential mortality rates.
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To identify the rate of serious adverse events attributable to yellow fever vaccination with 17D and 17DD strains reported in active and passive surveillance data. ⋯ The databases in each country used different definitions, protocols, surveillance mechanisms for the initial identification and reporting of cases, and strategies for the clinical and laboratory follow up of cases. The pharmacovigilance databases provide three sets of estimates: a low estimate from the Brazilian and Australian data, a medium estimate from the US VAERS data, and a higher estimate from the UK and Swiss data. The estimates from the active surveillance data are lower (and strongly influenced by the Brazilian data) and the estimates from the passive surveillance studies are also lower (strongly influenced by the London Hospital for Tropical Diseases data from the early 1950s). Sophisticated pathology, histopathology and tests such as PCR amplicon sequencing are needed to prove that serious adverse events were actually caused by the yellow fever vaccine, and the availability of such diagnostic capability is strongly biased towards recent reports from developed countries. Despite these variations in the estimation of serious harm, overall the 17D and 17DD yellow fever vaccine has proven to be a very safe vaccine and is highly effective against an illness with high potential mortality rates.
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As A(H1N1) influenza enters the post-pandemic phase, health authorities around the world are reviewing the response to the pandemic. To ensure this process enhances future preparations, it is essential that perspectives are included from all relevant stakeholders, including vaccine manufacturers. This paper outlines the contribution of R&D-based influenza vaccine producers to the pandemic response, and explores lessons that can be learned to improve future preparedness. ⋯ Enhancing international regulatory co-operation and mutual recognition of approvals could accelerate vaccine supply, while maintaining safety standards. Strengthening communications with the public and healthcare workers using new approaches and new channels could help improve vaccine uptake. Finally, increasing seasonal vaccine coverage will be particularly important to extend and sustain pandemic vaccine production capacity.