Vaccine
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From August to December 2011, a multidisciplinary group with expertise in mathematical modeling was constituted by the GAVI Alliance and the Bill & Melinda Gates Foundation to estimate the impact of vaccination in 73 countries supported by the GAVI Alliance. ⋯ Vaccination of persons during 2011-2020 in 73 GAVI-eligible countries is expected to have substantial public health impact, particularly in Africa and Southeast Asia, two regions with high mortality. The actual impact of vaccination in these countries may be higher than our estimates because several widely used antigens were not included in the analysis. The quality of our estimates is limited by lack of data on underlying disease burden and vaccine effectiveness against fatal disease outcomes in developing countries. We plan to update the estimates annually to reflect updated demand forecasts, to refine model assumptions based on results of new information, and to extend the analysis to include morbidity and economic benefits.
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We aimed to determine demographic predictors of parental vaccine safety and risk perceptions, and assess the relationship between the occurrence of children's perceived adverse events following immunisation (AEFI) on parents' opinions. ⋯ Parents commonly perceive and report that their child has experienced an AEFI. In this group of parents the subsequent expectation of an AEFI and vaccine safety concerns may be heightened. Further research should investigate parental understandings of differentiating an expected event from an adverse event as this could inform immunization risk communication and consumer AEFI reporting strategies.
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The Global Alliance for Vaccines and Immunization (GAVI) is a public-private global health partnership aiming to increase access to immunisation in poor countries. The Democratic Republic of the Congo (DRC) is the third largest recipient of GAVI funds in terms of cumulative disbursed support. We provided a comprehensive assessment of GAVI support and analysed trends in immunisation performance and financing in the DRC from 2002 to 2010. ⋯ GAVI support to DRC has enhanced significant progress in routine immunisation performance and financing during 2002-2010. Although progress has been partly sustained, the initial observed increase in DTP3 coverage and available funding for routine immunisation halted towards the end of the analysis period, coinciding with tetravalent and pentavalent vaccine introduction. These findings highlight the need for additional efforts to ensure the sustainability of routine immunization program performance and financing.
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Epitopes of the circumsporozoite (CS) protein of Plasmodium falciparum, the most pathogenic species of the malaria parasite, have been shown to elicit protective immunity in experimental animals and human volunteers. The mechanisms of immunity include parasite-neutralizing antibodies that can inhibit parasite motility in the skin at the site of infection and in the bloodstream during transit to the hepatocyte host cell and also block interaction with host cell receptors on hepatocytes. In addition, specific CD4+ and CD8+ cellular mechanisms target the intracellular hepatic forms, thus preventing release of erythrocytic stage parasites from the infected hepatocyte and the ensuing blood stage cycle responsible for clinical disease. ⋯ In addition, mice immunized with microparticles bearing only T-cell epitopes were not protected, demonstrating that cellular immunity alone was not sufficient for protective immunity. Although the microparticles without adjuvant were immunogenic and protective, a simple modification with the lipopeptide TLR2 agonist Pam3Cys increased the potency and efficacy of the LbL vaccine candidate. This study demonstrates the potential of LbL particles as promising malaria vaccine candidates using the T1BT epitopes from the P. falciparum CS protein.
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Deterministic dynamic compartmental transmission models (DDCTMs) of human papillomavirus (HPV) transmission have been used in a number of studies to estimate the potential impact of HPV vaccination programs. In most cases, the models were built under the assumption that an individual who cleared HPV infection develops (life-long) natural immunity against re-infection with the same HPV type (this is known as SIR scenario). This assumption was also made by two Australian modelling studies evaluating the impact of the National HPV Vaccination Program to assist in the health-economic assessment of male vaccination. ⋯ We observed that for non-SIR models the herd immunity effect measured in relative reductions in HPV prevalence in the unvaccinated population was much more pronounced than for the SIR model. For example, with vaccine efficacy of 95% for females and 90% for males, the reductions for HPV-16 were 3% in females and 28% in males for the SIR model, and at least 30% (females) and 60% (males) for non-SIR models. The magnitude of these differences implies that evaluations of the impact of vaccination programs using DDCTMs should incorporate several model structures until our understanding of natural immunity is improved.