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Feikin D.R.,International Vaccine Access Center | Feikin D.R.,Centers for Disease Control and Prevention | Scott J.A.G.,Wellcome Trust Research Programme | Scott J.A.G.,London School of Hygiene and Tropical Medicine | Gessner B.D.,Voltaire
The Lancet | Year: 2014

Vaccine probe studies have emerged in the past 15 years as a useful way to characterise disease. By contrast, traditional studies of vaccines focus on defining the vaccine effectiveness or efficacy. The underlying basis for the vaccine probe approach is that the difference in disease burden between vaccinated and unvaccinated individuals can be ascribed to the vaccine-specific pathogen. Vaccine probe studies can increase understanding of a vaccine's public health value. For instance, even when a vaccine has a seemingly low efficacy, a high baseline disease incidence can lead to a large vaccine-preventable disease burden and thus that population-based vaccine introduction would be justified. So far, vaccines have been used as probes to characterise disease syndromes caused by Haemophilus influenzae type b, pneumococcus, rotavirus, and early infant influenza. However, vaccine probe studies have enormous potential and could be used more widely in epidemiology, for example, to define the vaccine-preventable burden of malaria, typhoid, paediatric influenza, and dengue, and to identify causal interactions between different pathogens. Source


McIntyre P.B.,University of Sydney | O'Brien K.L.,International Vaccine Access Center | Greenwood B.,London School of Hygiene and Tropical Medicine | Van De Beek D.,University of Amsterdam
The Lancet | Year: 2012

Three bacteria-Haemophilus infl uenzae, Streptococcus pneumoniae, and Neisseria meningitidis-account for most acute bacterial meningitis. Measurement of the eff ect of protein-polysaccharide conjugate vaccines is most reliable for H infl uenzae meningitis because one serotype and one age group account for more than 90% of cases and the incidence has been best measured in high-income countries where these vaccines have been used longest. Pneumococcal and meningococcal meningitis are caused by diverse serotypes and have a wide age distribution; measurement of their incidence is complicated by epidemics and scarcity of surveillance, especially in low-income countries. Near elimination of H infl uenzae meningitis has been documented after vaccine introduction. Despite greater than 90% reductions in disease attributable to vaccine serotypes, all-age pneumococcal meningitis has decreased by around 25%, with little data from low-income settings. Near elimination of serogroup C meningococcal meningitis has been documented in several high-income countries, boding well for the eff ect of a new serogroup A meningococcal conjugate vaccine in the African meningitis belt. Source


Levine O.S.,International Vaccine Access Center | Bloom D.E.,Harvard University | Cherian T.,Immunizations | De Quadros C.,Sabin Institute | And 4 more authors.
The Lancet | Year: 2011

Vaccines have already saved many lives and they have the potential to save many more as increasingly elaborate technologies deliver new and effective vaccines against both infectious diseases - for which there are currently no effective licensed vaccines - such as malaria, tuberculosis, and HIV and non-infectious diseases such as hypertension and diabetes. However, these new vaccines are likely to be more complex and expensive than those that have been used so effectively in the past, and they could have a multifaceted effect on the disease that they are designed to prevent, as has already been seen with pneumococcal conjugate vaccines. Deciding which new vaccines a country should invest in requires not only sound advice from international organisations such as WHO but also a well informed national immunisation advisory committee with access to appropriate data for local disease burden. Introduction of vaccines might need modification of immunisation schedules and delivery procedures. Novel methods are needed to finance the increasing number of new vaccines that have the potential to save lives in countries that are too poor to afford them. Here, we discuss some options. © 2011 Elsevier Ltd. Source


Levine O.,International Vaccine Access Center
American Journal of Public Health | Year: 2012

For the influenza pandemic of 2009-2010, countries responded to the direct threat of influenza but may have missed opportunities and strategies to limit secondary pneumococcal infections. Delivering both vaccines together can potentially increase pneumococcal polysaccharide vaccine (PPV23) immunization rates and prevent additional hospitalizations and mortality in the elderly and other highrisk groups. We used PubMed to review the literature on the concomitant use of PPV23 with seasonal influenza vaccines. Eight of 9 clinical studies found that a concomitant program conferred clinical benefits. The 2 studies that compared the cost-effectiveness of different strategies found concomitant immunization to be more cost-effective than either vaccine given alone. Policymakers should consider a stepwise strategy to reduce the burden of secondary pneumococcal infections during seasonal and pandemic influenza outbreaks. Source


Constenla D.O.,International Vaccine Access Center
Revista Panamericana de Salud Publica/Pan American Journal of Public Health | Year: 2015

Objective. A decision-analytic model was constructed to evaluate the economic impact of post-introduction pneumococcal conjugate vaccine (PCV) programs in Ecuador, Honduras, and Paraguay from the societal perspective. Methods. Hypothetical birth cohorts were followed for a 20-year period in each country. Estimates of disease burden, vaccine effectiveness, and health care costs were derived from primary and secondary data sources. Costs were expressed in 2014 US$. Sensitivity analyses were performed to assess the impact of model input uncertainties. Results. Over the 20 years of vaccine program implementation, the health care costs per case ranged from US$ 764 854 to more than US$ 1 million. Vaccination prevented more than 50% of pneumococcal cases and deaths per country. At a cost of US$ 16 per dose, the cost per disability-adjusted life year (DALY) averted for the 10-valent PCV (PCV10) and the 13-valet PCV (PCV13) ranged from US$ 796 (Honduras) to US$ 1 340 (Ecuador) and from US$ 691 (Honduras) to US$ 1 166 (Ecuador) respectively. At a reduced price (US$ 7 per dose), the cost per DALY averted ranged from US$ 327 (Honduras) to US$ 528 (Ecuador) and from US$ 281 (Honduras) to US$ 456 (Ecuador) for PCV10 and PCV13 respectively. Several model parameters influenced the results of the analysis, including vaccine price, vaccine efficacy, disease incidence, and costs. Conclusions. The economic impact of post-introduction PCV needs to be assessed in a context of uncertainty regarding changing antibiotic resistance, herd and serotype replacement effects, differential vaccine prices, and government budget constraints. Source

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