Vaccine
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Test-negative (TN) studies have become the most widely used study design for the estimation of influenza vaccine effectiveness (VE) and are easily incorporated into existing influenza surveillance networks. We seek to determine the bias of TN-based VE estimates during a pandemic using a dynamic probability model. The model is used to evaluate and compare the bias of VE estimates under various sources of bias when vaccination occurs after the beginning of an outbreak, such as during a pandemic. ⋯ VE estimates from TN studies were biased regardless of the source of bias present. However, if the core assumption of the TN design is satisfied, that is, if vaccination does not affect the probability of non-influenza ARI, then TN-based VE estimates against medically-attended influenza will only suffer from small (<0.05) to moderate bias (≥0.05 and <0.10). These results suggest that if sources of bias listed above are ruled out, TN studies are a valid study design for the estimation of VE during a pandemic.
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Changing pneumococcal disease epidemiology due to childhood vaccination has prompted re-examination of US adult pneumococcal vaccination policies, as have considerations of greater pneumococcal disease incidence and higher prevalence of conditions that increase risk in underserved minority populations. Prior analyses suggest routine pneumococcal vaccination at age 50 could be considered, which could disproportionately benefit underserved populations. ⋯ Despite changes in pneumococcal epidemiology, current CDC recommendations were favored in underserved minority and general population cohorts. Polysaccharide vaccine for all 50-year-olds could be considered under some vaccine uptake and effectiveness assumptions, particularly if mitigating racial health disparities in pneumococcal disease is a priority.
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Influenza vaccination during pregnancy is known to prevent severe influenza illness but its effects on other outcomes and the extent to which its safety is affected by timing of vaccination, maternal race/ethnicity and the type of vaccine is less clear. Therefore, we examined this in a large retrospective cohort. ⋯ This study found no evidence of adverse maternal and infant outcomes associated with seasonal influenza vaccine during pregnancy. On the contrary, vaccinated women were less likely to have adverse outcomes than unvaccinated women. The lack of increased adverse outcomes associated with influenza vaccination suggests that the benefits of vaccination during pregnancy to the woman and her child far outweigh any risk, if there is one, from the vaccination.
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The impact of influenza in children under 5 can be severe and fatal. However, the influenza vaccination uptake in China remains suboptimal. The objectives of this study were to investigate parents' perceptions on influenza vaccination and to assess vaccination promotional factors. ⋯ Parents had high intention to get their kindergarten children vaccinated with the influenza vaccine in spite of the low uptake rate. Our results indicate that offering free influenza vaccines and parental education over the next years may increase the influenza vaccination rate.