Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Ridenhour BJ[original query] |
---|
Effectiveness of inactivated influenza vaccines in preventing influenza-associated deaths and hospitalizations among Ontario residents Aged ≥65 years: estimates with generalized linear models accounting for healthy vaccinee effects
Ridenhour BJ , Campitelli MA , Kwong JC , Rosella LC , Armstrong BG , Mangtani P , Calzavara AJ , Shay DK . PLoS One 2013 8 (10) e76318 BACKGROUND: Estimates of the effectiveness of influenza vaccines in older adults may be biased because of difficulties identifying and adjusting for confounders of the vaccine-outcome association. We estimated vaccine effectiveness for prevention of serious influenza complications among older persons by using methods to account for underlying differences in risk for these complications. METHODS: We conducted a retrospective cohort study among Ontario residents aged ≥65 years from September 1993 through September 2008. We linked weekly vaccination, hospitalization, and death records for 1.4 million community-dwelling persons aged ≥65 years. Vaccine effectiveness was estimated by comparing ratios of outcome rates during weeks of high versus low influenza activity (defined by viral surveillance data) among vaccinated and unvaccinated subjects by using log-linear regression models that accounted for temperature and time trends with natural spline functions. Effectiveness was estimated for three influenza-associated outcomes: all-cause deaths, deaths occurring within 30 days of pneumonia/influenza hospitalizations, and pneumonia/influenza hospitalizations. RESULTS: During weeks when 5% of respiratory specimens tested positive for influenza A, vaccine effectiveness among persons aged ≥65 years was 22% (95% confidence interval [CI], -6%-42%) for all influenza-associated deaths, 25% (95% CI, 13%-37%) for deaths occurring within 30 days after an influenza-associated pneumonia/influenza hospitalization, and 19% (95% CI, 4%-31%) for influenza-associated pneumonia/influenza hospitalizations. Because small proportions of deaths, deaths after pneumonia/influenza hospitalizations, and pneumonia/influenza hospitalizations were associated with influenza virus circulation, we estimated that vaccination prevented 1.6%, 4.8%, and 4.1% of these outcomes, respectively. CONCLUSIONS: By using confounding-reducing techniques with 15 years of provincial-level data including vaccination and health outcomes, we estimated that influenza vaccination prevented approximately 4% of influenza-associated hospitalizations and deaths occurring after hospitalizations among older adults in Ontario. |
When is correlation coevolution?
Nuismer SL , Gomulkiewicz R , Ridenhour BJ . Am Nat 2010 175 (5) 525-37 Studying the correlation between traits of interacting species has long been a popular approach for identifying putative cases of coevolution. More recently, such approaches have been used as a means to evaluate support for the geographic mosaic theory of coevolution. Here we examine the utility of these approaches, using mathematical and computational models to predict the correlation that evolves between traits of interacting species for a broad range of interaction types. Our results reveal that coevolution is neither a necessary nor a sufficient condition for the evolution of spatially correlated traits between two species. Specifically, our results show that coevolutionary selection fails to consistently generate statistically significant correlations and, conversely, that non-coevolutionary processes can readily cause statistically significant correlations to evolve. In addition, our results demonstrate that studies of trait correlations per se cannot be used as evidence either for or against a geographic mosaic process. Taken together, our results suggest that understanding the coevolutionary process in natural populations will require detailed mechanistic studies conducted in multiple populations or the use of more sophisticated statistical approaches that better use information contained in existing data sets. |
Can we "hedge" against the development of antiviral resistance among pandemic influenza viruses?
Shay DK , Ridenhour BJ . PLoS Med 2009 6 (6) e1000103 David K. Shay and Benjamin Ridenhour discuss a modeling study predicting that stockpiling a secondary antiviral for use early in a flu pandemic can forestall resistance to the primary stockpiled drug. |
- Page last reviewed:Feb 1, 2024
- Page last updated:May 13, 2024
- Content source:
- Powered by CDC PHGKB Infrastructure