Complications of influenza and benefits of vaccination

Uncertainty regarding the benefits of influenza vaccination may contribute to the underutilization of this vaccine. We have conducted serial cohort st udies using the administrative data bases of a Twin Cities based managed ca re organization to assess the impact of disease and benefits of vaccination among the elderly. For the 6 seasons 1990-1991 through 1995-1996, there we re more than 20,000 elderly members of the health plan included in each coh ort. Data collected included information on baseline demographic and health characteristics, vaccination status and outcomes (hospitalizations and dea th). Multivariate regression techniques were used to compare the risks of o utcomes between vaccinated and unvaccinated persons while controlling for c ovariates and confounders. Results for data pooled over the 6 seasons demon strated that influenza vaccination was associated with significant reductio ns in hospitalizations, outpatient visits, and death among the elderly. Sim ilar findings were observed for low, intermediate, and high risk subgroups. Vaccination was also associated with cost savings. These findings are cons istent with results from studies conducted in other countries and over othe r seasons and strongly support age-based recommendations for annual influen za vaccination for all persons ages 65 and over. Published by Elsevier Scie nce Ltd.