Influenza vaccination is not associated with a reduction in the risk of recurrent coronary events

Abstract

Acute respiratory infections, including influenza, have been suggested as possible precipitants of acute cardiac events. To evaluate whether influenza vaccination prevents recurrent coronary events, the authors conducted a population-based inception cohort study of 1,378 Group Health Cooperative enrollees who survived a first myocardial infarction in 1992 through 1996. Recurrent coronary events, influenza vaccinations, and other covariates were identified by chart review and from administrative data systems. A Cox proportional hazards model was used to evaluate the association of receipt of each year's influenza vaccine with subsequent risk of recurrent myocardial infarction and death from atherosclerotic cardiovascular disease. A total of 127 recurrent coronary events were identified during the median 2.3-year follow-up period. Influenza vaccination was not associated with risk of recurrent coronary events during the corresponding period of November through October (adjusted hazard ratio (HR) = 1.18, 95% confidence interval (CI): 0.79, 1.75) or during the corresponding periods of expected influenza activity (November through April) (HR = 1.06, 95% CI: 0.63, 1.78) or inactivity (May through October) (HR = 1.34, 95% CI: 0.76, 2.36). These results suggest that the benefit of influenza vaccine for older adults does not extend to protection against recurrent coronary events.