Mortality Associated With Influenza and Respiratory Syncytial Virus in the United States

Abstract

Influenza infections result in substantial morbidity and mortality nearly every year^1,2 and estimates of this burden have played a pivotal role in formulating influenza vaccination policy in the United States.³ However, numbers of deaths attributable to influenza are difficult to estimate directly because influenza infections typically are not confirmed virologically or specified on hospital discharge forms or death certificates. In addition, many influenza-associated deaths occur from secondary complications when influenza viruses are no longer detectable.^4,5 Nonetheless, wintertime influenza epidemics have been shown to be associated with increased hospitalizations and mortality for many diagnoses, including congestive heart failure, chronic obstructive pulmonary disease, pneumonia, and bacterial superinfections.^6-9