Clinical Effectiveness of Influenza Vaccination in Persons Younger Than 65 Years With High-Risk Medical Conditions

Abstract

Influenza continues to be a major cause of annual morbidity and mortality.^1,2 Serious complications include pneumonia,^2,3 acute otitis media⁴ and exacerbations of acute pulmonary,⁵ cardiac, or cerebrovascular disease.^2,6,7 In the United States each year, 140 000 hospital admissions and over 36 000 deaths are attributed to influenza.⁸ Corresponding figures of excess deaths reported for European countries such as the United Kingdom, Denmark, and the Netherlands are 11 000,⁹ 400,¹⁰ and 2000, respectively.¹¹