Estimated Influenza Illnesses and Hospitalizations Averted by Influenza Vaccination — United States, 2012–13 Influenza Season

Influenza is associated with substantial morbidity and mortality each year in the United States. From 1976 to 2007, annual deaths from influenza ranged from approximately 3,300 to 49,000. Vaccination against influenza has been recommended to prevent illness and related complications, and since 2010, the Advisory Committee on Immunization Practices has recommended that all persons aged ≥6 months be vaccinated against influenza each year. In 2013, CDC published a model to quantify the annual number of influenza-associated illnesses and hospitalizations averted by influenza vaccination during the 2006-11 influenza seasons. Using that model with 2012-13 influenza season vaccination coverage rates, influenza vaccine effectiveness, and influenza hospitalization rates, CDC estimated that vaccination resulted in 79,000 (17%) fewer hospitalizations during the 2012-13 influenza season than otherwise might have occurred. Based on estimates of the percentage of influenza illnesses that involve hospitalization or medical attention, vaccination also prevented approximately 6.6 million influenza illnesses and 3.2 million medically attended illnesses. Influenza vaccination during the 2012-13 season produced a substantial reduction in influenza-associated illness. However, fewer than half of persons aged ≥6 months were vaccinated. Higher vaccination rates would have resulted in prevention of a substantial number of additional cases and hospitalizations.