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Disease Burden of Influenza

The severity of influenza disease in the United States can vary widely and is determined by a number of things including the characteristics of circulating viruses, the timing of the season, how well the vaccine is working to protect against illness, and how many people got vaccinated. CDC tracks severity principally through its national Influenza Surveillance System that monitors key indicators like the percentage of deaths resulting from pneumonia or influenza, rates of influenza-associated hospitalizations, pediatric deaths and the percentage of visits to outpatient clinics for influenza-like illness. In addition to using surveillance data, CDC uses mathematical models to fill in the picture of the disease burden and the impact of influenza immunization programs. Models are used to augment surveillance because most of the surveillance systems only look at portions of the U.S. population and in some cases there can be significant under-reporting of influenza deaths and hospitalizations. This page includes links to key resources on the burden of influenza.

Flu-related Illness and Hospitalization

Flu-related illness and hospitalization averted by vaccination
2014-2015 season
2013-2014 season
2012-2013 season
2011-2012 season
2005-2011 seasons

Flu-related Deaths

Flu-related deaths averted by vaccination

Economic Impact of Influenza

Infographics

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