An estimated 19 million influenza illnesses occur in the United States each year. From 2005-2011, influenza vaccination was estimated to prevent 13.6 million illnesses, 5.8 million medical visits, and nearly 113,000 influenza-related hospitalizations (Kostova et al., 2013).
Annually over 200,000 people in the United States are hospitalized because of the flu. People at highest risk for flu-related complications include children younger than 5 years (especially those younger than 2 years old), adults 65 years of age and older, pregnant women, and people who have certain medical conditions such as asthma, heart disease, chronic lung disease, kidney disease, or weakened immune systems due to disease or medication.
Each year, thousands of people in the U.S. die because of the flu (Thompson MG et al., 2010). Most of the flu-associated deaths occur in adults 65 years of age and older. More people die from complications from the flu than from any other vaccine-preventable disease.