The severity of influenza varies widely from year to year. According to the Centers for Disease Control and Prevention (CDC):¹

• Influenza causes more than 220,000 hospital visits each year in the United States.
• The number of cases of flu is highest during the winter months.
• Children have the highest rates of infection.
• Deaths from the flu are highest in people older than 65 and people of any age who have serious medical conditions. More than 90% of flu-related deaths occur in older adults.

Because the flu virus is contagious, it spreads easily among people who live close together, such as in nursing homes and other long-term care facilities. The numbers of people affected and the death rates can be high.

Children younger than 5 and adults ages 65 and older are two of the groups who are most likely to be hospitalized for flu-related illness.

Flu and its complications caused an average of 36,000 deaths in the U.S. between 1990 and 1999.¹