Global Flu Cases Each Year
Each year, the influenza virus causes an estimated 1 billion cases worldwide, according to the World Health Organization. Seasonal flu activity peaks during colder months in both hemispheres. Most cases are mild, but the virus can lead to severe illness in vulnerable groups.
U.S. Flu Cases and Hospitalizations
In the United States, the Centers for Disease Control and Prevention estimates that flu results in 9 million to 41 million illnesses annually. Hospitalizations typically range from 140,000 to 710,000 per year. Deaths can vary widely depending on the severity of the circulating strains.
Who Is Most at Risk
Young children, adults over 65, pregnant individuals, and people with chronic conditions face higher risks of severe flu outcomes. These groups are more likely to require medical care or hospitalization during flu season. Annual vaccination remains the most effective way to reduce risk.
For detailed flu surveillance data, visit CDC Flu Surveillance.
