Influenza in People
A young girl, stricken with influenza during the 1957 pandemic, gargles with salt water in a hospital ward in Japan.
MIS 58-15573-68, National Museum of Health and Medicine
Sudden Symptoms
Influenza symptoms usually appear suddenly, and can include fever, body aches, cough, sore throat, and headaches.
Anyone can get flu, but some people are at high risk of developing serious flu complications, such as pneumonia. People at high risk include those 65 years and older, people with certain chronic medical conditions, pregnant women, and children younger than 5 years. Influenza illness can range in severity from mild to severe.
Enrollees at the Civilian Conservation Corps at Pilgrim Creek Camp are inoculated against influenza, circa 1933
Reeve 63084, National Museum of Health and Medicine
The Importance of Influenza Vaccines
Influenza virus infection is so common, we can only estimate the number of people infected each season. CDC estimates that between 9 million and 45 million people get sick with the flu each year in the U.S.
Each season, the overall severity of influenza illness measured through cases, hospitalizations and deaths can vary. The influenza viruses that spread and cause illness during a flu season may have unique characteristics that impact disease severity, so as different influenza viruses circulate from one season to the next, disease severity varies.
CDC recommends receiving a flu vaccine each year as the first and most important step in protecting against flu viruses.