What is the flu?

The flu is an illness caused by flu viruses. The flu may make people cough and have a sore throat and fever. They may also have a runny or stuffy nose, feel tired, have body aches, or show other signs they are not well. The flu happens every year and is more common in the fall and winter in the U.S. People of all ages can get the flu, from babies and young adults, to the elderly.

This fall, when you see signs reading “Get Your Flu Vaccine,” you might ask “Isn’t it too late to get vaccinated?” No, it’s not too late! CDC recommends that flu vaccination efforts continue throughout the flu season. While the sooner you get vaccinated the more likely you are to be protected against the flu when activity picks up in your community, vaccination into December and beyond can be beneficial during most flu seasons. View CDC’s influenza summary map for a weekly update on flu activity in the United States.

“Flu season most often peaks between December and March, but activity can occur as late as May,” says Dr. Dan Jernigan, Director of the Influenza Division at CDC. “We are encouraging people who have not yet been vaccinated this season to get vaccinated now.” It takes about two weeks after vaccination for antibodies that protect against influenza virus infection to develop in the body, so it’s best to get vaccinated early.

For millions of people every season, the flu means a fever, cough, sore throat, runny or stuffy nose, muscle aches, fatigue, and miserable days spent in bed. Millions of people get sick, hundreds of thousands are hospitalized, and thousands to tens of thousands of people die from flu each year.

There is a vaccine that can help prevent flu. While the vaccine varies in how well it works, there are many studies that show that flu vaccination can reduce flu illnesses, doctor visits, and missed work and school due to flu, as well as prevent flu-related hospitalizations.

CDC recommends a yearly flu vaccine for everyone 6 months of age and older as the first and most important step in protecting against seasonal flu viruses. This season, CDC recommends the use of injectable flu vaccines (flu shots) and not the nasal spray flu vaccine. The nasal spray flu vaccine (live attenuated influenza vaccine or LAIV) is not recommended for use this season because of concerns about effectiveness.

To learn more about the flu and vaccination information, visit the Centers and Disease Control website. As always, remember to discuss any health information with your doctor.