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Flu Science

How Flu Spreads

About 5% to 20% of the U.S. population gets the flu every year. The CDC estimates that there have been 9 to 41 million flu illnesses a year between 2010 and 2020.

While getting vaccinated is the most effective way of avoiding the flu, understanding how the flu spreads is a big step towards prevention.

Sep 6, 2022
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Flu Prevention

How Can You Prevent the Flu?

Read a few helpful tips to prevent seasonal influenza.

Sep 2, 2022
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Flu Complications

Why Does Flu Affect Some People More Than Others?

Certain people may have higher risk factors for influenza complications.

Sep 5, 2022

Flu Vaccine FAQ


Influenza can cause mild to severe illness. A mild case of the flu may cause you to feel ill and miss work, but more serious complications can happen, too. Of the millions of people who get the flu each year, hundreds of thousands are hospitalized due to flu-related causes, and tens of thousands die from them.

According to the Centers for Disease Control (CDC), annual influenza vaccines are the best protection against the flu. Flu vaccines can reduce the risk of getting sick from the flu and having to be hospitalized for it. You might still get influenza after you’ve been vaccinated, but vaccines can reduce the severity of sickness you might feel if you do catch the flu.


Influenza viruses are continually changing, so flu vaccines need to be updated to protect against the viruses that are considered to be most likely to circulate during each new flu season. Also, the immunity you get from a flu vaccine will lessen over time, so getting a new vaccine for the upcoming flu season will help increase your immunity.

The CDC recommends that adults aged 65 and older receive an adjuvanted or a higher dose flu vaccine. If these two vaccine types are not available, adults of this age group can receive a standard-dose flu vaccine. For other people outside this age group, the CDC does not recommend any particular flu vaccine over another, with rare exception.

If you are trying to decide which vaccine might be best for you, make sure you talk to your doctor or another healthcare professional.