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Influenza (Flu)

About Flu

Influenza (flu) is a contagious respiratory illness caused by flu viruses that infect the nose, throat, and lungs. Flu can cause mild to severe illness, and at times can lead to death.

People at Higher Risk of Flu Complications

grandparents with baby

Certain people are at "high risk" of serious complications from seasonal influenza including:

  • People 65 years and older
  • Children younger than 5 years old
  • Pregnant women
  • People of any age with certain chronic medical conditions

Note: There is no recommendation that pregnant people or people with pre-existing medical conditions need to get special permission or written consent from their doctor or health care professional for influenza (flu) vaccination if they get vaccinated at a worksite clinic, pharmacy or other location outside of their physician’s office. Pregnant people should not get nasal spray flu vaccine. More information is available at Misconceptions about Seasonal Flu and Flu Vaccines.

Flu Vaccine

ful mild to wild

Find a flu vaccination site near you

Everyone 6 months or older should get a flu vaccine every year.

The best way to prevent flu and lower the risk of its complications is by getting vaccinated each year. Flu viruses change each year so you need a new vaccine every year.

The flu vaccine is not approved for children younger than 6 months old. But, infants in this age group have a higher risk of flu complications than children of any other age.  The best way to protect children younger than 6 months is to make sure members of their household and their caregivers are vaccinated.

The best time to get vaccinated is as soon as the vaccine is available. You can still get a flu shot through the fall, winter or spring, since flu season usually peaks in February but continues through May. 

Flu Signs and Symptoms

People who have the flu often feel some or all of these signs and symptoms that usually start suddenly, not gradually:

Flu and Other Respiratory Viruses


Respiratory Syncytial Virus (RSV)


How Can I Prevent the Flu?

Take these actions: 

  1. Get a flu vaccine.
  2. Wash your hands.
  3. Stay home if you're sick.
  4. Take flu antiviral drugs if your doctor prescribes them.


If you get sick with flu, call your healthcare provider and ask about antiviral drugs.  These drugs work best when started early, such as 1 to 2 days after your flu symptoms begin.  When treatment is started within 1-2 days after flu symptoms begin, it can lessen symptoms and shorten the time you are sick.

For questions about flu, call your healthcare provider. See Health Insurance & Low Cost Healthcare Services if you do not have a healthcare provider.  

For people at higher risk of serious flu complications, treatment can mean the difference between milder or more serious illness possibly resulting in a hospital stay.

People at higher risk of flu complications include young children, adults 65 years of age and older, pregnant people, and people with certain medical conditions such as asthma, diabetes and heart disease.

Flu Activity & Surveillance

Additional Information & Resources