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Influenza (Flu) Vaccine Safety

Flu Disease and How to Protect Against It

Flu is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness. Serious outcomes of flu infection can result in hospitalization or death. Some people, such as older people, young children, and people with certain health conditions, are at high risk for serious flu complications. You can protect against flu with safe, effective vaccination.

Flu Vaccine Side Effects

Flu vaccines are very safe. Vaccines, like any medicine, can have side effects. Most people who get the flu vaccine have no side effects at all. Some people report having very mild side effects, like a sore arm from the shot for a day or two. The most common side effects are usually mild and go away on their own.

Common Side Effects of Flu Vaccine:

  • Sore, red, or swollen arm from the shot
  • Hoarseness
  • Sore, red or itchy eyes
  • Cough
  • Fever
  • Aches
  • Headache
  • Itching
  • Fatigue

Young children who get inactivated flu vaccine and pneumococcal vaccine at the same time may be at increased risk for seizures caused by fever. Tell your doctor if a child who is getting flu vaccine has ever had a seizure.

Brief fainting spells can happen after any medical procedure, including vaccination. Sitting or lying down for about 15 minutes can help prevent fainting, and injuries caused by a fall. Tell your doctor if you feel dizzy, or have vision changes or ringing in the ears.

Severe shoulder pain and reduced range of motion in the arm where a shot was given can happen, very rarely, after a vaccination.

Severe allergic reactions from a vaccine are very rare, estimated at less than 1 in a million doses. If one were to occur, it would usually be within a few minutes to a few hours after the vaccination.

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Available Flu Vaccines

For information on available flu vaccines, please visit Approved Influenza Vaccines.

How CDC Monitors Flu Vaccine Safety

CDC and FDA continuously monitor the safety of vaccines after they are approved.  If a problem is found with a vaccine, CDC and FDA will inform health officials, health care providers, and the public.

CDC uses three systems to monitor vaccine safety:

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More Resources

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