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Side Effects of the Inactivated Influenza Vaccine

Because the vaccine contains killed virus, the influenza shotform.gif(What is a PDF document?) cannot cause the flu. If you develop the flu after being immunized, it may be because you were exposed to the flu virus before receiving the injection or you were exposed to another virus that the vaccine did not protect against.

Some minor side effects of the immunization have been reported and may include:

Recommended Related to Adult Vaccines

Meningococcal Vaccine for Adults

The meningococcal vaccine protects against four types of meningococcal bacteria -- germs that cause meningococcal disease. Meningococcal disease can affect the lining around the brain or spinal cord (meningitis). Or, it can cause a blood infection (meningococcal bacteremia), pneumonia, or other problems. One in 10 infected people die from meningococcal disease. Those who survive may have lasting disabilities such as hearing loss or brain damage. That's why the meningococcal vaccine is so important...

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  • Discomfort at the site of the shot. This is the most frequent side effect in adults and may last 1 to 2 days.
  • Fever, vague feelings of weakness, and muscle aches. These may occur 6 to 12 hours after the flu shot and last 1 to 2 days.

Acetaminophen or ibuprofen can help relieve any minor side effects. Do not give aspirin to anyone younger than 20 because of the risk for developing Reye syndrome.

No reports have been confirmed of Guillain-Barré syndrome developing in people as a result of the influenza vaccine since the 1976 vaccination program. During that year, the swine flu vaccine was associated with an increase in the syndrome. Guillain-Barré syndrome is the only known possible fatal reaction to influenza vaccine and is extremely rare. The risk of death from the flu vaccine is estimated at 1 person out of 2 million and is significantly lower than the risk of dying from complications caused by the flu.

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Christine Hahn, MD - Epidemiology
Last Revised July 8, 2010

WebMD Medical Reference from Healthwise

Last Updated: July 08, 2010
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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