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Flu Shot Failure? Questions & Answers

The annual flu vaccine may not be as effective this year as in past years, the CDC has announced. Here's why.


Q. Who determines which influenza strains go into each year's vaccine?

The CDC collaborates with the World Health Organization (WHO) and other groups to track the flu virus throughout the world. These organizations also monitor influenza activity and virus isolates throughout the world to monitor disease activity and forecast the appropriate components for each year's flu vaccine.

Because of this year's vaccine mismatch, a government scientific advisory board recommended for the first time this week a complete overhaul of the makeup of the flu vaccine for next year. This move would replace all three flu virus strains in this year's vaccine with three new strains for next year flu season.

Q.  Who should get a flu shot?

An annual flu shot is recommended for anyone who wants to reduce his or her chances of getting the flu. The flu shot is highly recommended for certain high-risk individuals who are more prone to flu complications, such as pneumonia. The CDC defines higher-risk people as the following:

  • People 50 years or older
  • People who live in nursing homes or long-term care facilities
  • People with certain chronic medical conditions
  • Women who are pregnant
  • All children age 6 months to 18 years.

The CDC also recommends that persons in close contact with someone in a high-risk group, people who care for children less than 6 months old, and health care workers be vaccinated.

Q. Do children need to get two doses of the flu vaccine the first time they are vaccinated?

Yes. A CDC study presented to the Advisory Committee on Immunization Practices panel showed that the flu vaccine in the past two flu seasons (2005-2006 and 2006-2007) was 75% effective -- but only if children got two doses the first time they were vaccinated.

Q.  Can the flu shot cause the flu?

No, the flu shot cannot cause the flu because it does not contain a live virus. This flu shot is an inactivated (killed) virus that is given with a needle. The nasal influenza vaccine called FluMist contains weakened viruses, which do not cause flu illness but sometimes can cause reactions such as runny nose, nasal congestion, and sore throat.

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