I have heard numerous reports in the media where they make mention of the "live flu virus" in the flu vaccine, specifically "flu-mist." This is mentioned in conjunction with a warning to avoid contact with this and that (yadda, yadda) for a certain time period. This confuses me. I was under the impression that the flu vaccines contain dead viruses and that it was not possible to catch the flu from the vaccine. Which is it?

Each year, influenza (a.k.a. "the flu") affects one in every ten Americans. Common flu symptoms include:

• fever
• cough
• fatigue
• runny nose
• headache
• muscle aches
• sore throat

Those of us hoping to avoid such unpleasantness might consider vaccination. Flu vaccines protect against those strains of the virus experts have identified as most likely to make the rounds during a flu season. Flu vaccines are administered either by injection or by nasal inhalation. The injected vaccine contains dead flu viruses. On the other hand, FluMist, the inhaled version, contains attenuated, or weakened, flu viruses.

Though the viruses in FluMist are weakened, people receiving this version of the vaccine need to avoid close contact, for about three weeks, with individuals who have compromised immune systems. This is because those with compromised immune systems are more likely to develop symptoms from exposure to the weakened viruses present in the vaccine. The injected vaccine, which is made up of dead viruses, doesn't pose this risk.

For detailed information about who needs to consider FluMist, visit the U.S. Food and Drug Administration (FDA) "Questions and Answers on FluMist" web page. For related information about flu shots (the injected vaccine), read the Related Q&As listed below.

Alice

Related Q&As

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