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Children's Vaccines Health Center

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Seasonal Flu Shot and Nasal Spray


Can Getting the Seasonal Flu Vaccine Cause the Flu? continued...

The flu shot can be given to children and teens ages 6 months to 19 years, pregnant women, adults ages 50 and older, people with certain chronic medical conditions, people who live in facilities such as nursing homes, and people who live with or take care of others who are at high risk for flu complications. Also available are intradermal shots. These injections, approved for those ages 18 to 64, use smaller needles and only go into the top layer of the skin instead of deeper into the muscle.

For those age 65 and older, a high-dose version of the flu vaccine called Fluzone is recommended when available. It may be more effective at protecting the elderly because their immune systems are more fragile.

Why Do People Need a Flu Vaccination Every Year?

The seasonal flu vaccine is changed every year. Each year, a panel of experts from agencies such as the FDA and the CDC studies the available data and decide which three or four strains of influenza viruses will most likely be active during the next flu season. In February, they advise the manufacturers which strains of viruses to use in making the vaccine. So, each year the vaccine being used is different than the vaccine used the year before.

How Effective Is the Seasonal Flu Vaccine?

The seasonal flu vaccine is about 80% effective in preventing flu. It takes about two weeks for the body to become protected after getting the seasonal flu vaccine.

The viruses used in the vaccine may not be the only strains causing the flu; it's possible you could be infected with a virus you do not have immunity against. People who get the flu after getting a flu shot typically have a milder and shorter case of flu.

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