Flu Diagnosis and Treatment »

Flu Shots

Flu shots are the most effective way to protect against the flu. The flu shot is an inactivated vaccine (containing killed virus) that is given with a needle, usually in the arm. The flu shot is approved for use in people older than 6 months, including healthy people and people with chronic medical conditions. The most important groups of persons who should get flu shots are those who are at highest risk for developing serious complications from the flu.

The flu shots contains three influenza viruses-one A (H3N2) virus, one A (H1N1) virus, and one B virus. The viruses in the vaccine change each year based on international surveillance and scientists' estimations about which types and strains of viruses will circulate in a given year. About 2 weeks after vaccination, antibodies that provide protection against influenza virus infection develop in the body.

The flu shots are 70-90% effective in persons younger than age 65, and about 50% effective in older individuals. It will protect 85% of the elderly from dying from the flu or its complications. Even if a vaccinated individual does manage to catch the flu, the symptoms will usually be milder than had they not received the shot.