Can You Get the Flu From a Flu Vaccine?

Every fall, doctors and hospitals gear up to begin giving flu vaccines to people who want or need to avoid getting sick with the flu. Some people steadfastly refuse to get a shot, maintaining that they will "get sick with the flu" if they get the shot.

Flu Shot and Nasal Vaccine Components

• The flu shot contains inactivated (killed) virus that is grown in chicken eggs. The nasal spray flu vaccine is made from a weakened (live) flu virus that will not cause the flu once you receive the vaccine. This form of the vaccine is sometimes called the "live attenuated influenza vaccine" (LAIV).

Can You Get the Flu From the Shot?

• You cannot "get the flu" from either the flu shot, given in the arm, or the nasal spray vaccine. Because the virus in the vaccines is either killed or weakened, your body will develop antibodies for the current year's flu strain, but the virus in the vaccines is unable to make you sick. This mistaken impression prevents people who should get the vaccine from receiving it because they believe they will become as ill as someone who has caught the flu. If you receive your flu shot between September and December (or January), you are protected from the current flu strain making the rounds, if researchers correctly predicted which strain would be causing illness.

Post-Vaccine Symptoms

• You will develop soreness at the vaccination site, body aches and a low-grade fever. This is not the flu, only the post-vaccine side effects. In rare cases, some people develop more serious side effects, such as a severe allergic reaction to the chicken eggs in which the vaccine is grown. These mild symptoms are what some people may mistake as "getting sick with the flu after getting the flu shot."

Who Should Get a Flu Shot

• People with a chronic illness such as diabetes or asthma; those 50 years old or older; children between six months and 19 years of age; pregnant women; people living in nursing homes or other long-term care facilities; those who care for high-risk populations; family members and caregivers (out of the home) of children younger than six months; and family members of those at high risk for flu complications should receive an annual flu shot.

Who Should Not Get a Flu Shot

• Anyone who has ever developed a severe allergic reaction to eggs or a previous flu shot or anyone with a history of Guilllain-Barre Syndrome should not get the flu shot. Delay for flu shot if you are sick and you have a fever; it is better to wait until you have gotten over your illness. If you are sick with a mild illness and have no fever, you can go ahead and receive your flu shot.