No, the flu shot does not give you the flu

Flu season has begun and the CDC is recommending that everyone over the age of 6 months get an influenza vaccine. Flu shots reduce the risk of getting the flu or make symptoms less severe for those who do get it. 

Brenda reached out to VERIFY to ask if the flu shot actually gives you the flu. 

THE QUESTION

Will the flu shot give you the flu?

THE SOURCES

• Joe Gastaldo, M.D., infectious disease specialist in Columbus, Ohio

• Kristin Englund M.D. in a Cleveland Clinic article

• MedlinePlus, a service of the National Library of Medicine

• U.S. Centers for Disease Control and Prevention

• World Health Organization

• Mayo Clinic

THE ANSWER 

No, the flu shot will not give you the flu.

WHAT WE FOUND

Some people think they will be injected with an infectious virus that will make them sick when they get a flu shot, but that’s false. The Centers for Disease Control and Prevention, World Health Organization and Mayo Clinic all say the vaccine is made up of an inactive virus that cannot give you the flu. This inactivated virus is either “no longer infectious, or a particle designed to look like a flu virus to your immune system,” the CDC says. 

"The flu shot is not a live virus. Scientifically and physiologically, it is impossible for someone to pass it on to someone else,” Joe Gastaldo, M.D., told VERIFY’S partner station 10TV. 

A live virus vaccine would use a weakened form of the virus, while an inactive vaccine is “made from a protein or other small pieces taken from a virus or bacteria,” according to MedlinePlus. 

The misconception of the flu shot giving a person the flu is likely because the vaccine can cause side effects that include flu-like symptoms. The CDC says the most common flu shot side effects include “soreness, redness, tenderness or swelling where the shot was given.” They also note that low-grade fever, headache and muscle aches are potential side effects.

In a Cleveland Clinic article, Kristin Englund M.D., describes flu shots as “a way of tricking your body into thinking it has the flu. That causes it to make the antibodies that will eventually protect you if you’re exposed to the virus.” 

These side effects should only last a day or two, according to the World Health Organization. 

While most flu vaccines are given with a needle, there is a nasal spray flu vaccine that contains a live weakened virus. This version of the vaccine “should not be given to someone with a weakened immune system or someone that's pregnant or to someone who is around someone with a weakened immune system," Gastaldo says.