Flu Vaccine FAQs

Will I get the flu from a flu shot?

The viruses in the flu shot are killed (inactivated), so you cannot get the flu from a flu shot. The risk of a flu shot causing serious harm is extremely small. However, a vaccine, like any medicine, may rarely cause serious problems, such as severe allergic reactions. Almost all people who get influenza vaccine have no serious problems from it.

Some people who should talk with their doctor before getting the flu vaccination include:

  • People who are have a severe allergy to hens’ eggs

  • People who have had a severe reaction to a flu vaccine in the past

  • People who previously developed Guillain-Barré Syndrome (GBS) in the 6 weeks after getting a flu shot

Sometimes, a person will experience flu-like symptoms after receiving the vaccination. There are several reasons why this might happen:

  • People may be exposed to an influenza virus shortly before getting vaccinated or during the two-week period that it takes the body to gain protection after getting vaccinated. This exposure may result in a person becoming ill with flu before the vaccine begins to protect them.

  • People may become ill from another non-flu virus circulating during the flu season, that can also cause flu-like symptoms (such as rhinovirus).

  • A person may be exposed to an influenza virus that is not included in the vaccine.

Unfortunately, some people can remain unprotected from flu despite getting the vaccine. This is more likely to occur among people who have weakened immune systems. However, even then, the flu vaccine can still help prevent influenza complications.

What is FluMist® and how does it differ from the flu shot?

The nasal-spray flu vaccine FluMist (sometimes called LAIV for Live Attenuated Influenza Vaccine) is different from the other licensed influenza vaccine (also called the “flu shot”) because it contains weakened live influenza viruses instead of killed viruses and is administered by nasal spray instead of injection.

When the viruses are sprayed into the nose, they stimulate the body’s immune system to develop protective antibodies. The weakened viruses are cold-adapted, which means they are designed to only cause infection at the cooler temperatures found within the nose. The viruses cannot infect the lungs or other areas where warmer temperatures exist.

After reviewing data from previous flu seasons, the CDC decided not to recommend the use of FluMist for the 2016-17 flu season.