Can You Get the Flu From a Flu Shot?

Many people worry about getting a flu shot because they are afraid they will get the flu from the vaccine. There are so many stories out there about people that came down with the flu a few days after getting the shot. It's easy to understand why people believe this and continue to insist that the vaccine can give you the flu. So, is there any truth to this question?

The short answer is…no, there is no truth to it. It is not possible to get the flu from the flu shot. To put it in technical terms, correlation does not equal causation. Meaning, just because you got the flu (or more likely - another viral illness) soon after getting the vaccine, that doesn't mean the vaccine caused it. 

The injected flu vaccine (the flu shot) is made from a killed virus and the nasal flu vaccine (nasal spray) is made from a weakened live virus. Neither of these vaccines can give a healthy person the flu. It's just not scientifically possible.

What to Expect From a Flu Shot

Possible side effects from the injected flu vaccine include:

  • Soreness, redness or pain at the injection site
  • Low-grade fever
  • Body aches

These side effects usually occur soon after the vaccine is administered and last 1-2 days. On very rare occasions, a severe or life-threatening reaction called Guillain-Barré syndrome may occur. However, even this has not been definitively linked to the vaccine.

What to Expect From the Nasal Flu Vaccine

The CDC's Advisory Committee on Immunization Practices has recommended that the Live Attenuated Influenza Vaccine (LAIV), commonly known as FluMist, not be used during the 2017-2018 flu season due to concerns about low effectiveness during previous flu seasons. Although it is still an approved vaccine, it is unlikely to be available in most places due to this recommendation. 

Possible side effects from the nasal vaccine include:

  • Runny nose
  • Sore throat
  • Headache
  • Cough
  • Nausea and vomiting (in children)
  • Fever (in children)
  • Muscle aches

Because the nasal flu vaccine is a weakened live virus, people in close contact with people who have severely weakened immune systems should not get the nasal flu vaccine.

Very rarely, a person may experience a true significant side effect or reaction from a vaccine. This can occur as a result of any vaccine - not just a flu shot. If you are concerned that you may have had a true injury from a flu shot, you can report it to the National Vaccine Injury Compensation Program. You should also talk to your healthcare provider so she can help you decide whether the vaccine is likely at fault or if your symptoms could be related to something else. 

Was this page helpful?

Article Sources

  • "Questions & Answers: Flu Shot." Centers for Disease Control and Prevention. 24 JUL 2006. US Department of Health and Human Services Centers for Disease Control and Prevention. 
  • "Questions & Answers: The Nasal-Spray Flu Vaccine (Live Attenuated Influenza Vaccine [LAIV])." Centers for Disease Control and Prevention. 13 SEP 2005. US Department of Health and Human Services Centers for Disease Control and Prevention.