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Vaccine side effects versus COVID-19 symptoms

Some side effects are common after vaccination. They are a result of your body responding to the vaccine (it's also okay if you don't have any side effects at all). Common side effects from the vaccine can include pain, swelling, or redness where the shot was given, and sometimes feeling achy and tired. Some people may have a headache or fever.

Some side effects can be the same or similar as symptoms of COVID-19 or other illnesses. The COVID-19 vaccine cannot give you COVID-19 disease. For example, these conditions after vaccination could be from the vaccine or other illness:

  • Fever

  • Extreme tiredness

  • Headache

  • Chills

Other symptoms are less likely to be side effects of the vaccine but are signs of possible illness. If you have any of the below symptoms, you should get tested for COVID-19 and other illnesses as recommended by your health care provider if you have any of these symptoms:

  • Loss of taste or smell

  • Cough

  • Shortness of breath

  • Nasal congestion, or stuffy or runny nose

  • Sore throat

Serious adverse events

A serious adverse event is something that is life-threatening. Most adverse effects occur in the six weeks after getting a vaccine.

If you have a severe reaction, contact your health care provider. Providers should report severe reactions to the Vaccine Adverse Event Reporting System (VAERS). This reporting system helps the CDC and FDA continue to monitor the safety of COVID-19 vaccines.


CDC has also launched a new patient reporting tool for COVID-19 vaccine. It is a smartphone app called v-safe. This app can help with active monitoring for COVID-19 vaccine safety after you get the COVID-19 vaccine. Your health care provider will give you more information on v-safe. You can learn more at V-safe After Vaccination Health Checker.

  • Poster: Get vaccinated. Get your smartphone. Get started with v-safe (PDF)

  • Fact sheet: Get vaccinated. Get your smartphone. Get started with v-safe (PDF)

Going to work or school when you have side effects

Side effects can happen after vaccination and can be similar to symptoms of illnesses, like COVID-19. These side effects can include pain, swelling, or redness where the shot was given. Less common side effects can include headache, fatigue, or fever.

  • If you are experiencing side effects where the shot was given (such as pain, swelling, or redness), but you are otherwise well, you can return to work or school. Typically, side effects start within a day of receiving the vaccine and may last for three days.

  • If you are experiencing other symptoms of illness like fever, headache, or noticeable tiredness, then you should stay home. These may or may not be due to the vaccine. With any of these symptoms, stay home until your symptoms are improved and you have not had a fever for 24 hours. If symptoms worsen or last longer than three days, stay home and call your health care provider. Because the virus that causes COVID-19 is still in our communities, it is possible that you were exposed to COVID-19 before or around the same time you were vaccinated, so it may be helpful to get tested.

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