COVID-19 vaccines - what to expect

Contact your provider if you have any questions or concerns about COVID-19 vaccines.

In rare cases, people have had severe and non-severe allergic reactions to the COVID-19 vaccines. If you have a severe allergic reaction (anaphylaxis) after getting the first shot of the COVID-19 vaccine, you should not get the second shot. Talk with your provider to see if there are other options.

If you think you are having a severe reaction to a COVID-19 vaccine after leaving the vaccination site, you should call 911 or the local emergency number right away. Symptoms of severe allergic reaction appearing in the first 4 hours after receiving the vaccine include:

Symptoms of severe reactions may also include:

If you notice any unusual or concerning symptoms, seek medical care right away.

Rare cases of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the outer lining of the heart) have been reported in children and teens ages 5 years and older after getting a COVID-19 vaccine.

This reaction has tended to occur more often in male adolescents and young adults ages 12 to 39 years. However, it also has occurred in females, in other age groups, after other doses, and after receiving the Novavax vaccine.

Symptoms of myocarditis and pericarditis include:

If your child or teenager has any of these symptoms, get medical help right away.

All these associations are so rare that they should not cause hesitation in receiving any of these vaccines.

CDC recommends that people may still get vaccinated if they have a history of:

Centers for Disease Control and Prevention website. Allergic reactions after COVID-19 vaccination. www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/allergic-reaction.html. Updated December 14, 2023. Accessed August 26, 2024.

Centers for Disease Control and Prevention website. Staying up to date with COVID-19 vaccines. www.cdc.gov/covid/vaccines/stay-up-to-date.html. Updated July 3, 2024. Accessed August 26, 2024.



Review Date: 2/22/2023
Reviewed By: Frank D. Brodkey, MD, FCCM, Associate Professor, Section of Pulmonary and Critical Care Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. Editorial update 08/26/2024.
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