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Potential Side Effects of the COVID-19 Vaccine

People can have different reactions to vaccines. Most reactions are mild and get better within a few hours or a day or two after your vaccination. The following provides an overview of potential reactions.

Common side effects: Symptoms like fever, chills, muscle aches, fatigue, headache

This is normal. It can start within 24 hours of getting the vaccine. It can last for 2 or 3 days.

You can take acetaminophen or ibuprofen, as needed to help with these symptoms.

If you have any of the symptoms below, please contact your provider for further advice, as you may need a COVID-19 test:

  • A high fever
  • Symptoms lasting more than a few days
  • Symptoms that could be from COVID-19 (like a new sore throat, cough, nasal congestion, runny nose, loss of smell or taste, or shortness of breath) 
  • A new exposure to someone who has COVID-19

If you have an upcoming visit, procedure, or surgery and are having symptoms, please let your care team know.

You can get another dose at the appropriate time with the standard 15 minutes of monitoring.

Not unless directed by your doctor. It is not recommended to take these before your additional required doses to prevent these symptoms from occurring again. Medications for fever or pain can be taken for these symptoms if needed. We do not know what happens to your immune response to the COVID-19 vaccine if you take these medications after getting it.

Common side effects: Redness, swelling, and/or itching where you got the vaccine

This is normal. It can be very large. This usually lasts for 2 or 3 days but can last as long as 7 days. It can also start 7–10 days after your vaccine. You may get swelling in the armpit of the arm you got the vaccine. This should get better on its own within 7 days.

If there is itching, you can take an antihistamine (like diphenhydramine). If there is pain, you can take acetaminophen. Ice can be helpful for swelling.

If the redness and swelling stay at the site you got vaccinated and you have no other symptoms of allergic reaction (see below), then you do not need to see or talk to anyone.

If you also have any allergy symptoms, see below for guidance.

If the swelling in your armpit lasts longer than 7 days, you should contact your provider.

As long as you have no allergic symptoms, you can receive another dose of vaccine at the appropriate time. You should get any additional required doses with the standard 15 minutes of monitoring.

Mild allergic reactions

Hives, itching, rash (except where you got the vaccine)

You can take an over-the-counter antihistamine.

If this occurs within 4 hours of your vaccine, please contact your provider.

You should be evaluated by a doctor to determine whether you can receive another dose at the appropriate time. You may need skin testing.

If this occurs more than 4 hours after your vaccine and you develop other allergic symptoms (see below), seek emergency care. If you do not develop further symptoms but are concerned, please contact your provider.

If you don’t develop any other allergic symptoms, you can get another dose of vaccine at the appropriate time but should be monitored for 30 minutes.

Severe allergic reactions (anaphylaxis)

  • Swelling of lips, face, eyes, tongue
  • Nausea/throwing up or belly pain
  • Tightness in throat or difficulty swallowing
  • Persistent difficulty breathing or shortness of breath
  • Cough or wheezing
  • Dizziness or lightheadedness

For most people, this usually occurs immediately after the vaccination – within 15 minutes. You will be monitored at the vaccine clinic during that time.

If you have these symptoms after you go home, please call your provider or seek emergency care.

You should be evaluated by a doctor to determine whether you can receive another dose at the appropriate time. You may need skin testing.

Updated November 2, 2021