COVID-19 vaccines - what to expect
When to Call the Doctor
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:
- Difficulty breathing, coughing, wheezing, or high-pitched breathing sounds
- Swelling of the face, eyes, tongue, or throat
- Hives, itchiness, redness of the skin
- Lowering of blood pressure
Symptoms of severe reactions may also include:
- Abdominal pain
- Chest discomfort or tightness
- Difficulty swallowing
- Dizziness or lightheadedness
- Nausea or vomiting
- Slurred speech
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 the Pfizer-BioNTech and Moderna vaccine.
This reaction has tended to occur more often in male adolescents and young adults ages 12 to 39 years.
- It occurs more often after the second dose, most often within 7 days after vaccination. Studies show that this rare risk may be reduced by waiting 8 weeks between the first and second dose.
- With proper care and rest, most people who had the reaction got better quickly without any lasting effects.
- For people who had this rare reaction, it is important to talk with a cardiologist (heart doctor) about how and when to return to exercise and sports.
Symptoms of myocarditis and pericarditis include:
- Chest pain
- Shortness of breath
- Fast-beating heart, fluttering, or pounding heart
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:
- Severe allergic reactions NOT related to vaccines or injectable medicines -- such as food, pet, venom, environmental, or latex allergies
- Allergies to oral medicines or a family history of severe allergic reactions
Centers for Disease Control and Prevention website. Allergic reactions after COVID-19 vaccination.
Centers for Disease Control and Prevention website. Getting your COVID-19 vaccine.
Centers for Disease Control and Prevention website. Stay up to date with COVID-19 vaccines.
Last reviewed on: 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 10/02/23.