Five Things You Need to Know About COVID-19 Vaccines and Alleric Reactions

July 12, 2021   Dr. Lakiea Wright MD MAT MPH  

Dr. Lakiea Wright is the Medical Director of U.S. Clinical Affairs in the Immunodiagnostics Division at Thermo Fisher Scientific and a board-certified physician in internal medicine and allergy and immunology. She is a staff physician at Brigham and Women’s Hospital.

This is both an incredibly hopeful time and a scary one. As of late April 2021, all Americans ages 16 and older are eligible to get a COVID-19 vaccination.This is incredible news. However, there are a lot of questions and fears surrounding the vaccines, particularly for those with allergies. If you’re one of those people, you might be asking:

  • How common are allergic reactions to the COVID-19 vaccines?
  • How do I know if I’m allergic to the COVID-19 vaccine?
  • Is the vaccine safe for me to receive?

As an allergist, many of my patients have come to me for these answers in recent months. That’s why I decided to write this article and address what I believe are the five most important things you should know about COVID-19 vaccines when it comes to allergic reactions.

1. I have allergies. Is it safe for me to get a COVID-19 vaccine?

The short answer is probably yes. You should tell whoever is administering the vaccine about your allergies and concerns at the time of your appointment. He or she will answer your questions and will not give you the shot if it’s not safe to do so.

Here’s the longer answer, all based on guidance from the Centers for Disease Control (CDC):2

  • It depends on if you’re allergic to any of the ingredients in the approved vaccines.
    If you have respiratory allergies, like the kind that flare up in spring or when you’re around someone’s cat, you can still get a COVID-19 vaccine.
  • If you have a food allergy, note that there are no food products in any of the FDA-authorized vaccines, so you can still get a COVID-19 vaccine.
  • If you are allergic to stinging insect venom, like that of bees or wasps, you can still get a COVID-19 vaccine.
  • If you have had an immediate allergic reaction, severe or otherwise, to a different vaccine, talk to your healthcare provider before getting a COVID-19 vaccine. He or she will help you decide if it’s safe to proceed.
  • If you have a history of severe allergic reactions* (e.g.., anaphylaxis), discuss the situation with your healthcare provider. However, a history of anaphylaxis does not rule out getting a COVID-19 vaccine.
  • If you’ve ever had a severe allergic reaction to any of the ingredients found in the vaccines, the CDC recommends that you don’t receive a vaccine at this time.

When deciding whether to get the vaccine, discuss any concerns with your healthcare providers—severe allergic reactions to the vaccine ingredients are very rare.3,4

Find ingredient lists for the currently authorized vaccines below:

*An allergic reaction is considered severe when a person needs to be treated with epinephrine or if he or she must go to the hospital.2

2. How common are severe allergic reactions to the COVID-19 vaccines?

Based on preliminary reports from the CDC, severe allergic reactions are reported to be five per million with the Pfizer vaccine and 2.5 per million with Moderna. The rate of severe allergic reactions to the Johnson & Johnson vaccine has not been reported as of this article's publication date.3

In all cases, reactions are extremely rare.

3. What allergy-related precautions are healthcare providers taking at vaccine appointments?

The exact details will vary from state to state, city to town, pharmacy to hospital, and so on. However, per CDC guidelines, you can expect the following precautions to be taken at your appointment:5

  • Someone will ask you about your allergies before you are given the shot.
  • After you receive the shot, you will be asked to wait for anywhere from 15 to 30 minutes before leaving.
  • The personnel at the site will be aware of the rare risk of severe allergic reaction and have access to immediate treatment in the form of epinephrine (e.g., prefilled syringe, autoinjector), which they will use if necessary.

Severe allergic reactions to the vaccine can be treated. COVID-19 carries a huge variety of risks that cannot all be easily treated and are not fully understood, including post-COVID conditions like long COVID and multisystem inflammatory syndrome (MIS).6

4. What is the cause of allergic reactions to the COVID-19 vaccines? 

It’s uncertain what exact component is causing allergic reactions to the vaccines. The likely cause in the Pfizer and Moderna vaccines is an organic molecule called polyethylene glycol (PEG).PEG is found in different types of vaccines and medicines, most notably laxatives. If you are allergic to PEG, the CDC recommends that you do not receive the Pfizer nor Moderna vaccines.2

The Johnson & Johnson vaccine contains polysorbate 80, which is structurally similar to PEG and may cause cross-reactivity.7

5. What are the symptoms of an allergic reaction to the COVID-19 vaccine? 

Symptoms can include:4

  • Persistent dry cough
  • Respiratory failure
  • Skin rash
  • Throat swelling 
  • Tongue swelling
  • Vomiting/nausea
  • Watery/swollen eyes
  • Wheezing

It’s OK to be concerned about COVID-19 vaccines and allergies. Bring any questions or concerns you may have to your healthcare provider and consult reputable sources such as the CDC for additional information to help guide your decisions. 

Please note that the COVID-19 situation is evolving every day. For the most up-to-date information, refer to the Centers for Disease Control and Prevention

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  1. Centers for Disease Control and Prevention (CDC). How Do I Find a COVID-19 Vaccine? Retrieved April 2021.
  2. CDC. Information about COVID-19 Vaccines for People with Allergies. Retrieved April 2021.
  3. ACAAI. ACAAI Updates to Guidance on Risk of Allergic Reactions to COVID-19 Vaccines. Retrieved May 2021.
  4. CDC. Allergic Reactions Including Anaphylaxis After Receipt of the First Dose of Moderna COVID-19 Vaccine — United States, December 21, 2020–January 10, 2021. MMWR Morb Mortal Wkly Rep 2021;70:125–129.
  5. CDC. Interim Considerations: Preparing for the Potential Management of Anaphylaxis after COVID-19 Vaccination. Retrieved April 2021.
  6. CDC. Post-COVID Conditions. Retrieved May 2021.
  7. MedPage Today. CDC Staff Teases New Guidance for Those Allergic to COVID Vax. Retrieved May 2021.