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This has been reviewed and updated as of May 25, 2021.
Nearly as soon as the COVID-19 vaccines were granted emergency use authorization in the United States and started rolling out in other countries around the world, questions arose about their link with allergic reactions in some recipients, including anaphylactic (very serious and even life-threatening) reactions.
You may be wondering if you should get the vaccine if you have a history of severe allergic reactions.
With more months of data and many millions of vaccine doses administered, here’s everything we know about the COVID-19 vaccines and the potential for allergic reactions, especially severe reactions like anaphylaxis.
How Common Are Allergic Reactions, Including Anaphylaxis, to the COVID-19 Vaccine?
The answer is reassuring: Allergic reactions are not common and anaphylactic reactions are very rare. Anaphylaxis to the mRNA COVID-19 vaccines, which include those from Moderna and Pfizer, is estimated to occur in 2.5 to 11.1 cases per 1 million doses, mostly in people with a history of allergy, according to a March 2021 study published in the Journal of the American Medical Association (JAMA).
The researchers investigated allergic reactions after more than 60,000 mRNA COVID-19 vaccine administrations. They found that acute allergic reactions were reported in 1,365 individuals overall (2.1 percent). Allergic reactions occurred slightly more frequently with Moderna vaccine patients than Pfizer vaccine patients (2.20 percent versus 1.95 percent).
People with anaphylaxis had an average age of 41 and 94 percent were female. More than 60 percent had an allergy history and 31 percent had an anaphylaxis history. The average time to anaphylaxis onset was 17 minutes. One patient was admitted to intensive care, 56 percent received epinephrine — importantly — and all recovered.
The CDC also published a report of the data they gathered from people who received a Pfizer COVID-19 vaccine between December 14 and 23, 2020. There were 21 cases of anaphylaxis and 83 cases of non-anaphylaxis allergic reaction after administration of 1,893,360 first doses of the Pfizer COVID-19 vaccine.
Anaphylaxis cases
- 86% of anaphylaxis cases had symptom onset within 30 minutes of vaccination
- 81% anaphylaxis cases of had a history of allergies or allergic reactions, including some with previous anaphylaxis events
- 90% of anaphylaxis cases were treated with epinephrine as part of therapy and no deaths have been reported
Non-anaphylaxis cases
- 87% of non-anaphylactic cases were classified as nonserious
- 85% of non-anaphylactic cases had a symptom onset within 30 minutes of vaccination
- 67% non-anaphylactic cases had a past history of allergies or allergic reactions
In a review of Vaccine Adverse Event Reporting System (VAERS) data, researchers found that there have been only four confirmed cases of anaphylaxis among people who received the Johnson & Johnson vaccination, which equates to fewer than 0.5 cases per 1 million doses administered (four reports remain under review), per a May 2021 review in the CDC’s Morbidity and Mortality Weekly Report (MMWR).
Is a COVID-19 Vaccine Riskier Than Other Kinds of Vaccines?
In general, allergic reactions to vaccines in general are rare — in fact, anaphylaxis occurs in an estimated 1.31 in 1 million doses given, per the American College of Allergy, Asthma & Immunology (ACAAI). With influenza vaccines, anaphylaxis has been reported at a rate of one in 1 million or less, per Vanderbilt University Medical Center.
The rate of anaphylaxis in the Johnson & Johnson COVID-19 vaccine appears to be lower than this. And although the COVID-19 anaphylaxis rate for the Pfizer and Moderna vaccines is currently slightly higher (with 2.5 to 11.1 cases per 1 million doses), it’s too early to draw any major conclusions or comparisons.
For example, in its analysis of initial Pfizer vaccine data, the CDC warned that it’s possible that “intense media attention around the national COVID-19 vaccination program and heightened awareness of reports of anaphylaxis have affected vaccine recipient and health care provider behavior and practices, including elevated concern and anxiety, higher index of suspicion for anaphylaxis, and lower threshold for early treatment of suspected cases, thereby resulting in an increase in diagnosis of suspected anaphylaxis.”
The CDC’s report also concludes with this important statement: “Mortality [death] from COVID-19 in populations at high risk is substantial and treatment options are limited. Widespread vaccination against COVID-19 with highly effective vaccines represents an important tool in efforts to control the pandemic. CDC and FDA will continue to monitor for adverse events, including anaphylaxis, after receipt of COVID-19 vaccines and will regularly assess the benefits and risks of vaccination.”
Why Can the COVID-19 Vaccine Cause an Allergic Reaction?
Polyethylene glycol (PEG) is an ingredient in the Pfizer and Moderna vaccines known to cause allergic reactions (although rarely). It is also found in laxatives and bowel preps for colonoscopies and is also sometimes used as a stabilizer in vaccines.
The ACAAI has also warned about issues for people with a history of allergies to polysorbate or polyoxyl 35 castor oil (e.g. paclitaxel), because these may cross-react with PEG.
The Johnson & Johnson vaccine contains polysorbate, but not polyethylene glycol.
Can You Get a COVID-19 Vaccine If You Have a History of Allergic Reactions?
The short answer is probably, but with caution. Here’s the latest information, based on the type of allergic reactions you’ve had in the past.
If You’ve Had an Allergic Reaction to a Previous COVID-19 Vaccine or Its Ingredients
The current CDC guidance says that people who meet the following criteria should not get the COVID-19 vaccine at this time:
- Severe allergic reaction (e.g., anaphylaxis) after a previous dose or to a component of the COVID-19 vaccine
- Immediate allergic reaction of any severity to a previous dose or known (diagnosed) allergy to a component of the vaccine
The CDC says: “People with a contraindication to one type of the currently authorized COVID-19 vaccines (e.g., mRNA) have a precaution to the other (e.g., Janssen viral vector). However, because of potential cross-reactive hypersensitivity between ingredients in mRNA and Janssen COVID-19 vaccines, consultation with an allergist-immunologist should be considered to help determine if the patient can safely receive vaccination.”
Ingredients in the COVID-19 Vaccines
Here are the ingredients in the Pfizer-BioNTech vaccine, according to the fact sheet from the U.S. Food and Drug Administration (FDA).
- mRNA
- Lipids ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate), 2 [(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 1,2-Distearoyl-sn-glycero-3- phosphocholine, and cholesterol)
- Potassium chloride
- Monobasic potassium phosphate
- Sodium chloride
- Dibasic sodium phosphate dihydrate
- Sucrose
Here are the ingredients in the Moderna vaccine, according to the fact sheet from the FDA.
- mRNA
- Lipids (SM-102, polyethylene glycol [PEG] 2000 dimyristoyl glycerol [DMG], cholesterol, and 1,2-distearoyl-sn-glycero-3-phosphocholine [DSPC])
- Tromethamine
- Tromethamine hydrochloride
- Acetic acid
- Sodium acetate trihydrate
- Sucrose
Here are the ingredients in the Johnson & Johnson vaccine, according to the fact sheet from the FDA.
- Recombinant
- Replication-incompetent adenovirus type 26 expressing the SARS-CoV-2 spike protein
- Citric acid monohydrate
- Trisodium citrate dihydrate
- Ethanol
- 2-hydroxypropyl-β-cyclodextrin (HBCD)
- Polysorbate-80
- Sodium chloride
If You Have a History of Allergic Reactions to Other Vaccines or Infused or Injectable Medication
If you’ve had an immediate allergic reaction to an infused or injectable medication — such as a biologic for an inflammatory or autoimmune disease — you should consider it a precaution to the vaccine and discuss it with your doctor.
The CDC says: “These persons should be counseled about the unknown risks of developing a severe allergic reaction and balance these risks against the benefits of vaccination.”
The ACAAI says to consider these questions:
- Do you have a history of severe allergic reaction to an injectable medication (intravenous, intramuscular, or subcutaneous)?
- Do you have a history of a severe allergic reaction to a prior vaccine?
- Do you have a history of a severe allergic reaction to polyethylene glycol (PEG), a polysorbate or polyoxyl 35 castor oil (e.g. paclitaxel) containing injectable or vaccine?
The ACAAI states that if you answer yes to any of these questions, you should speak to a board-certified allergy and asthma doctor before getting the vaccine.
Keep in mind that there’s a difference between having an allergic reaction to an infused or injectable medication and a side effect of the medication.
“We need to determine if a patient has had an anaphylactic reaction to an infused or injected medication. They should likely avoid COVID-19 vaccines for now. For people with milder reactions, it is more of a risk versus benefit decision-making process,” says Nilanjana Bose, MD, a board-certified rheumatologist with the Rheumatology Center of Houston.
If you’re not sure whether your side effects after receiving an infused or injected medication are considered an allergic reaction, ask your doctor.
The CDC is NOT saying that all people who have had allergic reactions to infused or injectable medications should not get a COVID-19 vaccine — just that it’s a good idea to speak with your doctor to review your medical history and make sure it’s safe to get the vaccine.
Read more here about what to know if you have a history of allergies to infused or injectable medications.
If You Have a History of Allergic Reactions to Food, Pets, or Other Environmental Triggers
The CDC says that a history of allergic reactions, even severe reactions, to food, pets, venom, latex, or other environmental triggers is not a contraindication to getting a COVID-19 vaccine. A contraindication is issued when a vaccine may greatly increase a person’s risks of adverse effects due to an existing condition.
This means you can get a COVID-19 vaccine if you have a history of allergies to these things, although of course you should ask your doctor if you have any specific concerns or questions.
“Individuals with common allergies like those to foods, medications, environmental factors, venom, and latex are no more likely to have an anaphylactic reaction than the general public,” says Robyn J. Kreiner, MD, a board-certified allergist and immunologist at Strauss Allergy & Asthma in Long Island, New York.
Should Everyone Be Monitored After Receiving the COVID-19 Vaccine?
Yes, whether or not you have had allergic reactions in the past. The CDC states that you should be observed for 15 minutes by your vaccine provider to make sure you don’t have an adverse reaction.
Those who have a history of anaphylaxis due to any cause need to be monitored for 30 minutes after vaccination. You should also be monitored for 30 minutes if there are any concerns about your being at increased risk of having an allergic reaction.
Recognizing Allergic Reactions to a COVID-19 Vaccine
It’s important to distinguish side effects from the vaccine from allergic reactions to it. Most people who get the vaccine experience some common side effects. These include pain at the injection site, fatigue, headache, muscle pain, chills, joint pain, and fever.
“The common side effects of these vaccines are very common to other vaccines,” says Dr. Kreiner. “And like other vaccines, the symptoms do self-resolve.”
Allergic reactions to the COVID-19 vaccine would generally fall into one of two categories: non-severe immediate reactions and severe reactions, per the CDC.
Non-severe reactions that occur within four hours of getting vaccinated are known as immediate allergic reactions. Symptoms include:
- Hives
- Swelling
- Wheezing
Severe allergic reactions require treatment with epinephrine or an EpiPen, or treatment at a hospital, according to the CDC. This is also known as anaphylaxis. Symptoms include:
- Hives
- Low blood pressure
- Constriction of airways
- Wheezing (respiratory distress)
- Swollen tongue or throat
- A weak and rapid pulse
- Nausea, vomiting, or diarrhea
- Loss of consciousness
The Importance of Getting the COVID-19 Vaccine
The criteria for people who should not get a COVID-19 vaccine is very narrow. The CDC is saying that people who have had a severe allergic reaction to a previous dose of a COVID-19 vaccine should not receive another dose, for now (though their doctor may say they can receive the Johnson & Johnson vaccine after a first dose of an mRNA vaccine).
But for everyone else — including people who had non-anaphylactic allergic reactions to a COVID-19 vaccine, people who have allergies to ingredients in the COVID-19 vaccine, and people who have had allergic reactions to infused or injectable medications — the vaccine may be given, but it’s important to discuss this with your doctor and make sure the vaccine can be given in a safe environment. This means making sure the person can be observed for 30 minutes afterward and medical care is available.
It may seem concerning that some people have had allergic reactions to the vaccine, but keep in mind that the number of reactions is very small in comparison to the total amount of vaccines administered.
And most important: “The overall statement that people should be aware of is that the benefits of getting the COVID-19 vaccine far outweigh the risks of the possible chance of an anaphylactic reaction to the vaccine,” says Dr. Kreiner.
If you’re worried about potential allergic reactions to the COVID-19 vaccine, the best course of action is to speak to your doctor about any previous allergic reactions you’ve had.
Your physician can then compare what you’ve had prior reactions to with the list of ingredients in the vaccines.
“If it’s the case that there’s no connection between those, then I think you’re probably going to be okay to get the vaccination,” says infectious disease physician Amesh A. Adalja, MD, a Senior Scholar at Johns Hopkins Center for Health Security. “If there is a connection, then you have to think about the risks and benefits of getting the vaccine, and wait around for 30 minutes afterward to make sure you don’t have a reaction.”
What If You’re Immunocompromised?
The COVID-19 vaccines currently authorized for use in the United States are not live vaccines, and they can be given to immunocompromised patients.
However, talk to your doctor about what this means for your COVID-19 mitigation efforts moving forward. There’s a possibility of a diminished immune response to the vaccine in immunocompromised patients, and experts still don’t know how those with weakened immune systems will respond to the vaccine.
“It’s recommended that immunocompromised patients get this vaccine,” says Dr. Kreiner. Experts believe that some protection is better than none when it comes to COVID-19.
If you’re immunocompromised, you should inform your vaccination provider. In fact, before you get the COVID-19 vaccine, the FDA says you should tell your vaccination provider about all of your medical conditions, including if you:
- Are immunocompromised or taking medicine that affects your immune system
- Have any allergies
- Have a fever
- Have a bleeding disorder or are on a blood thinner
- Are pregnant or plan to become pregnant
- Are breastfeeding
- Have received another COVID-19 vaccine
“Immunocompromised individuals may have to consider themselves at higher risk for severe COVID-19, and this vaccine is one way to mitigate that risk,” says Dr. Adalja. “Because of that, I think that the risk-benefit ratio favors the use of this vaccine even more so in immunocompromised individuals than in the general population.”
Also keep in mind that we’re still learning about the long-term effects of COVID-19, but if you stay on site after your vaccination is given, allergic reactions can be treated.
“Anaphylaxis is very treatable, but we don’t have a standard treatment for COVID-19 and there are many new symptoms patients are manifesting that we still are figuring out,” says Dr. Kreiner.
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ACAAI Updates to Guidance on Risk of Allergic Reactions to COVID-19 Vaccines. American College of Allergy, Asthma & Immunology. April 26, 2021. https://acaai.org/news/acaai-updates-guidance-risk-allergic-reactions-covid-19-vaccines
ACAAI Guidance on Risk of Allergic Reactions to mRNA COVID-19 Vaccines. American College of Allergy, Asthma & Immunology. March 8, 2021. https://college.acaai.org/acaai-guidance-on-risk-of-allergic-reactions-to-mrna-covid-19-vaccines-2/
Blumenthal KG, et al. Acute Allergic Reactions to mRNA COVID-19 Vaccines. Journal of the American Medical Association. March 8, 2021. doi: https://www.doi.org/10.1001/jama.2021.3976
CDC COVID-19 Response Team; Food and Drug Administration. Allergic Reactions Including Anaphylaxis After Receipt of the First Dose of Pfizer-BioNTech COVID-19 Vaccine — United States, December 14–23, 2020. Morbidity and Mortality Weekly Report. January 15, 2021. doi: http://doi.org/10.15585/mmwr.mm7002e1
Coronavirus (COVID-19) Information for Employees and Patients. Vanderbilt University Medical Center. Accessed December 17, 2020. https://www.vumc.org/coronavirus/common-questions-about-covid-vaccines-and-allergies
COVID-19 Vaccines and Allergic Reactions. U.S. Centers for Disease Control and Prevention. March 4, 2021. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/allergic-reaction.html
Fact Sheet for Recipients and Caregivers. Emergency Use Authorization (EUA) of The Janssen COVID-19 Vaccine to Prevent Coronavirus Disease 2019 (COVID-19) in Individuals 18 Years of Age and Older. Food and Drug Administration. April 23, 2021. https://www.fda.gov/media/146305/download
Fact Sheet for Recipients and Caregivers. Emergency Use Authorization (EUA) of the Moderna COVID-19 Vaccine to Prevent Coronavirus Disease 2019 (COVID-19) in Individuals 18 Years of Age and Older. U.S. Food and Drug Administration. December 2020. https://www.fda.gov/media/144638/download
Fact Sheet for Recipients and Caregivers. Emergency Use Authorization (EUA) of The Pfizer-BioNTech COVID-19 Vaccine to Prevent Coronavirus Disease 2019 (COVID-19). Food and Drug Administration. https://www.fda.gov/media/144414/download
Interim Clinical Considerations for Use of Pfizer-BioNTech COVID-19 Vaccine. Vaccines & Immunizations. U.S. Centers for Disease Control and Prevention. May 14, 2021. https://www.cdc.gov/vaccines/covid-19/info-by-product/pfizer/clinical-considerations.html
Interview with Amesh A. Adalja, MD, an infectious disease physician and senior scholar at Johns Hopkins Center for Health Security
Interview with Nilanjana Bose, MD, a board-certified rheumatologist with the Rheumatology Center of Houston
Interview with Robyn J. Kreiner, MD, a board-certified allergist and immunologist at Strauss Allergy & Asthma in Long Island, New York
Shay DK, et al. Safety Monitoring of the Janssen (Johnson & Johnson) COVID-19 Vaccine — United States, March–April 2021. Morbidity and Mortality Weekly Report. U.S. Centers for Disease Control and Prevention. May 7, 2021. doi: http://doi.org/10.15585/mmwr.mm7018e2