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On December 19th - following reports of a very small number allergic reactions among recipients of the COVID-19 vaccine (see Reuters report FDA investigating five allergic reactions after Pfizer shot in U.S.), the CDC published an initial Statement On COVID-19 Vaccines and Severe Allergic Reactions.
The primary contraindications offered at the time were:
If you have ever had a severe allergic reaction to any ingredient in a COVID-19 vaccine, CDC recommends that you should not get that specific vaccine. If you have had a severe allergic reaction to other vaccines or injectable therapies, you should ask your doctor if you should get a COVID-19 vaccine. Your doctor will help you decide if it is safe for you to get vaccinated.
CDC recommends that people with a history of severe allergic reactions not related to vaccines or injectable medications—such as allergies to food, pet, venom, environmental, or latex—may still get vaccinated. People with a history of allergies to oral medications or a family history of severe allergic reactions, or who might have an milder allergy to vaccines (no anaphylaxis)—may also still get vaccinated.
If you have a severe allergic reaction after getting the first shot, you should not get the second shot. Your doctor may refer you to a specialist in allergies and immunology to provide more care or advice.
Since then, a second (Moderna) vaccine has come online, and more reports of allergic reactions have come in, prompting new, somewhat stricter guidelines, to be issued.
As we've discussed previously, the rolling out of a national vaccine campaign in the midst of a pandemic is a logistical nightmare and all cannot be expected to go smoothly. The fact that we have a coronavirus vaccine at all, in less than a year, is a bit of a miracle.
On Wednesday of this week the CDC published revised guidance (see Interim Clinical Considerations for Use of mRNA COVID-19 Vaccines Currently Authorized in the United States) designed primarily for clinicians, public health workers, and those involved it the vaccine rollout that covers a number of concerns, including:
Summary of recent changes (last updated December 30, 2020):
- Additional information on antibody therapies and COVID-19 vaccination
- Information on COVID-19 vaccination and outbreak management
- Additional information on vaccination of immunocompromised persons
- Updates to contraindications and precautions to vaccination
- Information on COVID-19 vaccination and tuberculin skin testing
Included are updated contraindications for receiving the COVID-19 vaccine.
Recommendations for contraindications and precautions are described below and summarized in Appendix A. The following recommendations may change as further information becomes available.
Contraindications
CDC considers a history of the following to be a contraindication to vaccination with both the Pfizer-BioNTech and Moderna COVID-19 vaccines:* These persons should not receive mRNA COVID-19 vaccination at this time unless they have been evaluated by an allergist-immunologist and it is determined that the person can safely receive the vaccine (e.g., under observation, in a setting with advanced medical care available). See Appendix B for more information on ingredients included in mRNA COVID-19 vaccines.
- Severe allergic reaction (e.g., anaphylaxis) after a previous dose of an mRNA COVID-19 vaccine or any of its components
- Immediate allergic reaction of any severity to a previous dose of an mRNA COVID-19 vaccine or any of its components (including polyethylene glycol [PEG])*
- Immediate allergic reaction of any severity to polysorbate (due to potential cross-reactive hypersensitivity with the vaccine ingredient PEG)*
Persons with an immediate allergic reaction to the first dose of an mRNA COVID-19 vaccine should not receive additional doses of either of the mRNA COVID-19 vaccines. Providers should attempt to determine whether reactions reported following vaccination are consistent with immediate allergic reactions versus other types of reactions commonly observed following vaccination, such as a vasovagal reaction or post-vaccination side effects (which are not contraindications to receiving the second vaccine dose) (Appendix C).
Yesterday the CDC also updated their advice for the general public in light of these new guidelines.
COVID-19 Vaccines and Allergic Reactions
Updated Dec. 31, 2020
This webpage provides recommendations on what to do if you experience an allergic reaction after getting a COVID-19 vaccination. It also provides recommendations for people who have had allergic reactions to other vaccines and for those with other types of allergies.
This page will be updated when we get new information.
If you get a COVID-19 vaccine and you think you might be having a severe allergic reaction after leaving the vaccination site, seek immediate medical care by calling 911.
If you have a severe allergic reaction to a COVID-19 vaccine
CDC has learned of reports that some people have experienced severe allergic reactions—also known as anaphylaxis—after getting a COVID-19 vaccine. As an example, an allergic reaction is considered severe when a person needs to be treated with epinephrine or EpiPen© or if they must go to the hospital.
If you have had a severe allergic reaction to any ingredient in an mRNA COVID-19 vaccine, you should not get either of the currently available mRNA COVID-19 vaccines. If you had a severe allergic reaction after getting the first dose of an mRNA COVID-19 vaccine, CDC recommends that you should not get the second dose.
If you have a non-severe allergic reaction to a COVID-19 vaccine
CDC has also learned of reports that some people have experienced non-severe allergic reactions within 4 hours after getting vaccinated (known as immediate allergic reactions), such as hives, swelling, and wheezing (respiratory distress).
If you have had an immediate allergic reaction—even if it was not severe—to any ingredient in an mRNA COVID-19 vaccine, CDC recommends that you should not get either of the currently available mRNA COVID-19 vaccines. If you had an immediate allergic reaction after getting the first dose of an mRNA COVID-19 vaccine, you should not get the second dose. Your doctor may refer you to a specialist in allergies and immunology to provide more care or advice.
If you have had an allergic reaction to other types of vaccines
If you have had an immediate allergic reaction—even if it was not severe—to a vaccine or injectable therapy for another disease, ask your doctor if you should get a COVID-19 vaccine. Your doctor will help you decide if it is safe for you to get vaccinated.
If you have allergies not related to vaccines
CDC recommends that people with a history of severe allergic reactions not related to vaccines or injectable medications—such as food, pet, venom, environmental, or latex allergies—get vaccinated. People with a history of allergies to oral medications or a family history of severe allergic reactions may also get vaccinated.
If you have had an allergic reaction to polyethylene glycol (PEG) or polysorbate
These recommendations include allergic reactions to PEG and polysorbate. Polysorbate is not an ingredient in either mRNA COVID-19 vaccine but is closely related to PEG, which is in the vaccines. People who are allergic to PEG or polysorbate should not get an mRNA COVID-19 vaccine.
Safeguards Are in Place
CDC has provided recommendations for COVID-19 vaccination providers about how to prepare for the possibility of a severe allergic reaction:
Learn more about what to expect after getting vaccinated for COVID-19, including normal side effects and tips to reduce pain or discomfort.
- All people who get a COVID-19 vaccine should be monitored on site. People who have had severe allergic reactions or who have had any type of immediate allergic reaction to a vaccine or injectable therapy should be monitored for at least 30 minutes after getting the vaccine. All other people should be monitored for at least 15 minutes after getting the vaccine.
- Vaccination providers should have appropriate medications and equipment—such as epinephrine, antihistamines, stethoscopes, blood pressure cuffs, and timing devices to check your pulse—at all COVID-19 vaccination sites.
- If you experience a severe allergic reaction after getting a COVID-19 vaccine, vaccination providers should provide rapid care and call for emergency medical services. You should continue to be monitored in a medical facility for at least several hours.
CDC Is Monitoring Reports of Severe Allergic Reactions
If someone has a severe allergic reaction after getting vaccinated, their vaccination provider will send a report to the Vaccine Adverse Event Reporting System (VAERS).external icon VAERS is the national system that collects reports from healthcare professionals, vaccine manufacturers, and the public about adverse events that happen after vaccination. Reports of adverse events that are unexpected, appear to happen more often than expected, or have unusual patterns are followed up with specific studies.
Learn more about how federal partners are monitoring the safety of COVID-19 vaccines in the United States.
As we've discussed previously, the rolling out of a national vaccine campaign in the midst of a pandemic is a logistical nightmare and all cannot be expected to go smoothly. The fact that we have a coronavirus vaccine at all, in less than a year, is a bit of a miracle.
In addition to a small number of allergic reactions - we've also seen a few high profile dosing and medication errors (see ABC news report 42 people in West Virginia mistakenly given Regeneron antibody treatment instead of the coronavirus vaccine). 
These are admittedly isolated incidents - and so far no one appears to have been harmed - but these are the sort of headlines that can erode the public's confidence in the vaccine. Hopefully things will go smoother in the new year.
For clinicians looking for more information on managing allergic reactions with the COVID-19 vaccine, last week's COCA Call (COVID-19 Vaccines: Update on Allergic Reactions, Contraindications, and Precautions) is now available online.
