What about the reports of allergic reactions/anaphylaxis? (Updated*)

Pfizer-BioNTech and Moderna Vaccines

Despite there being no reports of anaphylaxis in clinical trials, there have been anaphylaxis reactions reported since widespread distribution – something that is expected when vaccination on a large scale.

During December 14-23, 2020, monitoring by the Vaccine Adverse Event Reporting System (VAERS) detected 21 cases of anaphylaxis after administration of a reported 1,893,360 first doses of the Pfizer-BioNTech Covid vaccine (11.1 cases per million doses); about 10 times the rate of anaphylaxis after the flu vaccine (1.3 cases per million). Seventeen of these cases occurred in persons with a documented history of allergies or allergic reactions, seven of whom had a history of anaphylaxis. 71% of the anaphylaxis occurred of these occurred within 15 minutes. Of the remaining case reports that were determined not to be anaphylaxis, 86 were judged to be nonanaphylaxis allergic reactions, and 61 were considered nonallergic adverse events. Seven case reports were still under investigation.

From December 21, 2020–January 10, 2021, monitoring by the VAERS detected 10 cases of anaphylaxis after administration of a reported 4,041,396 first doses of Moderna COVID-19 vaccine (2.5 cases per million doses administered). In nine cases, onset occurred within 15 minutes of vaccination. No anaphylaxis-related deaths were reported.


At this time, the following are contraindications from receiving either PfizerBioNTech or Moderna vaccine:

  • 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)*

* These persons should not receive mRNA COVID-19 vaccination (Pfizer-BioNTech or Moderna) 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).


The CDC considers a history of any immediate allergic reaction to any other vaccine or injectable therapy (i.e., intramuscular, intravenous, or subcutaneous vaccines or therapies [excluding subcutaneous immunotherapy for allergies , i.e. “allergy shots”] not related to a component of mRNA COVID-19 vaccines or polysorbate) as a precaution but not a contraindication to vaccination for both the Pfizer-BioNTech and Moderna COVID-19 vaccines. This includes persons with a reaction to a vaccine or injectable therapy that contains multiple components, one of which is PEG, another vaccine component, or polysorbate, but in whom it is unknown which component elicited the immediate allergic reaction.

Neither Contraindications or Precautions

  • Allergic reactions (including severe allergic reactions) not related to vaccines, injectable therapies, components of mRNA COVID-19 vaccines (including PEG), or polysorbates, such as allergic reactions related to food, pet, venom, or environmental allergies, or allergies to oral medications (including the oral equivalents of injectable medications) are not a contraindication or precaution to vaccination with either mRNA COVID-19 vaccine.
  • The vial stoppers of these mRNA vaccines are not made with natural rubber latex, and there is no contraindication or precaution to vaccination for persons with a latex allergy.
  • Because the mRNA COVID-19 vaccines do not contain eggs or gelatin, persons with allergies to these substances do not have a contraindication or precaution to vaccination.
  • Persons with only a delayed-onset local reaction (e.g., erythema, induration, pruritus) around the injection site area after the first vaccine dose do not have a contraindication or precaution to the second dose.

Vaccine providers should observe patients after vaccination to monitor for the occurrence of immediate adverse reactions:

  • Persons with a history of anaphylaxis: 30 minutes.
  • All other persons: 15 mins. Appropriate medical treatment used to manage immediate allergic reactions must be immediately available in the event an acute anaphylactic reaction occurs following administration of the vaccine.

Johnson & Johnson Vaccine

In the clinical trial, urticaria (all non-serious) was rare, being reported in five vaccinated individuals and 1 individual who received placebo in the 7 days following vaccination. In addition, a serious adverse event of hypersensitivity, not classified as anaphylaxis, was reported in 1 vaccinated individual with urticaria beginning two days following vaccination and angioedema of the lips with no respiratory distress beginning four days following vaccination. The event was likely related to the vaccine.

Severe allergic reactions, including one case of anaphylaxis in an ongoing open-label study in South Africa, have been reported following the vaccine administered in clinical studies.


Updated: March 1, 2021