The COVID-19 Task Force does not anticipate any contraindication for patients on allergen immunotherapy (AIT). However, it would be best to not get the two shots within 48 hours of each other to avoid confusion should a reaction occur.

An NIAID clinical trial is underway to study allergic reactions to the Moderna and Pfizer-BioNTech COVID-19 vaccines.

Managing severe reactions to mRNA COVID 19 vaccines

The CDC has updated their guidance on administration of the SARS-CoV-2 mRNA vaccines with respect to pre-vaccine risks and post-vaccine reactions:

  • The CDC has provided the following differentiation:
  • Contraindication: Persons with a known (diagnosed) allergy to PEG or polysorbate have a contraindication to vaccination.
  • Precaution: Persons with a reaction to a vaccine or injectable therapy that contains multiple components, one of which is PEG, another mRNA vaccine component or polysorbate, but in whom it is unknown which component elicited the immediate allergic reaction have a precaution (counseling, 30-minute observation). Deferral of vaccination and/or consultation with an allergist may be considered. (Pfizer-BioNTech, Moderna)
  • Immediate allergic reaction is defined as any hypersensitivity-related signs or symptoms such as urticaria, angioedema, respiratory distress (e.g., wheezing, stridor), or anaphylaxis that occur within four hours following administration.
  • Individuals with a history of immediate allergic reaction to any component of an mRNA COVID-19 vaccine should not be vaccinated 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).
  • Individuals with an immediate allergic reaction to the first dose of an mRNA vaccine should not receive additional doses of either of the mRNA COVID-19 vaccines.
  • Individuals with a history of food, pet, insect, venom, environmental or latex allergies are able to proceed with vaccination with a standard 15 minute observation period.
    • Vial stoppers of mRNA vaccines are not made with natural rubber latex
    • The mRNA vaccines do not contain egg or gelatin
  • Those with a history of severe allergic reaction (e.g. anaphylaxis) to an injectable medication should use caution when receiving the vaccine and follow a 30-minute observation period.
  • These articles provide additional information on reactions:
    • Maintaining Safety with SARS-CoV-2 Vaccines (NEJM, December 30)
    • Allergic Reactions Including Anaphylaxis after Receipt of the First Dose of Pfizer-BioNTech COVID-19 Vaccine – United States, December 14-23, 2020 (MMWR, January 6)
    • Allergic Reactions Including Anaphylaxis After Receipt of the First Dose of Moderna COVID-19 Vaccine – United States, December 21, 2020 – January 10, 2021 (MMWR, January 29)
    • Allergic Reactions Including Anaphylaxis After Receipt of the First Dose of Pfizer-BioNTech COVID-19 Vaccine (JAMA, January 21)
  • There are multiple systems for monitoring adverse reactions to the COVID-19 vaccine (December 10, 2020)
Vaccine safety
  • Results of safety monitoring from VAERS and Vsafe after one month of vaccinations show over 90% of reactions were non-serious. Anaphylaxis rates (4.5 per million doses) remain in range of other vaccines. Female gender may be a risk factor for adverse reactions and anaphylaxis. (MMWR, February 26)
  • A January 27 update from ACIP shows 50 cases of anaphylaxis following administration of the Pfizer BioNTech vaccine, after 10 million doses (5 per million) and 21 cases following administration of the Moderna vaccine (2.8 per million).
  • There have now been reports of 196 deaths temporally associated with vaccination, 113 after Pfizer and 83 after Moderna; 66% were residents of long-term care facilities (LTCFs). Estimates of background mortality in LTCFs indicate an expected 11,440 deaths following vaccination. Mortality, then, was actually lower for vaccinated residents.
  • Bottom line: This vaccine is very safe, and severe allergic reactions are very rare.