Relationship between pre-existing allergies and anaphylactic reactions post mRNA COVID-19 vaccine administration

Vaccine. 2021 Jul 22;39(32):4407-4409. doi: 10.1016/j.vaccine.2021.06.058. Epub 2021 Jun 23.


Two mRNA vaccines for COVID-19, Pfizer-BioNTech and Moderna, are approved for emergency use in the United States. After their approval and dosing in millions of recipients, reports of anaphylaxis began to appear in the Vaccine Adverse Reporting System (VAERS). Here we provide an analysis of the relationship between prior history of allergy and/or anaphylaxis and anaphylaxis rates following the administration of mRNA COVID-19 vaccines. Overall reported incidence of anaphylaxis was estimated to be rare at 4.2 cases per million doses. It appeared that the relative incidence of anaphylaxis following administration of these COVID-19 vaccines was two and seven times higher for recipients with a prior history of allergies and/or anaphylaxis, respectively. This report provides valuable metrics to make evidence-based decisions for subjects with pre-existing allergic conditions receiving a COVID-19 mRNA vaccine.

Keywords: Anaphylaxis following COVID-19 vaccine; COVID-19; mRNA vaccine.

MeSH terms

  • Anaphylaxis* / chemically induced
  • Anaphylaxis* / epidemiology
  • COVID-19 Vaccines
  • COVID-19*
  • Humans
  • RNA, Messenger / genetics
  • SARS-CoV-2
  • United States / epidemiology
  • Vaccines* / adverse effects


  • COVID-19 Vaccines
  • RNA, Messenger
  • Vaccines