It’s Safe to Receive Your Second COVID-19 Vaccine After an Allergic Reaction, Study Finds


A study published in JAMA Internal Medicine explained that a first dose reaction to COVID-19 vaccination should not deter people from receiving their second dose.


A study conducted by allergists at Massachusetts General Hospital analyzed data from multiple hospitals of individuals who had allergic reaction responses to their first dose of a COVID-19 vaccine. Of all the patients studied, there were no reports of complications related to receiving the second vaccine dose.

Allergic reactions after mRNA COVID-19 vaccinations have been reported in as high as 2% of individuals. Anaphylaxis, a possibly fatal allergic reaction, occurred in up to 2.5 of 10,000 people. In evaluating the safety of receiving a second dose for said patients after a previous reaction to the first dose, MGH, Vanderbilt University Medical Center, University of Texas Southwestern Medical Center and Yale School of Medicine combined data in those who had an allergy reaction.

Symptoms after the first dose of the vaccine included itching, hives, or flushing. The study included 189 participants, of whom 32 experienced severe reaction in anaphylaxis. In total, 159 patients received the second dose. All participants, including those with severe allergic reaction, tolerated the second dose of the vaccine. Of those that received the second dose, 32 reported mild symptoms.

However, co–senior author Kimberly G. Blumenthal, MD, MSc, co-director of the Clinical Epidemiology Program within MGH’s Division of Rheumatology, Allergy and Immunology noted that immediate reaction from the vaccine may not be an allergy reaction, but rather hypersensitivity or Ig-E-mediated hypersensitivity. This is because with classic allergy, re-exposure causes the same or worse symptoms, which is not the case with the second dose of vaccine in these cases.

The study’s findings show that it is safe for most people to receive a second dose of the mRNA COVID-19 vaccine, according to co–senior author Aleena Banerji, MD, clinical director of the Allergy and Clinical Immunology Unit at MGH. “After first dose reactions, allergy specialists may be useful to help guide risk/benefit assessments and assist with completion of safe vaccination,” she said.1


  1. Second COVID-19 mRNA vaccine dose found safe following allergic reactions to first dose. News Release. Massachusetts General Hospital; July 26, 2021. Accessed August 11, 2021.
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