Acute Allergic Reactions to mRNA COVID-19 Vaccines | Allergy and Clinical Immunology | JAMA | JAMA Network
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Shimabukuro  TT, Cole  M, Su  JR.  Reports of anaphylaxis after receipt of mRNA COVID-19 vaccines in the US—December 14, 2020-January 18, 2021.   JAMA. Published online February 12, 2021. doi:10.1001/jama.2021.1967PubMedGoogle Scholar
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    4 Comments for this article
    Overlapping 95% CIs
    Jean-Francois Grenier, MD | Private
    With overlapping 95% CIs, I'm a little surprised to read that "Acute allergic reactions were reported by 1365 employees overall (2.10% [95% CI, 1.99%-2.22%]), more frequently with the Moderna vaccine compared with Pfizer-BioNTech (2.20% [95% CI, 2.06%-2.35%] vs 1.95% [95% CI, 1.79%-2.13%]", regardless of the p value level of 0.03.
    Did They Get A Second Dose?
    Judy Malmgren, PhD Epidemiology | University of Washington, Department of Epidemiology
    Did the persons that reported non-anaphylactic allergic reactions get their second dose and if so did they have the same reaction? If they got the second dose did they pre-load with antihistamine? Very important information for 2% of the US population which is 6,620,000 people.
    Acute Allergic Reactions to mRNA COVID-19 Vaccines
    Sandro Tsang, Tutor | People's Open Access Education Initiative
    Evidence about side-effects are rarely available. I hope similar studies will be conduct with individuals who are immunocompromised. Right now, governments give those people priorities to receive the vaccines. We really do not know how safe the vaccines are to those individuals.
    Overlapping 95% CIs - Noteable
    Nicholas Kottenstette, PhD | Private
    There is a weak indication of increased relative risk, 1.13 (1.01, 1.26) 95%CI with a p = 0.028 for recipients of the Moderna vaccine as the authors correctly noted. Interestingly, there are 191 reports of anaphylaxis for Pfizer-BioNTech as compared to 101 for Moderna on VAERS as of 03/05/2021 (1). Does anyone know how many vaccinations have been administered for each brand?


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    Research Letter
    March 8, 2021

    Acute Allergic Reactions to mRNA COVID-19 Vaccines

    Author Affiliations
    • 1Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, Boston
    • 2Department of Emergency Medicine, Massachusetts General Hospital, Boston
    • 3Division of Infectious Diseases, Massachusetts General Hospital, Boston
    • 4Department of Emergency Medicine, Brigham and Women’s Hospital, Boston, Massachusetts
    • 5Division of Allergy and Clinical Immunology, Brigham and Women’s Hospital, Boston, Massachusetts
    JAMA. Published online March 8, 2021. doi:10.1001/jama.2021.3976

    Anaphylaxis to the mRNA COVID-19 vaccines is currently estimated to occur in 2.5 to 11.1 cases per million doses, largely in individuals with a history of allergy.1 Allergic concerns contribute to vaccine hesitancy; we investigated acute allergic reaction incidence after more than 60 000 mRNA COVID-19 vaccine administrations.

    We prospectively studied Mass General Brigham (MGB) employees who received their first dose of an mRNA COVID-19 vaccine (12/16/2020-2/12/2021, with follow-up through 2/18/2021) (eMethods in the Supplement). For 3 days after vaccination, employees completed symptom surveys through a multipronged approach including email, text message, phone, and smartphone application links. Acute allergic reaction symptoms solicited included itching, rash, hives, swelling, and/or respiratory symptoms (eAppendix in the Supplement).