Allergic reactions and adverse events associated with administration of mRNA-based vaccines. A health-care system experience

Background: Adverse reactions, including anaphylaxis, to messenger RNA coronavirus disease 2019 (COVID-19) vaccines rarely occur. Because of the need to administer a timely second dose in subjects who reported a reaction to their first dose, a panel of health-care professionals developed a safe triage of the employees and health care providers (EHCP) at a large health-care system to consider administration of future dosing. Methods: There were 28,544 EHCPs who received their first dose of COVID-19 vaccines between December 15, 2020, and March 8, 2021. The EHCPs self-reported adverse reactions to a centralized COVID-19 command center (CCC). The CCC screened and collected information on the quality of reaction, symptoms, and timing of the onset of the reaction. Results: Of 1253 calls to the CCC, 113 were identified as requiring consideration by a panel of three (American Board of Allergy and Immunology) ABAI-certified allergists for future dosing or formal in-person assessment. Of the 113 EHCPs, 94 (83.2%) were recommended to get their second dose. Eighty of 94 received their second planned dose without a severe or immediate reaction. Of the 14 of 113 identified as needing further evaluation, 6 were evaluated by a physician and subsequently received their second dose without a serious adverse reaction. Eight of 14 did not receive their second dose. Only 5 of the 113 EHCPs reported reactions (4.4%) were recommended to not take the second dose: 3 (2.6%) because of symptoms consistent with anaphylaxis, and 2 because of neurologic complications (seizure, stroke). Conclusion: The panel demonstrated that, by consideration of reaction history alone, the ECHPs could be appropriately triaged to receive scheduled second dosing of COVID-19 vaccines without delays for in-person evaluation and allergy testing.