Omalizumab prevents anaphylactoid reactions to mRNA COVID‐19 vaccine

Background Cutaneous reactions after mRNA-based COVID-19 vaccines have been reported but are not well characterized. Objective To evaluate morphology and timing of cutaneous reactions after mRNA COVID-19 vaccines. Methods A provider-facing registry-based study collected cases of cutaneous manifestations after COVID-19 vaccination. Results From December 2020-February 2021, we recorded 414 cutaneous reactions to mRNA COVID-19 vaccines from Moderna (83%) and Pfizer (17%). Delayed large local reactions were most common, followed by local injection site reactions, urticarial eruptions, and morbilliform eruptions. Forty-three percent of patients with first dose reactions experienced second dose recurrence. Limitations Registry analysis does not measure incidence. Morphologic misclassification is possible. Conclusion We report a spectrum of cutaneous reactions after COVID-19 mRNA vaccines. Most patients with first dose reactions did not develop a second dose reaction, and no patients in the registry developed serious adverse events after the first or second dose. These data provide reassurance to patients and providers.

Vaccines against COVID-19 (and its emerging variants) are an essential global intervention to control the current pandemic situation. Vaccines often cause adverse events; however, the vast majority of adverse events following immunization (AEFI) are a consequence of the vaccine stimulating a protective immune response, and not allergic in etiology. Anaphylaxis as an AEFI is uncommon, occurring at a rate of less than 1 per million doses for most vaccines. However, within the first days of initiating mass vaccination with the Pfizer-BioNTech COVID-19 vaccine BNT162b2, there were reports of anaphylaxis from the UK and USA. More recent data implies an incidence of anaphylaxis closer to 1:125,000 doses with respect to the Pfizer-BioNTech vaccine. In this position paper, we discuss the background to reactions to the current COVID-19 vaccines and relevant steps to mitigate against the risk of anaphylaxis as an AEFI. We propose a global surveillance strategy led by allergists in order to understand the potential risk and generate data to inform evidence-based guidance, and thus provide reassurance to public health bodies and members of the public.