Delayed cutaneous reaction to COVID-19 vaccine should not preclude further vaccinations

Delayed localized cutaneous reactions to the Moderna COVID-19 vaccine are not a contraindication to receiving subsequent vaccinations, according to a case series study.

“In the U.S., the Pfizer-BioNTech and Moderna mRNA COVID-19 vaccines were granted emergency use authorization in December 2020 with more than 48 million doses administered nationwide to date,” Margaret S. Johnston, MD, of the department of dermatology at Yale University School of Medicine, and colleagues wrote in a brief report. “As vaccine administration increases, recognition and understanding of these novel vaccines’ adverse effects are essential.”

Sixteen patients who received the Moderna vaccine and had a delayed cutaneous reaction were included in the case series; 15 had reactions after the first dose, and one had a reaction only after the second dose.

Eleven of the 15 patients who had a reaction after the first dose also experienced a reaction to the second dose, with reactions being clinically similar.

The delayed reaction, called “COVID arm,” occurred 2 to 12 days after the vaccination and consisted of pruritic and painful erythematous skin near the injection site lasting a median of 5 days.

Skin biopsy results showed a mild predominately perivascular mixed infiltrate with lymphocytes and eosinophils. This is consistent with a dermal hypersensitivity reaction.

“These cutaneous reactions occur near the injection site and are benign and self-limited,” the authors wrote. “In contrast to immediate hypersensitivity reactions (eg, anaphylaxis and urticaria) that present within 4 hours of vaccine administration, these delayed localized hypersensitivity reactions are not a contraindication to subsequent vaccination.”