COVID-19 Vaccine: Delayed Large Local Reactions Possible

By Kelly Young

Edited by Susan Sadoughi, MD

A series of delayed cutaneous reactions in 12 patients after receiving the Moderna mRNA vaccine are described in the New England Journal of Medicine.

Reactions appeared near the injection site at a median of 8 days after their first vaccine dose; five patients had plaques at least 10 cm in diameter. Overall, symptoms resolved after a median of 6 days. Most patients received symptomatic treatment with ice and antihistamines, while some received glucocorticoids and one received antibiotics.

All patients were encouraged to receive their second dose as these reactions are not contraindications. Half the patients had recurrent reactions after their second dose, with symptom onset a median of 2 days' postvaccination.

The authors conclude: "We hope this letter encourages additional reporting and communication regarding the epidemiologic characteristics, causes, and implications of these delayed cutaneous reactions, since this information might allay the concerns of patients, encourage completion of vaccination, and minimize the unnecessary use of antibiotic agents."