Injection site reactions of redness and tenderness are not uncommon following COVID-19 vaccinations. These symptoms typically resolve over the following 4 to 5 days.
A more pronounced, delayed hypersensitivity skin reaction, consisting of a very large area of redness, itching, swelling, and soreness at the injection site, has been summarized in a 12-person case series. This reaction was noted in the phase 3 clinical trial of 30,000 participants who received the first dose of the mRNA-1273 (Moderna) vaccine. The delayed skin reaction had a median onset of 8 days following the initial dose (range, 4 to 11 days).
While the reaction is not serious, most of the patients were treated with ice and antihistamines. Some received corticosteroids (topical, oral, or both). Six of the 12 did not have a reaction to the second dose of the vaccine. Three people had reactions that were similar to those after the first dose; another 3 had second reactions that were less severe than those after the first dose. Similar reactions have been reported by individuals who received the Pfizer COVID-19 vaccine.
Neither local injection-site reactions or delayed hypersensitivity skin reactions are contraindications to a second vaccination. Let patients know it is not uncommon to develop redness, itching and swelling after getting the vaccine – in rare cases it may start 7 to 10 days later.
• Blumenthal K, et al. N Engl J Med 2021; letter to the editor, DOI: 10.1056/NEJMc2102131