Delayed Local Hypersensitivity Reaction to ModernaCOVID-19 Vaccine
The clinical and histopathological findings of this case series study indicate that local injection site reactions to ModernaCOVID-19 vaccine are delayed hypersensitivity reactions. These reactions can occur soon after the second dose, but are self-limiting and are not associated with serious adverse vaccine reactions. In contrast to immediate hypersensitivity reactions (e.g., anaphylaxis, urticaria), these delayed reactions (referred to as the "COVID arm") are not contraindications to subsequent vaccination.
Johnston MS, Galan A, Watsky KL, Little AJ. Delayed local hypersensitivity reaction to Moderna COVID-19 vaccine: a case series. Jama Dermatol. Published online May 12, 2021. doi: 10.1001 /jamadermatol.2021.1214
Commentary.
This study was conducted on 16 patients to find the characteristics.
Patient characteristics ranged from 25 to 89 years of age, 13 were female, 14 patients were Caucasian, and 2 were Asian. all 16 participants had received the ModernaCOVID-19 vaccine, and one of them had previously been reported to have had a mild local vaccine reaction. Most of these patients were health care workers, and of the 16 patients, 15 had local skin reactions after the first dose. Pruritic, variously painful erythematous reactions near the injection site after the first dose were observed to occur 2-12 days after the vaccine administration.
In addition, 16 patients were given a second dose, and 12 patients were found to have injection site reactions that occurred 0-5 days after administration. One of these 12 patients had no reaction after the first dose. Of the 15 patients who had a response after the first dose, 11 had a response after the second dose, and the onset of the second response was reported to be earlier than the first.
