Delayed Injection Site Reaction to Moderna Vaccine Common in Women

Delayed injection site reactions to the mRNA-1273 SARS-CoV-2 vaccine occur commonly in women and do not lead to serious adverse events, according to a study published in Clinical Infectious Diseases.

Researchers performed an observational cohort study of hospital workers who received the Moderna mRNA vaccination between December 14, 2020, and January 8, 2021, and reported onset of an injection site reaction 48 hours or more after administration of their first or second dose to an employee hotline.

Of the employees, 13 reported a pruritic rash at the injection site appearing 3 to 9 days after receiving their initial dose. One reported a delayed reaction after the second dose. None of the employees reported serious adverse events. The cases represented 1.1% of the female employees who received their first dose.

“These results suggest that delayed-onset, injection-site pruritic rashes after mRNA-1273 SARS-CoV2 vaccine administration, lasting up to a week, occur commonly in females, do not lead to serious sequela, and should not deter receipt of the second vaccine dose,” concluded the study authors.

Reference
Jacobson MA, Zakaria A, Maung Z, et al. Incidence and characteristics of delayed injection site reaction to the mRNA-1273 SARS-CoV2 vaccine (Moderna) in a cohort of hospital employees. Clin Infect Dis. Published June 4, 2021. doi:10.1093/cid/ciab518