More information has emerged about "COVID arm" — a delayed arm rash appearing after Moderna's COVID-19 vaccine is administered — including likelihood, duration and treatment.
A small study published in March found some recipients of Moderna's COVID-19 vaccine experienced delayed rashes. Another study, published May 12 in JAMA Dermatology and led by researchers from New Haven, Conn.-based Yale School of Medicine, provides more information about the condition.
Researchers examined 16 patients who experienced red and itchy blotches on their arms after receiving the COVID-19 vaccine. The patients, whose ages ranged from 25 to 89, were referred to Yale New Haven (Conn.) Hospital from Jan. 20 through Feb. 12, 2021.
The researchers emphasized the fact that such reactions are rare, citing the clinical trial that led to the vaccine's emergency approval, in which 312 such cases were reported out of more than 30,000 participants.
Seven report findings:
1. Of the 16 patients, 13 were women. Women are more vulnerable than men to "hypersensitivity" reactions to vaccines, and are also more likely to report such side effects to physicians, the researchers wrote.
2. None of the reactions arose at the time of vaccination. The skin reaction appeared anywhere from two to 12 days after the first Moderna shot, with a median latency to onset of seven days.
3. The arm reaction lasted for a median of five days, but could persist for up to 21 days.
4. Most people who had a skin reaction after the first shot also had a reaction after the second, typically around two days after the injection.
5. Treatments such as topical steroids, oral antihistamines and cool compresses can help.
6. No serious adverse events tied to this reaction were observed.
7. No such arm reactions were observed in individuals receiving Pfizer's vaccine. It's not known why Moderna vaccinations are tied to the side effect.