Some people get Moderna Inc.’s vaccine experience delayed rashes that can be four inches wide or more and take about six days to resolve, according to a report in the New England Journal of Medicine.
Researchers reported details on 12 cases of reactions that appeared eight or more days after people received their first dose. They were usually treated with ice and antihistamines, although some patients required steroid treatments. About half also had skin reactions after the second dose, although these were less severe.
While there have been previous reports of the reactions occurring mainly with the Moderna shot, their appearance can be surprising. The details should help educate doctors and reassure people who develop them, said Kimberly Blumenthal, the paper’s lead author and co-director of the clinical epidemiology program at Massachusetts General Hospital in Boston.
Delayed reactions after vaccination in a dozen patients.
he New England Journal of Medicine © 2021
“Our goal was to show how dramatic they can be, when no one was worse with dose 2,” she said in an email response to questions. “So many of the patients I took care of with this were concerned about them. Is this an infection? (No!) Does this mean that I cannot receive dose 2? (No!) Will it happen with dose 2? (Not necessary!).”
“This is annoying, but it is not dangerous,” she said in an interview.
Covid arm
Evidence of the responses appeared in previous studies. Moderna’s latest trial of the vaccine noted delayed first injection site reactions in approximately 0.8% of the 30,420 participants and 0.2% with their second dose. They usually disappear within about five days.
Reports of vaccine rashes, colloquially referred to as “ Covid arm, ” appeared in a Facebook group of pharmacists earlier this year. The pharmacists shared their experiences in the “Pharmacy Staff for Covid-19 Support” group and posted pictures of large red circles on their arms. People asked what members of the 44,000 community knew about the phenomenon and whether others saw similar effects.
The delayed responses to the Moderna vaccine are different from the immediate injection site reactions that usually occur with both the Pfizer Inc. and Moderna messenger RNA vaccines, Blumenthal said.
“This is a Moderna-specific reaction that pops up after the first week and can last for several days,” she said. “I haven’t been told about Pfizer,” she said.
Exactly what causes them is unknown, but it could be some type of immune response to inactive components of the vaccine, she said.
While most delayed reactions developed on the shoulder and upper arm near the injection site, others appeared on the elbow and the fingers and palm, according to the study. In some cases, the tissue under the skin’s surface hardened and lost its smooth appearance in response to the inflammation.
– With the assistance of Angelica LaVito
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