Some people have delayed reactions to their first dose of Covid vaccine, with their arms red, sore, itchy and swollen a week or so after the shot.
Although unpleasant, it seems to be harmless. But the foul skin condition can be mistaken for an infection, according to a letter published in The New England Journal of Medicine on Wednesday. The doctors said they wanted to share information about the cases to prevent the unnecessary use of antibiotics and to alleviate the concerns of patients and reassure them that they could safely get their second vaccination.
“We changed our patient distribution as soon as we started seeing it,” said Dr. Kimberly G. Blumenthal, an author of the letter and an allergist at Massachusetts General Hospital, said in an interview. ‘We said it’s normal to get redness, itching and swelling when you get the vaccine. We changed the wording to say it can also start seven to ten days after you get the vaccine. ”
The letter describes the experiences of 12 people who delayed a major local reaction, which began four to 11 days after the first ingestion of the Moderna vaccine, within a median of eight days. The report is not a controlled study, but rather a series of cases that came to doctors’ attention because the vaccine recipients were worried and wanted to know if they should get the second chance.
Most were vaccinated at Massachusetts General Hospital, where both the Moderna and Pfizer BioNTech vaccines were administered. But the delayed reactions only took place in people who received the Moderna shot, dr. Blumenthal said, adding: “I do not understand why.”
Moderna reported delayed skin reactions in its large clinical trial in 0.8 percent of recipients after the first dose and 0.2 percent after the second dose.
According to the letter from dr. Blumenthal and ten other physicians reported all 12 people typical symptoms such as a sore arm that often occurs shortly after vaccination, and the initial symptoms disappeared.
Then a delayed response struck. In five people, large, raised skin lesions emerged that were 10 or more centimeters in diameter near the injection site. Two had rashes elsewhere, one near the elbow and one on the palm of the hand. Some had systemic symptoms at the same time, such as fatigue and muscle aches.
Most treat the skin symptoms with ice and antihistamines. Some needed steroids, in cream or pill form, and one was prescribed an antibiotic by a doctor who mistakenly considered the problem to be an infection.
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The symptoms lasted a median of six days, ranging from two to 11 days. All the patients received the second shot. Half did not have a delayed reaction again, but three developed the same symptoms again and three had milder reactions than after the first shot.
Dr Blumenthal said there were many unanswered questions about the reactions. Ten of the 12 patients were women, but it is not clear whether women are more prone to the problem and whether the imbalance occurred because more of the vaccinated health workers were female.
Some have allergies to drugs, wasps or food, but others do not.
A skin biopsy in one patient indicated that the condition was a drug reaction. But what exactly the patient’s immune system responds to is not known.
“I hope the businesses will find out,” he said. Blumenthal said.
She is aware of about thirty cases, particularly among women and all recipients of the Moderna vaccine so far, she said. The hospital has set up a registry to track it down.