A rash that appears on the arms of some people who receive the Moderna COVID-19 vaccine is harmless, a new study suggests.
Researchers looked at data from 16 Americans who developed so-called ‘Covid arm,’ in which people experience itchy and swollen skin, sometimes accompanied by red lumps or hives.
They found that the reaction is simply a response from the immune system to the shot that fades within a week.
The team, from Yale University School of Medicine, in New Haven, Connecticut, says that no serious events were reported in their patients and that there is no reason why those who get the rash after the first shot shouldn’t receive the second dose.
A new study looked at 16 patients who experienced a rare side effect, dubbed ‘Covid arm’ that appears as a red and swollen splotch after receiving the Moderna vaccine (left and right)
Almost all patients were treated with topical steroids, oral antihistamines, and cool compresses and one was given an antibiotic, and all rashes disappeared within a week
The official term used by dermatologists and allergists to describe the side effect is ‘delayed cutaneous hypersensitivity.’
Cutaneous means affecting the skin, hypersensitivity mean an unwanted reaction produced by the immune system and delayed because it typically occurs days after the shot is given.
The rash is typically red and swollen, and sometime painful to the touch, and always appears on the arm in which the vaccine was administered.
Such reactions have also been found in people who’ve received tetanus vaccines, the chickenpox vaccine and the MMR (measles, mumps, rubella) vaccine.
But Covid arm has only occurred in people who received Moderna’s coronavirus vaccine, not Pfizer’s, and has been reported in their clinical trials.
In a previous interview, Dr Peter Chin-Hong, a professor of medicine and infectious disease specialist at the University of California, San Francisco, told DailyMail.com that he likens the side effect to the immune system being in a military-style boot camp.
‘The boot camp is a gradual process. In the beginning, the antibodies or the fighting soldier cells that you develop aren’t fully trained,’ he said.
‘Then they’re being trained and in that process of training, they get very excited or anxious or angry, because they’re working hard and they become very good over time.’
That ‘angry’ feeling from the solider can manifest as Covid arm.
For the study, published in JAMA Dermatology, the team looked at 16 patients referred to Yale New Haven Hospital’s Dermatology Services between January 20 and February 12, 2021.
All received the Moderna coronavirus vaccine and just one had a history of reactions to other vaccines.
Four had seasonal and/or food allergies and four were allergic to certain antibiotics including Cefalexin and TMP-SMX (Trimethoprim / Sulfamethoxazole).
The remaining eight had no allergies of any kind.
Of the 16 patients, 15 developed ‘Covid arm’ after the first dose and one only after the second dose.
Reactions typically occurred about seven days after receiving the dose with most appearing hardened and swollen with fluid. Less commonly, some of the rashes were ring-shaped.
Patients were treated with topical steroids, oral antihistamines and cool compresses, and the rash disappeared after about five days.
Twelve patients also developed reactions after the second dose, 11 of whom also had reactions the first time.
The reactions not only appeared sooner, about two days after being given the dose, but also disappeared more quickly, after about three days.
None of the patients needed to be hospitalized and only one required an antibiotic for cellulitis, a potentially serious bacterial skin infection.
‘Findings of this case series study indicate that the localized injection-site reactions to the Moderna COVID-19 vaccine are a delayed hypersensitivity reaction,’ the authors wrote.
‘These reactions may occur sooner after the second dose, but they are self-limited and not associated with serious vaccine adverse effects.’
Vaccinated people have been posting on Reddit whether or not they have had side effects have receiving coronavirus vaccines
Meanwhile, some vaccine recipients have taken to a group on the social media site Reddit to talk about their side effects, or lack thereof, after getting the jab.
Thousands of posts on r/CovidVaccinated detail symptoms after receiving the first or second dose of the coronavirus vaccine.
‘I had my second dose of Moderna on Monday. Yesterday (the next day) was awful! I knew it might be, but I was still pretty surprised by how bad it was,’ wrote one user.
‘I had a fever and intense chills from 9 am til 4 pm…It was pretty brutal. I can’t imagine what it must be like for folks who got covid so I’m glad to be vaccinated!’
Another person detailed their experience after the first Pfizer dose: ‘Had my first dose 4/29. Immediate headache, fatigue, brain fog. One week of bad headaches, constant fatigue, constant napping.’
However, others said their appointments were overall pleasant.
‘For the first dose my arm was just a little sore and that was the only thing I felt,’ someone wrote after getting the Pfizer shot.
‘For the second dose I was more sore for the rest of the day, took a nap because I was feeling pretty tired and waking up the next day I felt totally fine!’
Another user posted about getting the Moderna jab: ‘My experience with this vaccination was that it was harmless as a flu shot to me and also had the benefit of lowering my stress about the whole situation. ‘