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New Vaccine Side Effect Discovered, Doctors Say

Some people are experiencing this delayed reaction.
FACT CHECKED BY Alek Korab
A man experiencing discomfort in his upper arm

Some people who've gotten the COVID-19 vaccine are experiencing a delayed reaction to the shot, developing redness, itching or swelling in their injection arm a week or more after they've been vaccinated. Experts don't know why this happens, but the reactions seem to be harmless, reports the New York Times. This week, a group of doctors published a letter published in the New England Journal of Medicine to let patients know they're not experiencing an infection and they're safe to get their second dose of the vaccine.  Read on to discover more—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had Coronavirus.

It's "Normal to Get Redness, Itching and Swelling," Say Some Doctors

"We modified our patient handout once we started seeing this," Dr. Kimberly G. Blumenthal, an author of the letter and an allergist at Massachusetts General Hospital, told the Times. "We had said it was normal to get redness, itching and swelling when you get the vaccine. We changed the wording to say it can also start seven to 10 days after you get the vaccine."

The letter discussed the cases of 12 patients who developed a reaction in their arm four to 11 days after receiving the Moderna vaccine. (The median was eight days.) Five people developed large, raised skin rashes measuring more than 10 centimeters near the injection site. One person developed a rash on their palm, another on their elbow. The symptoms lasted a median of six days.  

RELATED: If You Feel This You May Have Already Had COVID Says Dr. Fauci

How to Deal With "COVID Arm"

On its website, the CDC refers to the phenomenon as "COVID arm." "CDC has learned of reports that some people have experienced a red, itchy, swollen, or painful rash where they got the shot," the agency says. "These rashes can start a few days to more than a week after the first shot and are sometimes quite large."

The agency recommends taking an antihistamine or over-the-counter pain reliever for any itching or pain, adding that COVID arm shouldn't prevent you from getting your second shot if your vaccine is a two-shot regimen. "Tell your vaccination provider that you experienced a rash or 'COVID arm' after the first shot," the agency says. "Your vaccination provider may recommend that you get the second shot in the opposite arm."

As of March 4, about 27.7 million people in the U.S. have been fully vaccinated against COVID.

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How to survive this pandemic

As for yourself, do everything you can to prevent getting—and spreading—COVID-19 in the first place: Wear a face mask, get tested if you think you have coronavirus, avoid crowds (and bars, and house parties), practice social distancing, only run essential errands, wash your hands regularly, disinfect frequently touched surfaces, and to get through this pandemic at your healthiest, don't miss these 35 Places You're Most Likely to Catch COVID.

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