An angry red rash being called “COVID arm” is a harmless but annoying response in some people who get the Moderna vaccine. Aside from sometimes being itchy, it doesn’t appear to be dangerous and people who get it should not hesitate to get their second dose of the vaccine. “We want to reassure people that this is a known phenomenon, having a big red splotch on your arm for a couple of days may not be fun but the reality is there’s no need to panic and no reason not to get your second shot” said Dr. Esther Freeman, director of global health dermatology at Massachusetts General Hospital.

The rash is red, sometimes itchy and painful to the touch, and can be as much as five or six inches across. It always occurs on the arm where the shot was given. The specific reaction has occurred only in people who’ve gotten the Moderna vaccine, not the Pfizer vaccine. What is unusual is that the rash typically shows up five to nine days after the first immunization, on average, a week later. That makes it different from most vaccine side effects, which typically occur within a day or two.

The most important message, doctors say, is the rash is a harmless, short-term reaction. “We don’t want people to panic” Freeman said “and we don’t want people to think they can’t get their second dose just because they have this delayed reaction. Stay the course, stay well, mask up, get vaccinated and stay tuned!