"COVID arm" is a term experts are using to describe a delayed itchy rash or dull pain following a COVID-19 vaccine. The condition is currently most strongly linked to the Moderna mRNA vaccines but can occur after others. Doctors say that the effect is harmless and people should not let it deter them from getting their second dose of the vaccine. The symptoms can appear after a week since someone received their first dose of the COVID-19 vaccine. Symptoms include redness, swelling, tenderness or a skin rash eight or more days after receiving the injection. Researchers say that the reaction should fade by itself after four or five days. Researchers say that less than 1% of those involved in early trials of the Moderna vaccine developed a raised or itchy rash.