The term "long Covid" is used to describe patients whose medical problems continue long after the coronavirus has left their system. Immunologists Akiko Iwasaki, PhD, and Aaron Ring, MD, PhD, have identified autoantibodies in patients who have had COVID-19. Autoantibodies are antibodies (proteins produced in response to a pathogen) that mistakenly target and react with a person's own tissues or organs. The Yale team has identified these autoantibodies in other systems of the body, which may help to explain why some patients develop specific conditions from the virus, including post-COVID syndrome. More research is needed to determine if long Covid patients have these autoantibodies, which may be a potential therapeutic target for COVID-19.