Many experiencing long-term brain fog after COVID-19 diagnosis Some people are experiencing long-term brain fog after a coronavirus diagnosis. and last updated 2021-05-24 08:47:11-04 That fuzzy, confusing, light-headed feeling that some people who have had COVID just can't seem to shake -- also known as "brain fog." "Brain fog is not a medical term, but we've all felt it, right?" says ABC15 Health Insider Dr. Janice Johnston with Redirect Health. "We've taken an antihistamine or maybe something that's a sedating kind of drug. Or maybe feeling a little under the weather or jet-lagged, or that kind of thing?" Dr. Johnston explains that feeling typically goes away once you start feeling better, but for some, the brain fog has a hard time clearing up. Dr. Johnston tells us there are a number of factors.