Autoimmune reactionWhat makes people long-haulers? There are at least three possibilities. One leading theory is that the battle with the virus sets off an autoimmune reaction that persists long after the actual virus.
This may be what has happened to Clark. The theory is that “the immune system is cranked up" during the initial illness but once the virus is gone, it doesn’t come back down, says Avindra Nath, a researcher at the National Institute of Neurological Disorders and Stroke.Another possibility is that fighting Covid-19 leaves behind a detritus of viral particles that sets up a generalized cycle of inflammation long after the pathogen itself has departed.