Long Covid is a chronic illness resulting from a Covid-19 infection. It goes by many names, including long-haul Covid, post-Covid or post-acute Covid syndrome.
Not much is yet known about the illness. Its symptoms number in the hundreds and can be debilitating. They can also be challenging to diagnose — for doctors even willing to do so.
Long Covid has affected as many as 23 million Americans. It may cost the U.S. economy $3.7 trillion, roughly that of the Great Recession, according to one estimate.