Bruce Wheeler was diagnosed with COVID-19 last spring, but never fully recovered, suffering a variety of symptoms of what has become known as "long COVID." He's not alone — according to a UC Davis overview of a handful of recent studies, more than one in four COVID-19 patients develop symptoms lasting for months, even if they had mild cases. Bruce and Dr. Brian Block, who has helped treat him and who is one of the founding clinicians at UCSF’s COVID recovery clinic, talk about the condition and what's still unknown about it.