They go on to talk about the possibility of tiny blood clots that even if and when they resolve could leave lasting tissue damage.
Doctors aren’t quite sure what causes chronic fatigue, but the syndrome can be triggered by infectious diseases like Lyme disease or Epstein-Barr virus. Some patients can be sick for several years, while others never fully regain their health. Some may never be able to return to work at all.
Based on what doctors know so far, blood clots may be one reason some COVID-19 patients feel fatigued.
“If people have a bunch of small clots in their lungs, that can continue to cause fatigue for a long period of time — even after the clots are gone — if there’s damage to the blood vessels,” Favini said.
An aggressive immune response to the virus could also trigger inflammation in the body that damages healthy tissue.
“We think that people’s baseline immune system predicts who will get chronic fatigue,” Dr. Frances Williams, a rheumatologist and professor of genomic epidemiology at King’s College London, told Business Insider. Her research team is currently examining the link between the coronavirus and chronic fatigue syndrome among adult twins.