Blood Markers of Long COVID Identified

Long COVID affects 1 in 13 U.S. adults, or 7.5%, according to survey by the Centers for Disease Control and Prevention. A study recently publsihed in the journal Nature found differences in the blood samples of 273 individuals with and without long COVID. The findings are being hailed as the first step in the development of a test to diagnose the illness that has left millions with ongoing fatigue, cognitive issues, heart rate and blood pressure variation, and other debilitating symptoms.

The activity of immune system cells called T cells and B cells, which help fight off germs, was irregular in long COVID patients. The long COVID patients also had significantly lower levels of cortisol, a hormone that makes people feel alert and awake. Future studies are needed to understand cortisol’s role in long COVID.

The study also found that dormant viruses, such as Epstein-Barr that causes mononucleosis, are activated in long COVID patients. Future research is need to detimine whether these viruses are causing symptoms or identifying a problem within the immune system.  

The scientists did not find significant evidence that long COVID is the result of an autoimmune disorder, when the body's immune system attacks and destroys healthy body tissue by mistake.