It is one of many mysteries about long Covid: Who is more prone to developing it? Are some people more likely than others to experience physical, neurological or cognitive symptoms that can emerge, or linger for, months after their coronavirus infections have cleared?
Now, a team of researchers who followed more than 200 patients for two to three months after their Covid diagnoses report that they have identified biological factors that might help predict if a person will develop long Covid.
One of the four factors researchers identified is the level of coronavirus RNA in the blood early in the infection, an indicator of viral load. Another is the presence of certain autoantibodies — antibodies that mistakenly attack tissues in the body as they do in conditions like lupus and rheumatoid arthritis. A third factor is the reactivation of Epstein-Barr virus, a virus that infects most people, often when they are young, and then usually becomes dormant.
The final factor is having Type 2 diabetes, although the researchers and other experts said that in studies involving larger numbers of patients, it might turn out that diabetes is only one of several medical conditions that increase the risk of long Covid.
