Scientists have taken the first step toward a test for long COVID.
A study published today in the journal Nature says that there are clear differences in the blood of people with the ailment. The activity of immune cells T-cells and B-cells is "irregular." But more importantly, people with long COVID tend to have lower levels of cortisol.
Researchers believe that the cortisol deficiency could explain some of the symptoms of long COVID, such as fatigue. The hormone helps us feel alert and awake.
Now that researchers have identified those blood differences, a test for them could be developed. However, the study did not find underlying causes for these differences, so an effective treatment for long COVID could still be a long way off. (NBC News)