Fatigue, sometimes profound, is one of the most common and debilitating features of long COVID. Its presence predicts far worse clinical outcomes, as evidenced by deaths and hospitalizations, than patients without fatigue.
Chronic fatigue syndrome
Some medical conditions are especially frustrating to physicians. That's because they lack not only effective treatments but even a reliable means of diagnosis. One of the most common is variously known as myalgic encephalomyelitis, or chronic fatigue syndrome (ME/CFS). Dr. Henry Miller will explain it to you (if you're not too tired to read it).