““I looked at the number of patients that were in the database and it was, I think, 1,800 patients,” he told me. “I freaked out a little bit. Oh my God, there’s so many patients telling us that they still have symptoms.” A realization dawned on him: America was not simply struggling to contain a once-in-a-century pandemic, caused by a virus far more dangerous than seasonal influenza. Many patients were, for unknown reasons, not recovering.”

https://www.theatlantic.com/magazine/archive/2021/04/unlocking-the-mysteries-of-long-covid/618076/