I believe that when I was in rehab, I had covid. I definitely had an unidentifiable thing that wasn't the flu, but also wasn't pneumonia or anything else they could identify. They gave me two separate antibiotics for it and doubled down on asthma treatments. I also stopped eating because everything tasted like sand. I recovered. But it took over ten days, and then I was slow to regain stamina.

Obv can't prove it, but if I had to place bets ...