Don't laugh .... my wife has pulmonary fibrosis ... it's basically a mysterious inflammation of the lungs with your immune system running haywire. No one knows what causes it or what triggered it ... all we know is that it is happening. They suspect it was originally a virus of some kind (this all started about three / four years before the pandemic). There is no cure, there is no remedy, there is no healing, there is no recovery. It only grows worse with time, spreads through the lungs and drowns you to death as you run out of healthy lung to breathe.
Take care of your lungs everyone.