Why did the FAA change ECG requirements, and what is the change about?

I flew with a pilot some time in 2022 who told me that when the original vaccine mandate came out he was fully willing to resign and abandon his career as an airline pilot before he would accept that poison in his system. It was evident that he was not blustering; he meant it. I replied that I’d been poisoned 4 times now with no apparent ill effects, twice before the mandatory idea ever reared its head.

The next hour or so in flight was … quiet. All business. Which is fine with me; we’re not all instant pals once locked into our shared broom closet for a few days. I’d rather have somebody with silly ideas be quiet than keep spouting. I imagine he felt the same way. I did not ask.