I think what happened is that SARS and MERS built up the immune systems of folks. And since Covid is so similar, it was easy for the already-present-immune-antibodies to convert slightly to protect from Covid. Possibly the antibodies for SARS or MERS work directly on Covid without any conversion at all.



EDIT: I think I'll drink the last of the OJ, and pop a gram of vitamin C at the same time.

EDIT 2: Btw, it's Walmart/Chinese vitamin C, so who knows what might be in it?