Comment by renaudg

> they did a big review of mask studies and found there was no reliable evidence that masks worked against COVID.

No, that was a misinterpretation of the review in the Covid-skeptic sphere. Cochrane have had to issue a statement to clarify : https://www.cochrane.org/news/statement-physical-interventio...

tl;dr : half of the people given masks in these studies didn't wear them consistently or at all, dragging efficacy results down.