[peytn]

We did not forget. We did experiments with gauze face masks. Here’s one from 1920:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1362677/

I’m not aware of any recommendations to wear gauze face masks.

[squarefoot]

I was referring in general to wearing masks, not strictly gauze ones. They probably realized afterwards that gauze ones weren't the most effective, but some of todays people jumped straight to refusing masks.