> I was pro-mask for a while before we had data Before COVID-19, we had extensive analysis of previous pandemics, with the consistent judgment that public mask

> I was pro-mask for a while before we had data Before COVID-19, we had extensive analysis of previous pandemics, with the consistent judgment that public mask-wearing had no noticeable effect. For example, the DoD commissioned a study of the 1918-1920 pandemic. (https://news.ycombinator.com/item?id=30179067 https://news.ycombinator.com/item?id=30179067)