I've posted links before, and I'll try to find them when I'm not on my phone. But you're right. It was an open question, but the general opinion before 2020 wa

I've posted links before, and I'll try to find them when I'm not on my phone. But you're right. It was an open question, but the general opinion before 2020 was that masks would not be particularly useful. Sketchy results started appearing in March with better days in April and May. Several experts said, "we were wrong." Medical grade masks are very useful. Others are less so. But they primarily prevent you from giving the virus to others.