"Ain't that the truth!" ... Other old saying.What's that old saying? "Don't let perfect be the enemy of good" ?
Obviously, having military NBC (Nuclear-Biological-Chemical) level precautions would be "state of the science" but COVID isn't like a nerve agent where a single droplet could kill you.
It's a virus, so there are a lot of other factors to transmissability that I could go into at length, but the TL;DR is "wearing a mask works!"