There’s not a mask on the market that will PREVENT the spread of Covid.
But guess what? Even a cheap paper mask will help slow down the risk.
By how much? Where is the risk analysis? Are they doing more harm than good for people’s physical and mental health, and social and economical well-being?
Reducing the speed limit to 10 mph would prevent a majority of the car deaths in the world, but we don’t do that for good reasons.