There is a reason all these guys give you crap advise. Because you want guarantees for everything , otherwise some pathetic lawyer will team up with you to sue whoever gives you honest advise. This is the reason that little tiny lingerie comes with at least 5 huge tags stitched to it , one from state of california, some from 4 other crap agencies, all to 'protect you'. No one wants to speak the truth, beccause everyone fears the invisible craplawyer present in the room. The truth is that if everyone wears an appropriate mask, it would indeed 'harden' the environment against the virus, make life less fun for the virus. And you dont need to be Einstein to figure it out. Just use common sense. Oh i am sure hte FDA will say 'there is no evidence in any of the published double blind studies that shows that common sense is of use'. You bet! So now you have the CDC that says 'wear kerchiefs or anything you can get' and the FDA which is blocking imports of life saving masks from China and the surgeon general says 'people, stop buying masks' (wow, what a professional sounding statement) .. i am sure his esteemed highness has nothing against you buying caskets.. So shut up , use common sense and protect yourself, and stop deluding yourself that the government exists to 'take care' of you..