That is the thing. They don't know at this point. Guess on your time not mine. Wearing a mask "may" help slow the spread by 10% -70% Not stop it. Hospitals are not topped again now. This is junk science and a joke. And that is the opinion of some trained professionals and scientist so.... If you know anything about science, ANYTHING !, nothing is give credit or proven for years until its been vetted.Here we go with the cherry picking again. A couple scientists note cooling temperatures over a period of years, and decide to publish a paper with their findings and opinions as to what might be causing it. 50 years later it is used as a touchstone for anti science far right agenda, and all of the great things, far too numerous to list, that science has done and discovered up to and since is cast aside because an example can be found of an incorrect assumption. Kind of a ridiculous argument to stake a flag in if you even bother to think about it for more than the briefest of moments.... Should I throw all scientific evidence, research, discovery, out of the window because Phillip Morris carted out a few scientists that stated smoking isn't bad for you? I think not.
Here's the thing, there's a whole lot we don't know. Scientists regularly butt heads with one another when trying to figure things out and when a large group of them gather in conference I can assure you it can get just as loud, argumentative and derogatory as anything we see daily in politics. Observation, measure, research, experiment, determining fact, takes time and often requires trial and error to lead to success. Let's not fault the millions of brilliant minds that have greatly contributed to the advancement of the human race because we can sometimes catch them screwing up as that is very much a part of the learning process.
mandate? Pfftt, i'm a Free Man and i can and will make my own decisions. And respect others in theirs. Now i use a mask myself for many reasons. All of those are my reasons and not because of a mandate or what some scientist believes.