I understood it as a measure to keep the healthy from getting it (N95 style) rather than surgical style masks for preventing those already ill from spreading. I’m not a medical professional. So I have no idea about efficacy. My question to the smart guys is why not use masks even if it’s only a small reduction? I’m locked in my house until June by my governor in order to protect the most vulnerable. Wearing masks doesn't seem more extreme than that. If supply is the issue, why not go the homemade mask route such as proposed by Lex Fridman and others?
Another question to the medical types. I’ve read anecdotal evidence several places that the amount of virus a person receives in the initial exposure plays a role in severity of the illness. Some have even suggested that heavy repeated exposure such as medical professionals are subjected to, seem to cause severe illness beyond the age and underlying conditions. Is that true? If so, wouldn’t a mask greatly reduce the initial dose?