>>chvid+Ga
Mask do not protect the person wearing the mask (unless you talk about the kind of masks used as PPE for medical professionals).
They do protect other people from the person wearing the mask spreading the virus. The consequence is that for masks to work at scale a large number of people need to wear them.
>>DasIch+6d
CDC says that to the public yet in their information to doctors and nurses says a bandanna or scarf can substitute for an N95 mask but with less effectiveness.