It is also instructive to know that until recently, the CDC did not recommend wearing a face mask or covering of any kind, unless a person was known to be infected, that is, until recently. Non-infected people need not wear a mask. When a person has TB we have them wear a mask, not the entire community of non-infected. The recommendations by the CDC and the WHO are not based on any studies of this virus and have never been used to contain any other virus pandemic or epidemic in history.