Covid 19 requires moisture to spread to other people. So, the people who need to wear a mask are those who are sick and can spread the virus by coughing, sneezing, or loud talking. And, people who are ill should be at home under self-quarantining. So, who needs a face mask? Dr. Len and Francesco discuss this and provide sensible guidelines for who needs a face mask to prevent Covid 19 infections. They also go over the reasons why face masks have a negative effect that can worsen Covid 19 infections.