WHO - When and how to wear medical masks to protect against the new coronavirus? - March 26, 2020
"If you do not have any repiratory symptoms, such as fever, cough or runny nose, you do not need to wear a medical mask like this one."
"Masks alone can give you a false feeling of protection, and can even be a source of infection when not used correctly."
Dr. April Baller
WHO - Health Emergencies Programme