If NO symptoms, then NO need to wear mask - WHO twat from Mar 26, 2020·

World Health Organization Western Pacific @WHOWPRO

If you do not have any respiratory symptoms, such as fever, cough, or runny nose, you do not need to wear a medical mask. When used alone, masks can give you a false feeling of protection and can even be a source of infection when not used correctly.

2-minute clip

https://twitter.com/WHOWPRO/status/1243171683067777024