1. there is evidence that masks can prevent spread of droplets from infected person to another person and to the environment
3. there is no evidence at the moment in community setting that mask, "including universal community masking", can prevent healthy person being infected.
On the plus side, WHO says it may reduce risk of pre-symptomatic patients transmitting virus and may reduce the awkwardness/stigma of wearing mask for symptomatic people.
- a false sense of security that could lead to more carelessness
- danger of mask shortage for health care workers
- less ressources for more important measures
- breathing difficulties
- self-contamination by touching and reusing contaminated mask