[petercooper]

I personally believe that any sort of cover or mask is likely to have an effect even if not 100%. However..:

This is a bizarre claim that can be countered against the reality that every front-line worker is equipped with a mask.

This is not necessarily to protect the front-line workers. Since the incubation period is so long, it makes sense for front-line workers to wear masks to prevent them infecting other people even if it has zero effect in preventing them being infected in the first place.

[Rastonbury]

Agreed. Even before Covid it was standard for healthcare workers to wear masks. They constantly work with patients with compromised immune systems and the like. They could be be asymptomatic and wouldn't risk passing it to someone weaker