How effective are public health mask-wearing measures?

Australian researchers have found mask-wearing reduces halves the incidence of COVID-19

Mask-wearing is the most effective public health behaviour in curbing the spread of COVID-19, reducing infections by more than half, an Australian-led review shows.

Donning a mask, hand-washing and maintaining physical distance are all linked with reductions in the incidence of the virus according to the researchers who reviewed 72 studies.