Face masks are a powerful tool of prevention: One study has shown that if everyone wears masks that are only 75% effective, then the number of people infected by each coronavirus carrier will shrink fourfold

Face masks are a powerful tool of prevention: One study has shown that if everyone wears masks that are only 75% effective, then the number of people infected by each coronavirus carrier will shrink fourfold https://t.co/isp2yGUYFS

— Bloomberg Opinion (@bopinion) September 27, 2020