Or maybe it was that earlier film with Charlton Heston. The Ten Commandments, was it? 1956?
Just for once, let's be told to do something that we're not told a week later is pointless. A scientish came on the news this morning - I like "scientish"; mistype, but I'll leave it - to declare that mask-wearing may be ineffective against covid-19.
"May" is another "could" word. Covid-19 "may" get through masks. The virus "could" still get to you through your mask.