There are many variables, and I’m not sure about it myself. From what I’ve seen, though, it just seems common sense that masks would help at least a little.
I haven’t found the story, but wasn’t there a report within the last few weeks about a long air flight in which everyone wore masks, and someone was discovered to have had the virus immediately afterward (and apparently had been infectious during the flight)? The authorities then traced the other passengers on the flight and didn’t find any that had caught the virus.
If that’s true, that would seem very significant. I wish I had the source. I tried searching the net for plane covid masks, but just see general stories about masks and planes. If anyone else has the link, please post it.
(I don’t guarantee the accuracy. Maybe the sick person wasn’t quite infectious when on the flight. If true, though, that would be great news.)
“The authorities then traced the other passengers on the flight and didn’t find any that had caught the virus.
If that’s true, that would seem very significant.”
That probably would NOT be due to masks. Airports are a problem but airliners have some of the cleanest air anywhere. The cabin air flows from ceiling to floor and is refreshed 3 times a minute use a mixture of air that has been run thru a HEPA filter and outside air heated to 500 degrees and then cooled.
I strongly suspect places like Arizona and Texas should stop putting attention on masks and place far more attention on public buildings using better filtration for their air conditioning. Texas, Arizona and California saw surges in cases as the weather got hot and people started running their AC 24/7. THAT is probably significant.