For professionals (doctors) it works, we know that for a long time. It's not fail safe, but it works.
For the rest of the population it is hard to determine a mask measure works. Even with this study it's hard to determine. Regular people tend to reuse masks too much, not care for quality labels (N95, etc), and not adjust them well.
For the rest of the population it is hard to determine a mask measure works. Even with this study it's hard to determine. Regular people tend to reuse masks too much, not care for quality labels (N95, etc), and not adjust them well.