It would be a significant understatement that the question of the efficacy of masks in limiting the transmission of COVID has been disputed and divisive since the arrival of the virus. This article seems to be the very latest on the subject. It appears to be impressively researched and its conclusions are clear: Mask wearing works and better masks work better. The key, it seems to me, is that the reported significant positive results were achieved despite utilizing a voluntary mask wearing program that resulted in far less than full compliance yet still achieved significant success. This presumably understates the effectiveness of mask wearing (while still yielding notable results) while also addressing the practical realities of mask wearing in this country at this time.

I do not know if this study qualifies as "definitive" and the article notes that it is still under peer review, but it appears to be well conceived and well executed by researchers with the right range of expertise (and significant credentials, which is of course its own issue in this day and age) and it would take a far greater mind than mind to find significant flaws in it. In any case, read this summary and decide for yourself.

https://www.nytimes.com/2021/09/26/opin ... 029039208a