The theory behind universal masking rests on early studies which indicated a possibility of asymptomatic spreaders. This has mostly been falsified in at least

The theory behind universal masking rests on early studies which indicated a possibility of asymptomatic spreaders. This has mostly been falsified in at least one controlled study [1]. The Danish study is the closest thing we have to RCT on masking [2] which found no statistically significant result from universal masking. Wearing a mask while symptomatic seems like a good idea though, if you're unable to stay home for some reason, though that's good advice for most airborne contagious illnesses. I appreciated the culture of doing this when I was in Japan - if for no other reason than it told me who to keep my distance from. [1] https://www.bmj.com/content/371/bmj.m4695 https://www.bmj.com/content/371/bmj.m4695 [2] https://www.acpjournals.org/doi/10.7326/m20-6817 https://www.acpjournals.org/doi/10.7326/m20-6817