A lot of the evidence cited here is of very low quality/interest, such as observational and correlational studies. It does cite the best study we have so far, a large-scale RCT from Bangladesh:<p>> A report in Nature explained that researchers running a randomized controlled trial (RCT) of community mask use in Bangladesh “began by developing a strategy to promote mask wearing, with measures such as reminders from health workers in public places. This ultimately tripled mask usage, from only 13% in control villages to 42% in villages where it was encouraged”, and “then compared numbers of COVID-19 cases in control villages and the treatment communities”. They found that the number of infections in mask wearing communities decreased, with a reduction of COVID symptoms using surgical masks to 0.87 times the incidence in unmasked communities, and 0.91 times when using cloth masks.<p>Unfortunately they have misquoted the numbers here. Surgical masks reduced the prevalence of COVID-like symptoms by 11%, and of actual confirmed COVID cases by 9.5%, while cloth masks did about half as well [0]. So tripling the number of people wearing masks up to about 40% of the population has a very mild effect on COVID spread, and this is before Omicron. I don't think this makes a good case for mask mandates in 2022.<p>[0] <a href="https://www.science.org/doi/10.1126/science.abi9069" rel="nofollow">https://www.science.org/doi/10.1126/science.abi9069</a>