The evidence on masks is getting even better — here's what it tells us
after controlling for other factors, countries with cultural norms or policies that supported mask-wearing saw weekly per capita coronavirus mortality increase 16% during outbreaks,
compared with a 62% weekly increase in countries without mask-wearing norms.
Policymakers and public health officials now have evidence from laboratories, models, observations and real-world trials that support mask-wearing to reduce respiratory diseases, including COVID-19.
https://www.alternet.org/2021/09/evidence-for-masks/