One good mask study has been done.
I am a court-certified expert on survey research and design. Somehow a good study of using masks to prevent Covid-19 was done last year but I didn’t hear about it. ‘Somehow.’ Not really. We have a totally dishonest media and government infrastructure that openly and consciously lies.
I read the Claremont Review of Books. In the latest issue, Summer 2021, there is an article by Jeffrey H. Anderson that tells about a Danish study by 22 medical people of two randomized samples done for two months last year; one group wore masks while the other didn’t. The sample size was 8,000 people, enough to detect any fraction of a percent difference in the number of cases that got Covid-19. There was no significant difference in the two groups.
Meaning, the 120 nanometer virus circulates freely in the air with little or no regard to a face mask.