https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD...
Unlike your study from November 2020, this one is from January 2023.
That's why this really simple thing became so controversial. I mean, if a virus sticks to droplets then it's better to put less droplets into the air. Masks do that. Easy? Should be.
As for what mask do, if it was that easy, there wouldn't be the need of so many studies. But that is not even the claim here. The article says mask mandates make no difference.
Even if we assume that masks work, people wear them wrongly, they reuse them instead of using clean ones, fidget with them and then touch other parts of their face. There are plenty of reasons why a mandate could not work.
> The high risk of bias in the trials, variation in outcome measurement, and relatively low adherence with the interventions during the studies hampers drawing firm conclusions
Source: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD...
They asked people to wear masks, and they didn't wear masks, so they had trouble concluding things about masks.
This New York Times article prompted the Cochrane review to issue a statement:
> The Cochrane Review 'Physical interventions to interrupt or reduce the spread of respiratory viruses' was published in January 2023 and has been widely misinterpreted.
Source: https://www.cochrane.org/news/statement-physical-interventio...
https://www.cochrane.org/news/statement-physical-interventio...
> Many commentators have claimed that a recently-updated Cochrane Review shows that 'masks don't work', which is an inaccurate and misleading interpretation.
"It would be accurate to say that the review examined whether interventions to promote mask wearing help to slow the spread of respiratory viruses, and that the results were inconclusive. Given the limitations in the primary evidence, the review is not able to address the question of whether mask-wearing itself reduces people's risk of contracting or spreading respiratory viruses."
https://www.nytimes.com/2023/02/21/opinion/do-mask-mandates-...