Comment by n4r9

> If you narrow it down to just studies that use the scientific method correctly and which are built on strong evidence, no convincing findings remain.

That's a significantly weaker claim than the "masks did nothing" claim you've made in other posts [0-1]. And yes, the Cochrane review stated an inconclusive result; it explicitly doesn't say that masks do nothing. Nor does it really support what you're saying.

Firstly, note that the Cochrane review reviewed the effectiveness of promoting mask-wearing. Not the effectiveness of mask-wearing. It heavily weighted studies with a low (40-50%) adherence to mask-wearing [2]. This limits what it tells us about how well masks work.

Secondly, the Cochrane review arguably overstates its case. There were two randomised controlled trials studying the effectiveness of mask-wearing during the pandemic. The first found that promoting mask-wearing in rural Bangladesh increased mask-wearing by about 30% and reduced the risk of COVID-19-like illness by about 10% [3]. The second found that promoting mask-wearing reduced coronavirus infection by about 18% [4], but the low sample size meant that it could only detect very large effects of 50% of more [5], and the adherence was again low at 46%. Many leading experts in epidemiology believe that this points to a small but worthwhile reduction in COVID transmission when mask-wearing is promoted [6], implying that correctly wearing masks hass a significant effect in reducing transmission.

[0] https://www.factcheck.org/2023/03/scicheck-what-the-cochrane...