https://www.thelancet.com/journals/lancet/article/PIIS0140-6...
> The use of face masks was protective for both health-care workers and people in the community exposed to infection, with both the frequentist and Bayesian analyses lending support to face mask use irrespective of setting. Our unadjusted analyses might, at first impression, suggest use of face masks in the community setting to be less effective than in the health-care setting, but after accounting for differential N95 respirator use between health-care and non-health-care settings, we did not detect any striking differences in effectiveness of face mask use between settings. The credibility of effect-modification across settings was, therefore, low. Wearing face masks was also acceptable and feasible. Policy makers at all levels should, therefore, strive to address equity implications for groups with currently limited access to face masks and eye protection.
The onus is on the "they're dangerous!" folks now.
> However, the authors note that the findings on face masks and eye protection are based on limited evidence.
So limited that this finding was "low confidence". And that's for optimal use of N95 masks, not for fluid resistant surgical masks or cloth masks.
Here's what the actual study said:
> From a policy and public health perspective, current policies of at least 1 m physical distancing seem to be strongly associated with a large protective effect, and distances of 2 m could be more effective. These data could also facilitate harmonisation of the definition of exposed (eg, within 2 m), which has implications for contact tracing. The quantitative estimates provided here should inform disease-modelling studies, which are important for planning pandemic response efforts. Policy makers around the world should strive to promptly and adequately address equity implications for groups with currently limited access to face masks and eye protection. For health-care workers and administrators, our findings suggest that N95 respirators might be more strongly associated with protection from viral transmission than surgical masks. Both N95 and surgical masks have a stronger association with protection compared with single-layer masks. Eye protection might also add substantial protection. For the general public, evidence shows that physical distancing of more than 1 m is highly effective and that face masks are associated with protection, even in non-health-care settings, with either disposable surgical masks or reusable 12–16-layer cotton ones, although much of this evidence was on mask use within households and among contacts of cases. Eye protection is typically under considered and can be effective in community settings. However, no intervention, even when properly used, was associated with complete protection from infection. Other basic measures (eg, hand hygiene) are still needed in addition to physical distancing and use of face masks and eye protection.
Even the bit you're quoting says "face masks are associated with protection, even in non-health-care settings".
What's the control group?
Here's what the paper says about the evidence:
> Further high-quality research, including randomised trials of the optimum physical distance and the effectiveness of different types of masks in the general population and for health-care workers' protection, is urgently needed.
People who don't wear masks?
"We need more studies" is not the same as "our own study is bullshit". It's a simple statement of "there's something here that needs further confirmation".
In the meantime, I'm wearing a mask based on preliminary results, and the abject lack of "masks are actively dangerous" studies of any quality the anti-mask folks can refer to as a counterpoint.