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New paper on Masks:
Some claim scientific studies show masks don’t work, or that surgical masks are as good as N95s. Just released paper shows this claim is false. Masks work, and N95 respirators give a much higher benefit than surgical masks.1/
Some claim scientific studies show masks don’t work, or that surgical masks are as good as N95s. Just released paper shows this claim is false. Masks work, and N95 respirators give a much higher benefit than surgical masks.1/
The controversy about N95 respirator and mask efficacy is based on claims that studies (RCTs and meta-analyses) have no observed effect. Our paper shows these claims result from the use of incorrect mathematical equations.2/
The incorrect mathematical equations bias the results. Reanalyzing the data with the right equations show that masks, and N95s in particular, do prevent transmission.
Here are a few highlights of the paper.3/
Here are a few highlights of the paper.3/
1) Studies comparing N95s and surgical masks in healthcare workers ignore infections at home—outside study protocols. This effect is so large, a study claiming N95s give no more than 2X improvement, should instead say no more than 10X improvement, or even higher.4/
2) The study also did not measure how much healthcare worker masking affects patients. Including patients would result in about 2X higher benefit of N95s in preventing infections and even more for reducing harm because of the higher vulnerability of patients.5/
3) The study also did not consider two way masking which would bring the improvement by 10X up to 100X = 10X * 10X due to both the infected individual (source), and the individual who is not infected, wearing an N95 respirator.6/
4) While the studies focus on statistical significance, if we look at the benefit from improved masking, the meta-analyses show there is a high probability of benefit ratio, such as 15X for N95s compared to surgicals.7/
5) If we exclude from the meta-analyses one incorrectly designed study that specified masking within 6 ft of patients (not correct for airborne transmission) then results show there is statistical significance—undermining the claim of no observed effect.8/
Overall, when the equations are corrected, the evidence shows N95s compared to surgical masks, and masks compared to no masks, improve health outcomes by preventing transmission. This is consistent with what is known from other studies about airborne transmission.9/
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