Fantastic article. Some takeaways:
"Meanwhile, the CDC website portrays the Danish RCT (with its 4,800 participants) as being far less relevant or important than the observational study of Missouri hairdressers with no control group, dismissing the former as “inconclusive” and “too small” while praising the latter, amazingly, as “showing that wearing a mask prevented the spread of infection”—when it showed nothing of the sort."
And:
In sum, of the 14 RCTs that have tested the effectiveness of masks in preventing the transmission of respiratory viruses, three suggest, but do not provide any statistically significant evidence in intention-to-treat analysis, that masks might be useful. The other eleven suggest that masks are either useless—whether compared with no masks or because they appear not to add to good hand hygiene alone—or actually counterproductive. Of the three studies that provided statistically significant evidence in intention-to-treat analysis that was not contradicted within the same study, one found that the combination of surgical masks and hand hygiene was less effective than hand hygiene alone, one found that the combination of surgical masks and hand hygiene was less effective than nothing, and one found that cloth masks were less effective than surgical masks.
Fantastic article. Some takeaways:
"Meanwhile, the CDC website portrays the Danish RCT (with its 4,800 participants) as being far less relevant or important than the observational study of Missouri hairdressers with no control group, dismissing the former as “inconclusive” and “too small” while praising the latter, amazingly, as “showing that wearing a mask prevented the spread of infection”—when it showed nothing of the sort."
And:
In sum, of the 14 RCTs that have tested the effectiveness of masks in preventing the transmission of respiratory viruses, three suggest, but do not provide any statistically significant evidence in intention-to-treat analysis, that masks might be useful. The other eleven suggest that masks are either useless—whether compared with no masks or because they appear not to add to good hand hygiene alone—or actually counterproductive. Of the three studies that provided statistically significant evidence in intention-to-treat analysis that was not contradicted within the same study, one found that the combination of surgical masks and hand hygiene was less effective than hand hygiene alone, one found that the combination of surgical masks and hand hygiene was less effective than nothing, and one found that cloth masks were less effective than surgical masks.
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