A shit ton of caveats
We’re not done yet.
Digby referenced on Friday a tweet thread critiquing the recent Cochrane study on masking that has the right wing huffing and puffing even louder, “Masks don’t work!” Bret Stephens in the New York Times brought eye-popping attention this week to Cochrane’s overstated findings by quoting multiple masks-don’t-work and make-no-difference statements.
Then, buried down in paragraph 10, we find “the analysis does not prove that proper masks, properly worn, had no benefit at an individual level.”
Whoa! What?
Kelsey Piper at Vox points out in the meta-analysis that most of the “randomised controlled studies” among Cochrane’s 78 are not about Covid, were not performed during the Covid-19 pandemic (or other epidemics), and only two were “about Covid and masking in particular.” They are examining the effect of mask mandates on community-level spread, not individual protection, as Stephens thoughtfully dropped into paragraph 10.
Furthermore (Cochrane itself):
Our confidence in these results is generally low to moderate for the subjective outcomes related to respiratory illness, but moderate for the more precisely defined laboratory‐confirmed respiratory virus infection, related to masks and N95/P2 respirators.
The observed lack of effect of mask wearing in interrupting the spread of influenza‐like illness (ILI) or influenza/COVID‐19 in our review has many potential reasons, including: poor study design; insufficiently powered studies arising from low viral circulation in some studies; lower adherence with mask wearing, especially amongst children; quality of the masks used; self‐contamination of the mask by hands; lack of protection from eye exposure from respiratory droplets (allowing a route of entry of respiratory viruses into the nose via the lacrimal duct); saturation of masks with saliva from extended use (promoting virus survival in proteinaceous material); and possible risk compensation behaviour leading to an exaggerated sense of security …
That’s a shit ton of caveats.
To make a point about taking such studies with a grain of salt (and about reading before sharing), well:
You’re welcome.
Update: Fixed spelling on Bret Stephens’ name. Hate getting those wrong.