Everyone should look at the remarkable work done in this cluster randomized trial.
They found that an intervention which increased surgical mask uptake in community settings significantly reduced SARS-CoV-2 infection among older adults.
A thread.
1/6
They found that an intervention which increased surgical mask uptake in community settings significantly reduced SARS-CoV-2 infection among older adults.
A thread.
1/6
https://twitter.com/Jabaluck/status/1433036923610742789
Most people's 1st tendency is to claim studies like this support what they already knew. In reality, the study had specific and not necessarily intuitive findings.
The study even collected predictions from experts, and found that they failed to predict the study outcomes!
2/6
The study even collected predictions from experts, and found that they failed to predict the study outcomes!
2/6
For example, the study found that increasing mask usage had statistically significant effect on SARS-CoV-2 infection.
But these results were driven by surgical mask use, and by reductions in infections in people over 50.
A brief reminder that CDC mask guidelines start at age 2.
But these results were driven by surgical mask use, and by reductions in infections in people over 50.
A brief reminder that CDC mask guidelines start at age 2.
On the other hand, the study did not find a decrease or increase in SARS-CoV-2 infection among the cloth group (Their CI for RR for cloth is [.79,1.11]. Note that this would undercut a hypothesis (not uncommon before 2020) that cloth masks might increase infection rates.
4/6
4/6
Of course, this also undercuts the intervention the U.S. chose to pursue for essentially the entire pandemic.
Even today, the CDC emphasizes cloth masks as the intervention of choice, and the demographic most consistently subjected to mask requirements is children.
5/6
Even today, the CDC emphasizes cloth masks as the intervention of choice, and the demographic most consistently subjected to mask requirements is children.
5/6
One thing we should not take away from a study which conducted a cRCT and found a modest but significant effect on infection in older but not younger adults (and from surgical but not cloth masks) is that trials in schools for masks on children are infeasible or "not needed".
6/6
6/6
Addendum:
It will be interesting to see whether the CDC updates its page collecting observational studies suggesting cloth masks do work (and ignoring those that don't) to include a reference to this RCT, and if they do, how long that will take.
cdc.gov/coronavirus/20…
7/6
It will be interesting to see whether the CDC updates its page collecting observational studies suggesting cloth masks do work (and ignoring those that don't) to include a reference to this RCT, and if they do, how long that will take.
cdc.gov/coronavirus/20…
7/6
And for everyone wondering why there haven't been more such trials, or trials of school mandates, etc, instead of everyone just making other people do things without ever even intending to studying the effects, this sums up the relevant dynamics.
https://twitter.com/ProfEmilyOster/status/1433144305301004294?s=20
No surprise to Twitter is full of two camps of reactions reconciling these differences in effects, one suggesting actually all mask policies probably help at least some in all situations, the other saying not at all in any.
Both camps are anti-scientific.
Both camps are anti-scientific.
https://twitter.com/WesPegden/status/1433091868619952134
• • •
Missing some Tweet in this thread? You can try to
force a refresh
