Day 657: More Mask Myths

I have been pondering for a long time, how our entire response to Corona every day grows more bizarre and detached from any conceivable, realisable goal or rational purpose. I understand why many detect behind this broken response the machinations of evil conspirators, and indeed it often seems that all of this is being managed for maximum chaos and destruction. I’ve tried to offer different explanations: Perverse bureaucratic incentives, managerial blindness and iterative institutional processes surely all play a role here, but a failure this profound will have many facets. — eugyppius

On to the topic of the day: more mask efficacy numbers pulled out of thin air. On this pandemic episode of Sesame Street, the number of the day is 53%. Vinay Prasad fisks this number down to 11% or less:

Interestingly, in the only published cluster RCT [randomized controlled trial] to date during COVID19, surgical masks had an 11% risk reduction and cloth masks had no effect at all on the primary endpoint of symptom driven lab positive results. That cluster RCT took place in a location with essentially no vaccination (aka circumstances which would give masks the best chance to show the best effect size).

The only other completed RCT during the pandemic, DANMASK was null as to the effect of surgical masks, and had been powered to detect a 50% reduction. At the time, many complained DANMASK was underpowered. Masks worked, but not that well, they argued. Yet, it appears now DANMASK was adequately powered if one is to believe the 53% estimate. So which is it? Was DANMASK adequately powered or not? Is 50% plausible or not?

Before you answer, let’s remember that even the authors of the 53% study write, “Risk of bias across the six studies ranged from moderate to serious or critical.” I never thought I would be wishing for ‘mild’!

It goes on like that, and he also co-authored a 25,000-word review of mask research, if you're really, really interested in the topic.

P.S. Massachusetts cases were up four tenths of a percentage point today.