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Comment by jjgreen | Hacker News Reader

The DANMASK19 experiment, the only RCT on mask effectiveness so far I believe, found no statistical significance on masks protecting the wearer. I wonder if the English demasking would be a good time for a follow-up: we have climbing infections and the change in the law will mean we can have a cohort in each camp; ENGMASK21 if you like. To not do it would seem to be a missed opportunity. Any takers?

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The DANMASK study did NOT find that masks are not effective. It’s conclusion was that a recommendation for surgical masks in certain settings does not prevent more than 50% of infections in the wearer in a country with low case load and before any variants but that there even was a tendency towards a protective effect. So not at all meaningful in any way. What does this say about the ability of N95/FFP2 masks when all parties are wearing them to reduce the R of delta sufficiently to contain spread in communities that are seeing surges? Exactly nothing.

Furthermore, designing an RCT for mask use might not really be doable in a fashion we’re used to from drug interventions. And should the vast amount of other non-RCT evidence that does exist and that shows a protective effect of masks as well as the precautionary principle not lead us all to mask up in the face of a new disease that is proven to cause serious harm, short and long term?

For anybody interested in the topic, this thread by an Oxford professor and co-author of the recent Lancet letter advising against the plans of the British government might be worthwhile reading: https://twitter.com/trishgreenhalgh/status/14142940034790891...

Edit: Typo.

The mask is to prevent unknowing infected from transferring the disease. It was never to protect FROM covid19

That's the narrative now, but a year ago there were plenty of people in the government, press and academia with a different view, https://www.ox.ac.uk/news/2020-07-08-oxford-covid-19-study-f... for example

In early 2020 it was still a common opinion that SARS-CoV2 mainly spread through droplets, in that case surgical masks would have been sufficient to offer the wearer some protection. However by late Spring/early Summer (northern hemisphere) it became apparent that it was airborne which is why all medical personal switched to FFP2 masks (long before the CDC and the WHO officially recognized it as being airborne). Confusion only arose because many actors were reluctant in accepting airborne transmission and thus kept recommending the wrong type of mask for personal protection. But nowadays there’s no doubt about airborne transmission and you can get good quality FFP2 masks for around 2$ and studies show that even exercising with them is not a problem.

Don't pay attention to dumb narratives. Government, press as well as academia serve themselves. Why would you blindly trust what they say? The relevant science was publicly on the web, and it was always clear from all relevant research that masks are there to stop the wearer from spreading; any doctor would've told you, they are taught about it in school. It was the narrative in many other countries for way over a year, if that's what you must look for (e.g. "chráníš mě, chráním tebe" - I protect you, you protect me - is the official governmental stance in Czechia since March 2020).

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