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The third sentence here (and the article's main claim and headline) do not follow from the first two sentences (or from the study they summarise). https://twitter.com/SpecCoffeeHouse/status/1329336770308214786
There are two ways in which mask usage might prevent the spread of the disease in the community: by reducing the chance of mask wearers being infected, and by reducing the chance of mask wearers infecting others.
My impression is that most mask advocates believe that the second mechanism is the main way in which masks are likely to reduce community spread.
But the Danish study does not test this (and cannot, by the nature of its research design).
For this reason, one simply cannot infer that "any effect masks have on preventing the spread of the disease in the community is small" from this research.
(The way to try to test this in a RCT would be to have a team of contact tracers associated with the study, who would follow up on any cases of COVID-19 within the study groups, and compare the number of cases *among downstream contacts* between mask-wearers and non-mask wearers)
(There would be a lot of potential pitfalls in this research design, but it would at least be studying the *right category of thing* to enable us to draw *the category of conclusion* drawn in this Spectator article.)
I guess I'll go ahead and also embed my earlier thread on one of this article's co-authors. https://twitter.com/Lafargue/status/1284837011518439424
I don't think there's really any fair way to characterise this Spectator piece other than ~extremely dishonest~
Quite shocked actually that they're being this brazen.
