[Mouse47]

>In the study, which was carried out in April and May when Danish authorities did not recommend wearing face masks, 6,024 adults were divided into two groups, one wearing face masks and one control group.

>After one month, 1.8% of the people wearing masks had been infected, while 2.1% of the people in the control group had tested positive, Copenhagen University Hospital said in a press release.

>The study does not confirm the expected halving of the risk of infection for people wearing face masks

>Participants reported their own test results; mask use was not independently verified, and users may not have worn them correctly.

So the control group had no masks, and the mask group were only told to wear a mask, and we have no data for how often they wore it. If their behavior is anything like what I'm seeing in the U.S., they're wearing it into the grocery store and going and seeing friends normally without a mask. The fact the study still produced a (likely statistically insignificant) 15% reduction in risk (1.8/2.1) is surprising under these circumstances.

[frumiousirc]

> the mask group were only told to wear a mask

They were asked if and how they followed instructions and the 7% that said they did not were removed from the analysis. Only half of the remaining said they followed instructions. I also doubt the veracity of the replies. This is a weak point of the procedure.

[happytoexplain]

I'm confused as to why they removed that 7%. Are they or are they not trying to test the effect of advisement? If that really was the goal, then the veracity of replies wouldn't matter, and the study would make sense - but then they also wouldn't have omitted that 7%.

[Symmetry]

It isn't clear that the people in the control group didn't wear masks. Few Danish people were wearing masks then but I'd imagine that people who went and volunteered for this study would be more likely to be the sort of people who would go and get their own masks if they weren't given them.

[me_me_me]

0.3% better chance for wearing a piece of cloth over a face - for a mild inconvenience. I'll take it anytime still.

I've seen accounts of maraton runners not able to run a 1K months after recovering.

I'll take 0.3% over nothing, thanks.

Also noteworthy, that is 10% less of a chance of getting infected. If you were to get infected.