@flaviaritt
Might be interesting for some people on this thread to read the research that came out in Denmark today on masks. It suggests that (contrary to what the WHO have been saying) there isn’t actually a significant protective effect for the wearer. There still appears to be a protective effect in terms of likelihood of transmission to someone else.
It’s interesting how quickly people appeal to certainty and “consensus” - using such things to call other people stupid or malicious - when, actually (IMO) it’s their own inability to deal with uncertainty that is the issue.
It's interesting that you use the word "certainty" in relation to this paper, because that's exactly what it lacks.
From the paper:
“The most important limitation is the that the findings are inconclusive.”
“Yet, the findings were inconclusive and cannot definitively exclude a 46% reduction to a 23% increase in infection of mask wearers in such a setting.”
Limitations were:
“Inconclusive results, missing data, variable adherence, patient-reported findings on home tests, no blinding, and no assessment of whether masks could decrease disease transmission from mask wearers to others.”
It does not suggest that "there isn’t actually a significant protective effect for the wearer". All it shows that, given the specific design of this study, no significant difference was found between mask-wearing and control in terms of protection from infection.
Because of the small sample size, the confidence interval of the results was huge and, based on this data, the effect of mask wearing could range from a 46% decrease in infection to a 23% increase in infection. That is very inconclusive.
All we can conclude is that, in places where infection rates are generally low, and other protective measures are in place, this specific mask recommendation made during the SARS-CoV-2 pandemic, with background rates of 2% PCR acquisition, failed to show that mask wearing reduces risk by 50%. It may have reduced risk by 46%. It may have increased risk by 23%. Or somewhere in between. We don’t know, because of the way the study was designed and the results they got.
The study also did not test for the effect of mask-wearing in infection rates of other people, which is one of the big claims of mask-wearing.
So, while interesting, this paper doesn't add a great deal to the body of evidence around mask-wearing, and has been widely misinterpreted as evidence that 'masks don't work'.