4 ms·

I don't know that I see the point of this study. First, it's not testing the efficacy of wearing a mask: it's testing the efficacy of telling someone to wear a

I don't know that I see the point of this study. First, it's not testing the efficacy of wearing a mask: it's testing the efficacy of telling someone to wear a mask. This is explicitly stated in the "limitations" section. Second, getting a decent control group is almost impossible. Essentially no one in modern society is unaware of COVID or the recommendation to wear a mask, and essentially no one had failed to form an opinion on whether or not they will comply with that recommendation. And indeed, "variable adherence" is another factor called out in the limitations. The summary could be reworded "having one more doctor tell someone to wear a mask does not make them less likely to contract COVID-19." This study is very much not about the efficacy of state- or nation- wide mask mandates.

petertodd 6y ago
They asked about compliance: > Based on the lowest adherence reported in the mask group during follow-up, 46% of participants wore the mask as recommended, 47% predominantly as recommended, and 7% not as recommended." Personally, I find it easy to believe that people were in fact wearing their masks. To be in the study you it looks like you had to joined voluntarily on your own accord, indicating a participant group with an interest in it: > Recruitment involved media advertisements and contacting private companies and public organizations If anything, I find it easy to believe that adherence would be less in the general population than in this study. Particularly stuff like wearing masks incorrectly, eg not covering the nose, leaving gaps, etc.
- sterlind 6y ago
  How many people in the control group wore masks? It's not like they were told not to wear masks, they just weren't told to. Edit: it actually looks like the study doesn't include that statistic at all, which is appallingly poor design.
  - censorshipsci 6y ago
    Did you check the supplemental materials?
  - goto11 6y ago
    > It's not like they were told not to wear masks, they just weren't told to. Why do you think that? The study says "A total of 3030 participants were randomly assigned to the recommendation to wear face masks, and 2994 were assigned not to wear face masks".
nabla9 6y ago
>During the study period (3 April to 2 June 2020), Danish authorities did not recommend use of masks in the community and mask use was uncommon (<5%) outside hospitals (22).
tinus_hn 6y ago
No, the study would only be worthwhile if it fitted the narrative and proved the usefulness of masks. Otherwise its time to break out the excuses.
- weakfish 6y ago
  Sounds like you're the one making excuses. Anti intellectualism is strong in this thread.
- nabla9 6y ago
  The study is not about usefulness of wearing mask during epidemic. It's limited to the usefulness of wearing surgical mask to protect the wearer. There is lots of evidence that wearing mask protects others, that's why surgeons wear surgical masks during surgery. Surgical masks are not intended to protect the wearer, you need medical respirator for that. The question is how effective they are in doing job they are not designed to do. It seems to be limited, maybe around 30-50% depending on the study.
  - petertodd 6y ago
    > There is lots of evidence that wearing mask protects others, that's why surgeons wear surgical masks during surgery. There is a lack of evidence for the effectiveness of masks during surgery, and they aren't always mandatory to wear: https://www.cochrane.org/CD002929/WOUNDS_disposable-surgical-face-masks-preventing-surgical-wound-infection-clean-surgery https://www.cochrane.org/CD002929/WOUNDS_disposable-surgical... https://www.medpagetoday.com/infectiousdisease/infectioncontrol/16278 https://www.medpagetoday.com/infectiousdisease/infectioncont... https://ncbi.nlm.nih.gov/pmc/articles/PMC4480558/ https://ncbi.nlm.nih.gov/pmc/articles/PMC4480558/ There are obvious hygienic benefits - no-one wants to be splashed with bodily fluids - but there is a lack of evidence that they actually protect the patient.
jimrandomh 6y ago
> The summary could be reworded "having one more doctor tell someone to wear a mask does not make them less likely to contract COVID-19." That's not an accurate summary; that should be "having one more doctor tell someone to wear a mask does not have a large enough effect size on their likelihood of getting COVID-19 for this study to detect." They had 1.8% infected in the extra-recommendation group and 2.1% in the control group.
goto11 6y ago
> Essentially no one in modern society is unaware of COVID or the recommendation to wear a mask At the time the study was performed (April and May 2020), it was not common to wear masks in Denmark outside of hospitals. In fact the authorities recommended against wearing masks because there was a shortage and the available masks should be reserved for high risk groups.

petertodd 6y ago

They asked about compliance: > Based on the lowest adherence reported in the mask group during follow-up, 46% of participants wore the mask as recommended, 47% predominantly as recommended, and 7% not as recommended." Personally, I find it easy to believe that people were in fact wearing their masks. To be in the study you it looks like you had to joined voluntarily on your own accord, indicating a participant group with an interest in it: > Recruitment involved media advertisements and contacting private companies and public organizations If anything, I find it easy to believe that adherence would be less in the general population than in this study. Particularly stuff like wearing masks incorrectly, eg not covering the nose, leaving gaps, etc.

sterlind 6y ago
How many people in the control group wore masks? It's not like they were told not to wear masks, they just weren't told to. Edit: it actually looks like the study doesn't include that statistic at all, which is appallingly poor design.
- censorshipsci 6y ago
  Did you check the supplemental materials?
- goto11 6y ago
  > It's not like they were told not to wear masks, they just weren't told to. Why do you think that? The study says "A total of 3030 participants were randomly assigned to the recommendation to wear face masks, and 2994 were assigned not to wear face masks".

nabla9 6y ago

>During the study period (3 April to 2 June 2020), Danish authorities did not recommend use of masks in the community and mask use was uncommon (<5%) outside hospitals (22).

tinus_hn 6y ago

No, the study would only be worthwhile if it fitted the narrative and proved the usefulness of masks. Otherwise its time to break out the excuses.

weakfish 6y ago
Sounds like you're the one making excuses. Anti intellectualism is strong in this thread.
nabla9 6y ago
The study is not about usefulness of wearing mask during epidemic. It's limited to the usefulness of wearing surgical mask to protect the wearer. There is lots of evidence that wearing mask protects others, that's why surgeons wear surgical masks during surgery. Surgical masks are not intended to protect the wearer, you need medical respirator for that. The question is how effective they are in doing job they are not designed to do. It seems to be limited, maybe around 30-50% depending on the study.
- petertodd 6y ago
  > There is lots of evidence that wearing mask protects others, that's why surgeons wear surgical masks during surgery. There is a lack of evidence for the effectiveness of masks during surgery, and they aren't always mandatory to wear: https://www.cochrane.org/CD002929/WOUNDS_disposable-surgical-face-masks-preventing-surgical-wound-infection-clean-surgery https://www.cochrane.org/CD002929/WOUNDS_disposable-surgical... https://www.medpagetoday.com/infectiousdisease/infectioncontrol/16278 https://www.medpagetoday.com/infectiousdisease/infectioncont... https://ncbi.nlm.nih.gov/pmc/articles/PMC4480558/ https://ncbi.nlm.nih.gov/pmc/articles/PMC4480558/ There are obvious hygienic benefits - no-one wants to be splashed with bodily fluids - but there is a lack of evidence that they actually protect the patient.

jimrandomh 6y ago

> The summary could be reworded "having one more doctor tell someone to wear a mask does not make them less likely to contract COVID-19." That's not an accurate summary; that should be "having one more doctor tell someone to wear a mask does not have a large enough effect size on their likelihood of getting COVID-19 for this study to detect." They had 1.8% infected in the extra-recommendation group and 2.1% in the control group.

goto11 6y ago

> Essentially no one in modern society is unaware of COVID or the recommendation to wear a mask At the time the study was performed (April and May 2020), it was not common to wear masks in Denmark outside of hospitals. In fact the authorities recommended against wearing masks because there was a shortage and the available masks should be reserved for high risk groups.