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Except that was not what was tested. Here is what they did: >No-cost free masks distribution - One-third of the intervention villages received a cloth mask an

by slg 5y ago

Except that was not what was tested. Here is what they did: >No-cost free masks distribution - One-third of the intervention villages received a cloth mask and two-thirds of the intervention villages received a surgical mask[5] during household distribution and distribution at marketplaces and other public locations weekly or every fortnight. Masks were also distributed at mosques on three Fridays during the first four weeks of the intervention. >Offering information on mask-wearing - Along with the distribution, the research team showed a brief video of notable public figures discussing why, how, and when to wear a mask. The video featured the Honorable Prime Minister of Bangladesh Sheikh Hasina, the head of the national Imam Training Academy, and the national cricket star Shakib Al Hasan. During the distribution visit, households also received a brochure based on WHO materials depicting proper mask wearing. >Reinforcement in-person and in public - In an effort to create a social norm, mask promoters encouraged non-mask wearers to wear a mask, providing a mask if the individual did not have one. Mask promoters also played public service announcements in public areas using handheld microphones. >Modeling and endorsement by trusted leaders. - Religious leaders (imams) discussed the importance of mask-wearing at Friday prayers from a scripted speech provided by the research team. This is a test of the effectiveness of these public policies and not the effectiveness of masks in general.

kragen 5y ago
Hmm, are you suggesting that those public policies might have had an impact on covid transmission that wasn't mediated through mask-wearing? For example, having the imams discuss the importance of mask-wearing might discourage people from going to Friday prayers? That seems unlikely but conceivable.
- Volundr 5y ago
  Not really. What's being suggested is that what's being tested is both societal compliance combined with mask effectiveness. To dramatically over simplify, let's assume we have a population of 10, none of them mask wearers. Let's also assume masks are 100% effective at preventing Covid infection. These measures convince only 1 person to wear a mask. In the control group (no advocacy) 10/10 are infected. In the study group 9/10 are because that one person wore a mask. So we've got an effectiveness of 10%, despite masks in our contrived example being 100% effective. The effectiveness is blunted by lack of compliance.
- slg 5y ago
  >Hmm, are you suggesting that those public policies might have had an impact on covid transmission that wasn't mediated through mask-wearing? That wasn't the intention of my comment, but yes that is also true. As the article notes: >"In the intervention villages, they also saw a slight increase in physical distancing in public spaces, such as marketplaces." My original comment was more directed at the fact that these public policies are not 100% effective in getting people to wear masks. Therefore the society reduction of 11% is not comparable to the vaccine efficacy numbers which are measured at an individual level. If we measured vaccine efficacy numbers using this societal approach, the numbers in the US would be abysmal considering our active case numbers are quickly approaching the peak of the pre-vaccine waves.
timr 5y ago
They did all of those things, but this paper is about the effect of mask-wearing (surgical vs. cloth vs. none) on the rate of symptomatic seroprevalence in the groups. Kuldorff is right, and is just stating the top-line numbers from the paper.
- slg 5y ago
  >Free mask distribution and promotion reduced the proportion of people who reported COVID-like symptoms on average by 11 percent, which was driven mainly by the effects of surgical masks. Villages where cloth masks were distributed experienced a 5 percent reduction in symptoms, while villages where surgical masks were distributed saw a reduction of 12 percent. About a third (40 percent) of those who reported COVID-19 symptoms agreed to have their blood tested for SARS-CoV-2. On average, researchers found a decrease of symptomatic SARS-CoV-2 infections of 9 percent. This reduction was higher in villages that wore a surgical mask (11 percent) and in these, among individuals aged 60+ (35 percent). It is measuring the effectiveness of the public policy and comparing how it differs when the masks distributed were cloth versus surgical. There is nothing in this report about the effectiveness of masks on an individual level.
  - chitowneats 5y ago
    "This report" does gloss over much of the results from the actual study. Here's the link to the paper: https://www.poverty-action.org/sites/default/files/publications/Mask_RCT____Symptomatic_Seropositivity_083121.pdf https://www.poverty-action.org/sites/default/files/publicati...
  - worker767424 5y ago
    And at 9%, some of that is likely seeing trusted public figures essentially saying "it's not safe out there" by talking about masks, and people restricting their actions accordingly. It's really hard to actually test this.
  - timr 5y ago
    > There is nothing in this report about the effectiveness of masks on an individual level. The DANMASK RCT [1] provided a direct test of masks as personal protective equipment, and found no support for masks. The criticism of that study, at that time, was that it didn't test the hypothesis of protecting others. So here we have an RCT that tests that hypothesis, and now that's not good enough, because the results aren't "at an individual level"? Boy, the ground sure is slippery around here! [1] https://www.acpjournals.org/doi/10.7326/M20-6817 https://www.acpjournals.org/doi/10.7326/M20-6817

by slg 5y ago

kragen 5y ago

Hmm, are you suggesting that those public policies might have had an impact on covid transmission that wasn't mediated through mask-wearing? For example, having the imams discuss the importance of mask-wearing might discourage people from going to Friday prayers? That seems unlikely but conceivable.

Volundr 5y ago
Not really. What's being suggested is that what's being tested is both societal compliance combined with mask effectiveness. To dramatically over simplify, let's assume we have a population of 10, none of them mask wearers. Let's also assume masks are 100% effective at preventing Covid infection. These measures convince only 1 person to wear a mask. In the control group (no advocacy) 10/10 are infected. In the study group 9/10 are because that one person wore a mask. So we've got an effectiveness of 10%, despite masks in our contrived example being 100% effective. The effectiveness is blunted by lack of compliance.
slg 5y ago
>Hmm, are you suggesting that those public policies might have had an impact on covid transmission that wasn't mediated through mask-wearing? That wasn't the intention of my comment, but yes that is also true. As the article notes: >"In the intervention villages, they also saw a slight increase in physical distancing in public spaces, such as marketplaces." My original comment was more directed at the fact that these public policies are not 100% effective in getting people to wear masks. Therefore the society reduction of 11% is not comparable to the vaccine efficacy numbers which are measured at an individual level. If we measured vaccine efficacy numbers using this societal approach, the numbers in the US would be abysmal considering our active case numbers are quickly approaching the peak of the pre-vaccine waves.

timr 5y ago

They did all of those things, but this paper is about the effect of mask-wearing (surgical vs. cloth vs. none) on the rate of symptomatic seroprevalence in the groups. Kuldorff is right, and is just stating the top-line numbers from the paper.

slg 5y ago
>Free mask distribution and promotion reduced the proportion of people who reported COVID-like symptoms on average by 11 percent, which was driven mainly by the effects of surgical masks. Villages where cloth masks were distributed experienced a 5 percent reduction in symptoms, while villages where surgical masks were distributed saw a reduction of 12 percent. About a third (40 percent) of those who reported COVID-19 symptoms agreed to have their blood tested for SARS-CoV-2. On average, researchers found a decrease of symptomatic SARS-CoV-2 infections of 9 percent. This reduction was higher in villages that wore a surgical mask (11 percent) and in these, among individuals aged 60+ (35 percent). It is measuring the effectiveness of the public policy and comparing how it differs when the masks distributed were cloth versus surgical. There is nothing in this report about the effectiveness of masks on an individual level.
- chitowneats 5y ago
  "This report" does gloss over much of the results from the actual study. Here's the link to the paper: https://www.poverty-action.org/sites/default/files/publications/Mask_RCT____Symptomatic_Seropositivity_083121.pdf https://www.poverty-action.org/sites/default/files/publicati...
- worker767424 5y ago
  And at 9%, some of that is likely seeing trusted public figures essentially saying "it's not safe out there" by talking about masks, and people restricting their actions accordingly. It's really hard to actually test this.
- timr 5y ago
  > There is nothing in this report about the effectiveness of masks on an individual level. The DANMASK RCT [1] provided a direct test of masks as personal protective equipment, and found no support for masks. The criticism of that study, at that time, was that it didn't test the hypothesis of protecting others. So here we have an RCT that tests that hypothesis, and now that's not good enough, because the results aren't "at an individual level"? Boy, the ground sure is slippery around here! [1] https://www.acpjournals.org/doi/10.7326/M20-6817 https://www.acpjournals.org/doi/10.7326/M20-6817