> There were significantly fewer COVID-19 cases in villages with surgical masks compared with the control villages. (Although there were also fewer COVID-19 cases in villages with cloth masks as compared to control villages, the difference was not statistically significant.) This aligns with lab tests showing that surgical masks have better filtration than cloth masks. However, cloth masks did reduce the overall likelihood of experiencing symptoms of respiratory illness during the study period.<p>I think this is probably the most interesting part, and worth watching in future studies.
> The researchers enrolled nearly 350,000 people from 600 villages in rural Bangladesh<p>Wow. I was about to complain about "small n", but... an experiment of this size is not small at all. Congrats on the researchers on doing such a big study!
Its interesting that the article do not mention a rather interesting finding in the study. For the age groups of < 50 years the effect was not statistically significant with the control and the mask wearing villages having similar rate of covid-19.<p>Why aren't masks effective to reduce the spread for that age group? The discussion part of the study don't explore it. Is the distancing behavior of people aged 50 or higher different than those below?<p>I would like to see further studies being done on the younger demographic in order to explain why the data is looking like it is.
Here is the paper (or one of them, it is not clear after so many links):<p><a href="https://www.poverty-action.org/sites/default/files/publications/Mask_RCT____Symptomatic_Seropositivity_083121.pdf" rel="nofollow">https://www.poverty-action.org/sites/default/files/publicati...</a><p>Bottom line: "The proportion of individuals with COVID-like symptoms was 7.62% (N=13,273) in the intervention arm and 8.62% (N=13,893) in the control arm. Blood samples were collected from N=10,952 consenting, symptomatic individuals. Adjusting for baseline covariates, the
2 intervention reduced symptomatic seroprevalence by 9.3% (adjusted prevalence ratio (aPR) = 0.91 [0.82, 1.00]; control prevalence 0.76%; treatment prevalence 0.68%). In villages randomized to surgical masks (n = 200), the relative reduction was 11.2% overall (aPR = 0.89 [0.78,
1.00]) and 34.7% among individuals 60+ (aPR = 0.65 [0.46, 0.85]). No adverse events were reported."
Cloth masks are quite effective against viruses with a droplet based spread. Widespread mask use came as close to wiping out last year's Flu season as we've ever seen.<p>>Amid COVID-19 pandemic, flu has disappeared in the US<p>NEW YORK (AP) — February is usually the peak of flu season, with doctors’ offices and hospitals packed with suffering patients. But not this year.<p>Nationally, “this is the lowest flu season we’ve had on record,” according to a surveillance system that is about 25 years old, said Lynnette Brammer of the U.S. Centers for Disease Control and Prevention.<p><a href="https://apnews.com/article/flu-has-disappeared-us-pandemic-2145d999319b53d8a32a829a324f398d" rel="nofollow">https://apnews.com/article/flu-has-disappeared-us-pandemic-2...</a><p>However, during the same period where the Flu disappeared, there was a massive Covid surge, because cloth masks are not an effective means of filtering an airborne virus from the air you breathe.<p>Here's one of the scientists on President Biden's Covid advisory board being interviewed on PBS.<p>>Studies that have been done show that if an individual might get infected within 15 minutes in a room, by time and concentration of the virus in the room, add a face cloth covering you only get about five more minutes of protection.<p>On the other hand if you use the n95 respirators and fit them tight to your face, you can actually spend 25 hours in that same room and still be protected.<p><a href="https://www.pbs.org/wnet/amanpour-and-company/video/do-masks-provide-much-protection-we-think-bglhwy/" rel="nofollow">https://www.pbs.org/wnet/amanpour-and-company/video/do-masks...</a><p>To get the kind of protection people imagine that cloth masks provide, you have to wear the same sort of masks that medical professionals are required to wear while treating patients who have an airborne virus.<p>Which is not surprising since we know Covid is fully airborne.<p>Unfortunately, those of us on the left have rejected this news in the same way that the crowd at a Trump rally rejected Trump when he told them that they should get vaccinated.<p>Cloth masks are not an adequate substitute for vaccination, especially for children too young to be vaccinated who are now expected to attend full school days.
So am I understanding the study correctly?<p>> Those living in villages randomly assigned to a series of interventions promoting the use of surgical masks were about 11% less likely than those living in control villages to develop COVID-19<p>The surgical masks are 11% more effective in preventing COVID infection than not wearing masks at all?
Quite convinced we have to prepare on getting infected some time. Covid will be around for the coming years and years. Nice that you have less chance of getting that, and then what? You can’t walk around with a mask indefinitely.
Saw another report this week that links to the viral load and the impact: low viral load = no symptoms, no immunity. Medium viral load is minimal symptoms, Immunization. High viral load = serious illness (and immunity, but potentially also hospitalisation and/or long covid)
Would be nice if the masks help you to get in the sweet spot.
Reduce but not by much. One could buy KN95 masks at comparable costs and wear them longer and be safer. Not sure why people would get a surgical mask. Governments must subsidize quality masks!
What people seem to be missing is that this study only covered a limited period. While surgical masks can slightly reduce the risk of contagion for individual interactions, over a longer period all of us will eventually be exposed regardless of what precautions we take. The virus isn't going away.<p>Think of it like a soccer goalie defending against an endless series of penalty kicks. He might block the first few balls but eventually one will get through.<p><a href="https://www.businessinsider.com/delta-variant-made-herd-immunity-not-possible-astrazeneca-developer-2021-8" rel="nofollow">https://www.businessinsider.com/delta-variant-made-herd-immu...</a><p>This is why it's so important for people who haven't yet been infected to get vaccinated. And take other steps to strengthen your immune system such as reducing obesity, maintaining adequate vitamin D levels, and engaging in the recommended level of physical activity.<p><a href="https://www.cnbc.com/2021/03/08/covid-cdc-study-finds-roughly-78percent-of-people-hospitalized-were-overweight-or-obese.html" rel="nofollow">https://www.cnbc.com/2021/03/08/covid-cdc-study-finds-roughl...</a><p><a href="https://vitamin-d-covid.shotwell.ca/" rel="nofollow">https://vitamin-d-covid.shotwell.ca/</a><p><a href="https://bjsm.bmj.com/content/early/2021/07/21/bjsports-2021-104203" rel="nofollow">https://bjsm.bmj.com/content/early/2021/07/21/bjsports-2021-...</a>
Things I wish everyone knew and acted on:<p>1. Masks reduce spread (this study)<p>2. Covid-19 is an airborne disease and primarily spread through aerosols<p>3. Being in a poorly ventilated space (even if everyone is masked) with an infected person means a significant chance of being infected.<p>4. While (1) is true for even meh-masks, to prevent infection in (3), you need to be wearing a tight-fitting high quality mask. No beards, no cloth, no surgical. N-95 or better with total seal.
This is truly great news, as we've need some controlled studies.<p>However, _mandates_, literally threatening people with police violence, bodily or financial harm, is not the correct way forward.<p>I think the best solution is improved mandates for airflow. It's a lot easier to improve airflow in a building than it is to police and enforce a mask mandate.
I was militant pro-mask when I was unvaccinated. Now that I'm vaccinated and have no comorbidities, I'm OK with being exposed to COVID-19. In fact, I want to have a mild case of COVID-19 to get natural immunity. Natural immunity seems to be more effective than the vaccine for long lasting immunity.
My first reaction was to consider this as pretty damning of mass use. But when I considered it more I don't think the study is as damning of masks as it is of mask mandates.<p>The problem is only ~30% more people wore masks in the intervention arm of the study. So the best possible outcome, removing 30% from the infection group entirely (essentially taking them out of the population -- a "perfect spherical mask" approximation), is a 30% reduction in cases. Which is substantial, but no one expects masks to be that effective anyway. 11% seems a reasonable ballpark.<p>If everyone had worn masks it would have been easier to measure the effect of just the masks.<p>Still, it's worth considering the big picture. If mask mandates aren't enforced, they're not worth a whole lot. Especially if you have limited political capital to spend.
The problem with this mask business is it treats masks as the only variable. The United States is incredibly unhealthy and most people do not get enough exercise or spend enough time outdoors. It would not surprise me if governments would obtain better results by telling citizens to exercise regularly and eat healthy. Instead it seems like governments are doubling down on a strategy on scaring/bullying out of shape citizens into staying at home afraid.<p>The most rediculous policy of all is governments requiring masks for outdoor exercise.<p>11% is frankly not going to move the needle. I could probably reduce my chance of dying in a vehicle accident by way over 11% by refusing to ride bicycles. It simply isn’t meaningful.
It wasn't the mask wearing it was the distancing when I was in the military mission oriented personal protection taught us never to issue surgical masks when they're touched they're contaminated and need to be thrown out.<p>ITT: either this place is turned into Reddit with a bunch of retards bots or none of you can read statistics or can even do basic math.
Is to possible to measure or control for behavioral, vs direct transmission blocking, effects of masks? If they seem more effective for old people, could it be that they help remind people about the ongoing pandemic and infection risk, and signal that mask wearers prefer to keep distance to others.
without controlling for average time spent at various distances it seems hard to get any conclusion from this.<p>if wearing a mask results in people staying away from you, is the mask effective, or is <i>distance</i> effective?
Does the paper reveal the seroprevalence by control village and intervention village? I just scanned it and can find no such information.<p>EDIT: Table A14 is the closest I can find but it is only coefficients, not the underlying counts.
From Martin Kulldorff, esteemed (though contrarian) Harvard Med epidemiologist:<p>"Odd that mask advocates are excited by this study. As a vaccine advocate, I would be horrified if a vaccine trial showed 11% efficacy. Based on the 95% confidence intervals, we do not even know if surgical mask efficacy is more than 0%."<p><a href="https://twitter.com/MartinKulldorff/status/1433202651106201607?s=20" rel="nofollow">https://twitter.com/MartinKulldorff/status/14332026511062016...</a>