Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror
×
Medicine

Masks are Effective, Despite One Flawed Study From Denmark (adn.com) 152

"I think the overwhelming body of evidence suggests that masks are effective," the lead author of a study recently cited by America's Center for Disease Control told the Washington Post.

They were responding to another (very controversial) outlier study whose findings "conflict with those from a number of other studies," according to the New York Times, citing numerous experts. "Critics were quick to note [that] study's limitations, among them that the design depended heavily on participants reporting their own test results and behavior, at a time when both mask-wearing and infection were rare in Denmark."

The Washington Post reports: In the large, randomized study published Wednesday in the Annals of Internal Medicine, researchers observed more than 6,000 people in Denmark from April to June when mask-wearing was not required in the country. Fewer people in the group that was advised to wear masks contracted the virus — or about a 14 percent reduced risk because of mask-wearing — but the difference was not statistically significant, indicating that the medical masks issued were not particularly effective at preventing the wearers from being infected. Other experts, however, argue that the study was conducted when there was relatively less community spread of the virus and that testing the participants' antibodies cannot reliably measure whether they had the virus during the time of the study.

"We think you should wear a face mask at least to protect yourself, but you should also use it to protect others," lead author Henning Bundgaard told The Washington Post. "We consider that the conclusion is we should wear face masks." Bundgaard said even the small risk reduction masks offer "is very important, considering it is a life-threatening disease..."

"Because the issue has become so politicized, there's a real risk — and it's already being used in this way — that studies like this will be sort of cherry-picked and presented as conclusive evidence that masks are completely ineffective," Columbia University virologist Angela Rasmussen said... In letters and blog posts, public health experts express concern about the design of the study and warn that policymakers could misinterpret the research to mean that masks are ineffective. "However, the more accurate translation is that this study is uninformative regarding the benefits (or lack thereof) of wearing masks outside of the healthcare setting," one letter states. "As such, we caution decision-makers and the media from interpreting the results of this trial as being anything other than artifacts of weak design."

Even the Denmark study itself acknowledged its own limitations, citing "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."

And it also acknowledges large gaps in adherence to proper mask usage among its participants: "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."

The Post notes that America's Center for Disease Control reiterated that people do benefit from wearing a mask that can filter out virus-carrying droplets, and last week "cited multiple studies evaluating mechanical evidence that concluded masks can block certain respiratory particles, depending on the material of the mask..."
This discussion has been archived. No new comments can be posted.

Masks are Effective, Despite One Flawed Study From Denmark

Comments Filter:
  • by Carewolf ( 581105 ) on Saturday November 21, 2020 @10:37AM (#60750798) Homepage

    It tested if the masks protected the wearer, but that is not the reason they are recommended or what most masks are designed for. It is to protect everybody else _from_ the wearer, which wasn't tested in this flawed test.

    • by DrMrLordX ( 559371 ) on Saturday November 21, 2020 @10:39AM (#60750802)

      N95 masks protect both wearer and everyone around them. They're the best option.

      • by gweihir ( 88907 )

        Indeed. That is why as soon as they were not scarce anymore (because the medical community needed them), I got a bunch. And I am wearing them, people that fear other wearing masks be damned.

      • N95 masks protect both wearer and everyone around them. They're the best option.

        That really depends on what type of N95 mask you're talking about. Respirators are also masks, but they have unfiltered exhaust ports. (And both a simple mask-plus-exhaust-port and a full-fledged respirator with filter cartridges are called a "respirator", just to further confuse the issue.)

      • by gchat ( 747883 )
        Small correction. Not the ones with the valve. They protect only the wearer while allowing him to breathe more easily. Any breath he exhales isn't filtered at all.
      • Re: (Score:3, Interesting)

        Typical N95 or equivalent or better respiratory protection (what is called PPE -- Personal Protective Equipment) is designed to protect the Person wearing the respirator from external hazards. Surgical/Procedure/Cloth masks are not PPE, they are OPE (Other Protective Equipment). They are used to protect Other persons from the respiratory hazards of the wearer.

        Proper respirators (PPE) are "destination control". Loose fitting cloth/surgical/procedure masks (OPE) are "source control".

        The Denmark study teste

      • How do they protect the wearer?

        Mind you, you cannot usethe behavior of trained specialist as an argument. But only that of the "average person", that will touch the shopping cart handle and door handle and with her hands, then touch the inside of the mask while taking it off, five seconds late, carrying germs over, to put the mask on when entering the next shop, to put the germs onto the next cart or handle or button. Every time they breathe in, the air passed the now germ-infested humid inside of the mask,

        • "How do they protect the wearer?"

          By reducing the probability of inhaling the virus, and reducing the dosage when the virus is inhaled.

          The probability and reduction depend on the quality and effectiveness of mask and its handling.

        • They protect the wearer by helping them not to inhale virions. Duh.

      • by dgatwood ( 11270 ) on Saturday November 21, 2020 @11:19AM (#60750916) Homepage Journal

        N95 masks protect both wearer and everyone around them. They're the best option.

        They all protect both the wearer and others. N95/KN95/R95/P95/P2/FFP2 masks are, of course, better in both respects, and N99/R99/P99/P3/FFP3 masks are better still.

        The important thing to understand is the math. A cloth mask with 20% filtration lets 80% of the particles through, but it also slows them down, so the reduction in spread should be significantly more than 20% because of a higher rate of falling out of suspension. But that is true only if it is being worn by the sick person, so for non-*95/*99-grade masks, it is extremely critical for the sick person to be wearing it, and much less effective for the non-sick person to be wearing it. Of course, asymptomatic spreaders mean that you can't know for sure whether you are sick or not, which means everybody has to wear them or else they aren't particularly effective.

        This is doubly true when you factor in the mask protesters. Because they don't wear masks (or, typically, do anything else) to protect themselves, they are statistically much more likely to get sick, and thus dramatically more likely to be the person spreading it (possibly asymptomatically). And because they aren't wearing masks, the asymmetric benefit of the sick person wearing the mask doesn't exist, so people with cloth masks are pretty much screwed. That's why mask laws are essential, and enforcement of those laws is essential.

        Either way, the reduction is proportional to the product of the complements of the percentage of filtration. An N95 mask that filters 95% lets through 5% (assuming a perfect seal), so two people wearing N95 masks (ignoring the asymmetric benefit of the sick person wearing one) means that .25% gets through. A cloth mask that filters 20% lets through 80%, which means that 64% of particles get through (again ignoring asymmetric benefits). This is why keeping your distance is also essential even with masks.

        • by grep -v '.*' * ( 780312 ) on Saturday November 21, 2020 @01:29PM (#60751206)

          means that .25% gets through. A cloth mask that filters 20% lets through 80%,

          I'm being pedantic here, but it's important.

          Two N95 masks with 95% filtration " means that 25% gets through." Lets 25% get thru?!? While a 20% cloth mask lets thru 80%? Why is the N95 so inefficient?

          NOT -- because there's a leading zero before that decimal point. So it's 0.25%, so the decimal stands out, so it's not mis-read. So PUT IT THERE. Otherwise it's easy to miss that decimal point and misread it and come to a wrong conclusion. (So says my 1975 physics teacher. And he's right. Leading 0's don't always mean octal.)

          • by dgatwood ( 11270 )

            Yeah, I usually include the leading zero (for exactly that reason). I'm not sure why I didn't this time. I guess I was typing too quickly and didn't edit as carefully as I usually do. Thanks for pointing that out. :-)

        • I think people are reading into this study incorrectly; the results of the study align with our vast understanding of virus transmission combined with what is evident among the populations under mask-wearing orders.

          First, remember the far, far more prominent transmission vector is through touching a surface with virus particles then touching your face. The virus usually ends up on a surface because a sick person (even the non-sick) is likely to be frequently coughing into their hands, rubbing their nos
          • by dgatwood ( 11270 )

            First, remember the far, far more prominent transmission vector is through touching a surface with virus particles then touching your face. The virus usually ends up on a surface because a sick person (even the non-sick) is likely to be frequently coughing into their hands, rubbing their nose or eyes, etc.

            Not true. Surface transmissibility depends heavily on what kind of virus you're talking about. Some viruses don't survive very long on surfaces at all. Others do. Some are more prone to airborne transmission than others because of the probability of causing virally loaded aerosols. And so on.

            Coronavirus generally does not cause sneezing, which is the primary mechanism of fomite transmission (via surfaces). So although surface transmission is possible it is generally considered to be very rare [thelancet.com].

            If you spend any time at all in a North American city with a mask mandate, you'll see the exact problem: they are only worn where required, taken on/off frequently, and done so in a highly improper fashion. People will pull their crumpled mask from their pocket just prior to entering a restaurant, shove it back in when sitting, then take it out to put on once more. The process of putting on/taking off a mask actually needs to be done very carefully - you are touching your face and thus dancing with the most likely transmission vector, in order to try and prevent a much smaller transmission risk. It seems logical thus, that studies would show little benefit to the wearer, but potential reduction in spreading, but most likely because it acts as a physical barrier preventing a sick person from (for example) coughing into their hand and spreading that virus onto a surface.

            That's

      • and are willing to take the time to ensure you have a proper seal. Also don't forget to shave clean. Hipsters need not apply.

        The reason we're not pushing N95 is because they're really only needed if you're going to be working with potentially infected people. If you're social distancing like you're supposed to and everybody wears them cloth masks work fine.

        Giving everybody n95s they're not going to wear properly though is probably counter productive though.
        • Giving everyone cloth masks they're not going to wear properly is similarly counterproductive.

          If

          a). you're going to push mask use or
          b). you're going to require it

          it's best to use the best available masks, which in this case happens to be N95/KN95 masks. The kind without the valves + filters.

    • by Jerry Atrick ( 2461566 ) on Saturday November 21, 2020 @10:46AM (#60750814)

      True but the only way many selfish deniers will be coaxed into using them is showing they also help the wearer.

      • by gweihir ( 88907 ) on Saturday November 21, 2020 @10:54AM (#60750834)

        Nothing will convince the deniers. That is their very nature. These people are not rational.

    • Why is testing to see if masks protect the wearer "wrong"? This seems like a reasonable thing to science. This stigma on negative results is exactly why file drawer bias exists. The fact that they used participants' self-reported results doesn't mean they did it "wrong". It just means you, the reader, need to consider this context when interpreting the results. Heck, the nature of the analysis of such things means that one will never find evidence that mask usage is not helpful anyway. You may simply
    • It is to protect everybody else _from_ the wearer, which wasn't tested in this flawed test.

      Correct, especially when most cases are spread by people with no symptoms [cnn.com], according to the CDC.

      "CDC and others estimate that more than 50% of all infections are transmitted from people who are not exhibiting symptoms," it added in the guidance posted Friday.

      "This means at least half of new infections come from people likely unaware they are infectious to others."

    • Re: (Score:3, Insightful)

      by dumbdumber ( 7475818 )
      You are dead on concerning what the study did, how does that make it flawed ? The study apparently came to the conclusion that the mask does not protect the wearer. That's all it claimed! Further, is it better to use the "body of evidence" than actual science to further human knowledge ?
    • They didn't even test whether wearing a mask would reduce the spread to others.

      They tested whether *recommending* that someone wear a mask reduces their chance of catching. That's what they measured poorly.

      I hereby recommend that everyone reading this go to law school.

      I think if we look back four years from now we'll find that my*recommending* that you go to law school did not increase your chances of becoming a lawyer. Actually going to law school GREATLY increases the chances.

      Same here - recommending th

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      Studies that confirm my beliefs are solid science and incontrovertible.

      Studies that cast doubt on my beliefs are flawed and testing the wrong thing. The scientists behind them are biased and racist.

    • by hey! ( 33014 )

      It shouldn't be surprising that the evidence for masks protecting the wearer is more mixed than the evidence for masks protecting others. Look at the way people mishandle their masks -- wearing them below the nose, tugging them up and down by the front instead of the sides, touching their face and running their fingers around the mask's edge.

      There's plenty of engineering style studies suggesting that multi-layer cloth masks can block virus droplets, but not as effectively as N95. But take a mask that is

      • It shouldn't be surprising that the evidence for masks protecting the wearer is more mixed than the evidence for masks protecting others. Look at the way people mishandle their masks -- wearing them below the nose, tugging them up and down by the front instead of the sides, touching their face and running their fingers around the mask's edge.

        It's all some pretty basic physics. Gravity and acceleration and deceleration. Small particles that hitch a ride on larger ones, and what happens when the larger ones deteriorate or get stuck on the inside or outside of a mask.

        I think the resistance is based on the alarming practice of some people getting their science education from politicians.

    • by Octorian ( 14086 )

      It tested the wrong thing, but it wasn't that.
      It tested if recommending that people wear masks, in a community where mask wearing is uncommon, affects infection rates.
      In other words, it was testing the effects of a limited PR campaign. Not the effects of actual mask wearing itself.

    • What a shameful perspective from both the media and your post on this study. How is it not clear to you that this whole thing isn't entirely political anymore? Of course the study has limitations to it - as with any proper study they point those out themselves as part of the study. Read the headlines of all media articles on this study, even this Slashdot story: "Despite one flawed study in Denmark"??? The fact the study has limitations is obvious, and every study including the one that demonstrate when
  • by sarren1901 ( 5415506 ) on Saturday November 21, 2020 @10:41AM (#60750808)

    I'm fairly prone to catch every little cold or flu that goes around. One of the pitfalls to going to concerts and working in a busy public area. After catching this stupid virus in February I have yet to catch anything else. People in my building have gotten corona and the boss and assistant had the flu but so far I've not had anything.

    While this is only my personal experience it definitely seems to be helping. I don't know if it's the mask itself but just seeing the mask reminds people to keep more distance then normal. I've also haven't seen anyone really coughing up a storm or otherwise plague spreading where as before this pandemic, it was a daily affair.

    I'm gonna chalk this up to the masks and social distancing. It's really nice not catching a cold or flu every other month.

    • by gweihir ( 88907 )

      I still had the occasional cold, despite N95, hand disinfection and mostly staying at home. But it has gotten noticeably less and that is nice.

    • Start getting enough Vitamins B6, C, D, E, and K plus supplemental zinc. There's been several studies that show the lack of Vitamin D makes a person more vulnerable to the common cold, influenza, seasonal affective disorder and now possibly COVID-19. In fact, Harvard Health posted an article about this issue way back in 2008 about the lack of "natural" Vitamin D between fall and spring if you live north of 37 North latitude:

      https://www.health.harvard.edu... [harvard.edu]

      • Start getting enough Vitamins B6, C, D, E, and K plus supplemental zinc. There's been several studies that show the lack of Vitamin D makes a person more vulnerable to the common cold, influenza, seasonal affective disorder and now possibly COVID-19.

        I would add, to our fellow folks with dark pigmentation that live in more northerly latitudes, that Vitamin D is more difficult to manuafcture due to the darker skin color. So make certain you get enough supplements https://www.msn.com/en-us/heal... [msn.com]

    • When did this bit of science fiction - that viruses easily transmit through aerosols (floating around in the air) - become an assumed fact here? I thought people here listen to science and logic. Of course it can happen, but we've lost all semblance of risk-weighting and informed response. (Droplets or course, are a higher risk. Still low, but no longer negligible; thus in a hospital the only times you'll see anyone wear a mask is when leaning over a sick patient or performing surgery - SCIENCE!)

      It i
      • One infected person sits in a coffee shop in Korea under an air conditioner. Everyone in the coffee shop catches SARS COV-2 (except the four masked employees). But viral transmission via aerosols is science fiction. Sure, bub.

    • .

      I'm gonna chalk this up to the masks and social distancing. It's really nice not catching a cold or flu every other month.

      You aren't the only one noticing this.

      A takeaway is that the physics is sound. Previous to the great mask wearing, people were exchanging flegm droplets and snot.

    • by antdude ( 79039 )

      My colony and I easily get infected to be sick like the annual flu. So far, we got no virus infection this year. :)

  • A germaphobe was unusual. In less than 1 year of MSM fear mongering, germaphobia is becoming the norm. I for one refuse to see my fellow human beings as a bio-hazard.
    • by gweihir ( 88907 ) on Saturday November 21, 2020 @10:56AM (#60750846)

      A germaphobe was unusual.
      In less than 1 year of MSM fear mongering, germaphobia is becoming the norm.
      I for one refuse to see my fellow human beings as a bio-hazard.

      There is always somebody both stupid and proud of it. Found them.
      As a result of your stance, others should very much consider _you_ a bio-hazard though.

    • Me too, but a little different:

      They do not carry the hazard. They *are* the hazard. ;)

      Just have to take a peek at the big poster of known species in my area from a few decades ago. And the almost empty big white poster of speices still found today.

    • Re: (Score:2, Insightful)

      by quantaman ( 517394 )

      A germaphobe was unusual.
      In less than 1 year of MSM fear mongering, germaphobia is becoming the norm.
      I for one refuse to see my fellow human beings as a bio-hazard.

      I, for one, hope I don't get too close to you and inadvertently kill my mother.

    • Do you not believe that viruses can be transmitted, do you not believe in asymptomatic carriers, or do you simply believe you are immune?

  • by Vihai ( 668734 ) on Saturday November 21, 2020 @10:56AM (#60750850) Homepage

    If the masks were much more effective than that in preventing an infection in a real setup the effect would be epidemiologicaly more evident. I'm talking about the overall probability of infection which considers the average misuse/mishandling of the mask.

    Who expects a mask to greatly reduce probability of infection is deluded, as much as who says that it is ineffective or harmful.

    That said, even a reduction of 14% is significant and may have a strong effect on the replication number.

    • Seconded. I'll take that 14% resist buff.
      Especially since I'm only wearing it when it makes rational sense. Which is a bit of burden still, but not worse than 14%.

      (I'm vastly more competent at mask handling than the average clueless person though. It's what you get, for growing up with a microbiologist parent. I manage to keep complete touch separation between my zone and the contaminated outside zone almost everywhere. My hallway almost has an airlock. I never touch my mask with "outside" fingers and then

    • by quonset ( 4839537 ) on Saturday November 21, 2020 @11:57AM (#60750986)

      If the masks were much more effective than that in preventing an infection in a real setup the effect would be epidemiologicaly more evident.

      I'll provide the facts, but you'll find some excuse to ignore it or for why its' wrong.

      From Kansas [wibw.com]:

      “Some counties have been the controlled group with no masks and some have been experimental group with masks are worn and the experimental group is winning the battle. All of the improvement in the case development comes from those counties wearing masks,”

      From Alabama [nbcnews.com]:

      In Alabama, Gov. Kay Ivey announced a statewide mandatory mask order on July 16. Since then, the state saw a significant drop in daily Covid-19 cases, with numbers peaking above 2,000 toward the end of July and hovering over a 1,000 a month later. And now, cases have plummeted to 574 a day.

      “The mask absolutely played a very important role and we really have had no other significant limitations or interventions other than the mask,” Dr. Scott Harris, state health officer at the Alabama Department of Public Health, told NBC News this week.

      From South Carolina:

      South Carolina has no statewide mask requirements, leaving 11 jurisdictions with mask mandates and 61 without. The South Carolina Department of Health and Environmental Control’s latest findings, from mid-August, report that communities with mask mandates saw a drop of 34 cases per 100,000 people for the four weeks after the requirements were implemented, compared to before the orders took effect. In the same period, jurisdictions without mask requirements saw a rise of 24 cases per 100,000 people.

      "Our South Carolina mask analysis data shows us what we already knew, wearing face masks works,” Dr. Linda Bell, an epidemiologist at the South Carolina health department, told NBC News in an email.

      From Ohio [cleveland.com]:

      DeWine during his coronavirus briefing on Thursday said mask orders, some of which were first issued locally, have made a difference. In Franklin County, for example, DeWine said, “When the use of masks went up dramatically where you were getting 90% or so, we started seeing a slow down.”

      Back in May [forbes.com] it was predicted that wearing a mask could reduce infections by up to 80% and used the comparison between Japan, which never locked down, and the U.S.

      On March 6 in Japan, a country of 126 million, 21 people died of COVID-19. On the same day, 2,129 people died in the US - over 10 times the deaths in Japan. (The US population is only 2.6 times greater by comparison). While America begins reopening, Japan never closed. As I write these words, Japan shows no new cases, with only 624 deaths. Today, the US added 14,325 cases, despite tweets from the White House that nationwide numbers are declining. The USA continues to lead the world: 781 new deaths today bring the total US number to 81,568, according to the Worldometer coronavirus website.
      . . .
      The reason, DeKai points out, is that nearly everyone there is wearing a mask.

      But please, tell us how none of this points to the overwhelming fact masks are effective at slowing and preventing infections.

      • by Vihai ( 668734 )

        Yours is a straw man. I said that that effects would be more evident. Never said they are not effective at all.

        Given that R0 of Covid-19 is estimated to be between 2 and 4 if masks were actually 80% effective you wouldn't have had any spreading of the virus at all in countries like Japan where masks are culturally worn by most people. However in Japan they are experiencing their third wave meaning that masks can not be so much effective in real setups.

        • Thank you for proving my point about ignoring the facts. If you don't call going from over 2,000 cases per day to less than 600 in one month, nothing will convince you. Keep up the disinformation fight as the U.S. is seeing 2,000 dead per day as people stopped wearing masks.

          Oddly, those states who refused to introduce mask polices are now seeing record cases and deaths in their states and hospitals are now at or near ICU capacity. Such as in Utah [utah.gov] where it is stated:

          Universal Masking Can Avert Disaster.

          This dire result can be avoided or lessened dramatically if Utahns wear masks, socially distance whenever they around others, avoid social gatherings, and take other hygienic measures. Otherwise, Utah could replay the tragedies we saw in Italy, New York and other areas last spring when hospitals were completely inundated with COVID-19 patients.

          Wisconsin has 2/3 of all hospitals at [wwltv.com]

      • Re: (Score:3, Insightful)

        by carton ( 105671 )

        Kansas: confounded by urban vs. rural. No metric is cited, just a "public health official" saying the maskers are "winning." You would never accept this standard of testimony if it were coming from orange man.

        Alabama: Have a look at the graph of New York City at peak and one month after peak. Measurements confounded by time should be dismissed out-of-hand. You at least need to control against a similar state that made no change. In addition, I presume the comparison was counfounded by all sorts of othe

      • I read the first two sources, and neither says what you think they do. They do not provide a strong case for mask use at all - at the least, there's no way you can label their effects "overwhelming fact" with intellectual honesty if you did in fact read your sources. The first is kind of laughable - you need to understand the person in these types of articles is a county bureaucrat trying to justify a mask order. I'm not saying their wrong, but he has clearly cherry picked data to support his argument.
    • This is a hard part of the entire argument for many to understand, and I would have hoped it was not so controversial to an audience of largely "entire system" thinkers like engineers and programmers.

      Let's assume for a minute we had countless studies showing masks to be highly effective (leave it to reader to go research what studies actually say about masks): it is hard for most people to understand you can agree with that and still argue that mask-wearing policies are actually harmful, or at best negli
  • Which masks!?
    (Percent of what!?)

    I have no doubt that proper medical masks, worn under the conditions they were tested for, work well.

    I also have no doubt, that some random piece of cloth, coarse enough to not stop much, yet badly designed enough to vent aerosols at the top, don't work at all.

    Guess which one the average wearer out there wears...
    Until soaked and being rubbed agains his hands, mind you.

    Proper masks for everyone!
    What do we have governments for, if not for that??
    Hell, I'll work at that factory

  • This is an interesting case study on "what happens when your data and results don't line up with the conclusions you want."

    What can you do? You can blame the subjects (they didn't do what they were supposed to), the testing environment (no virus was around), or the design (the methods were not sound).

    The fact is, this particular study it showed masks weren't effective. And it was double-blind.

    So what? It shows science does not exist in a vacuum. People who say we should believe "science" are naive; this par

    • by Vihai ( 668734 )

      The fact is that this study shows masks are as effective as expected.

      The problem lies in who expected a way bigger effect.

      That said 14% of reduction in probability is significant and has a significant effect on the infection curve... for a device that is so cheap.

  • Comment (Score:1, Insightful)

    by Spudboy2003 ( 717547 )
    Shut up and do as you are told slaves.
  • There is no undeniable truth outside of mathematics and religion.

  • by amorsen ( 7485 ) <benny+slashdot@amorsen.dk> on Saturday November 21, 2020 @11:38AM (#60750950)

    I made a study, and masks turn out to only be 14% effective at stopping tiger attacks. Yet the health authorities keep recommending masks!

  • I have worked with microparticles that hung in the air for 24 hours or more for years (building and construction). Unless your mask has a perfect seal around your nostrils and mouth with a filter that works on very small scales, it will not work against COVID-19 given how long it seems to remain airborne. The longer something stays airborne the smaller it is, and the tighter the seal needs to be. Had I worn the "surgeon"-style mask I would have been dead by now as it would not provide a good enough seal for

    • Dose makes the poison, one viral particle can be enough ... but it doesn't need to be.

      Shame hat it's hard to put surgical masks on ferrets, they are the only decent model we have for experiments.

    • Most COVID19 transmission happens in small particles of spit. It's not free-floating virus diffuse in the air, it's spit particles that drop relatively quickly.
  • by bb_matt ( 5705262 ) on Saturday November 21, 2020 @11:50AM (#60750982)

    Some wear masks and consider them a shield against getting the virus, rather than some protection from *spreading* it.
    You can get N95 respirator masks if you can find them and assuming you don't get ripped off these days, which is about the best you can get.

    All too often, you'll see the same people with the mask not covering the nose, halfway down the chin, constantly fiddling with it by touching and pulling the area around the nose and mouth. Sure, you can adjust it, just be careful and tug it gently from the bottom of the mask! So frikkin' obvious.

    The vast majority of cheap masks - even a damn t-shirt folders over twice - what they'll do is simply stop the distance that droplets spread when someone talks, coughs or just breathes - and that's *good* - it cuts the risk. Even if it cuts it by 10 to 15 percent, it's better than nothing.

    But masks like these are clearly not going to protect you in the unfortunate event that you happen to walk unwittingly into a pretty much invisible cloud of covid-19 infected droplets.

    That's rare, unless you in the habit of frequenting heavily crowded places with high infection rates and poor ventilation - then your luck diminishes, obviously.

    Then we get people who just use the same mask again and again without washing it - probably more at risk of getting skin condition than anything else, but it will also increase the risk of getting covid-19 if there's droplets that made it onto the surface mask but didn't penetrate any further.
    Scrumple that mask up in your pocket, touching the surface with the virus on it ... and yeah, you'll be unwittingly increasing risk.

    I think everyone should watch those videos where they demonstrate how a powder invisible except with infra-red light, spreads amongst a group of people.
    It is alarming. From a single source, within a small period of time, when the infra-red light is turned on, the stuff is *everywhere* - people's faces, door handles, light switches. It should be a wakeup call.

    If you think about how easy it is to actually get the virus if you are unlucky - heck, an infected person goes into a rest room, coughs whilst washing hands, leaves. You enter seconds later - bang - there's a good chance you've now got it, simply be being in the wrong place at the wrong time...

    • Your conclusion on risk is very wrong and I think I see why - you misunderstood a key term in the multitude of studies on this subject. The only viable airborne transmission vector for viruses (and studies show COVID-19 is no different) is indeed through droplets, but there is actually a specific meaning to this word and it is very different from your subsequent example, which speaks to aerosols. This is in fact a common error from people who think they've seen incontrovertible evidence that masks are eff
  • can be quite large. Is it plausible that wearing a mask protects you? Of course. Is it therefor true that wearing a cut-up t shirt around your face is a valid strategy to avoid severe covid?

    As opposed to wearing a surgical mask or an n95?

    When the masks are handled and removed and adjusted and reused for days on end?

    When a lot of the time people have their nose wide open over the mask?

    When, as everyone rightly predicted back in February and March, that a certain segment of the population will assume that
  • There's no doubt that N95 masks work to protect the wearer and others. The real questions are:

    - Do the types of masks that regular people wear work either as well as N95 masks or at all?

    The only randomised control trial I've seen warns against using the cloth masks. Quote:
    "This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may re

  • I thought the "95" in "N95" meant 'only 95%'.

    I thought coronavirus virions were smaller than the holes/porosity of even N95 masks and therefore could not stop everything.

    I thought we could catch this infection through our eyeballs, making the mask debates nearly pointless.

    I thought that, although the virions are transmitted a shorter distance when wearing a generic cloth mask, they are still transmitted, meaning anyone who inhales the same air within hours is at risk.

    My point, and what I consider t
    • The individual virions may be that small, but you're unlikely to see them floating through the air without being suspended in material ranging from moist droplets to mostly dehydrated aggregates of saliva proteins, hence the intention of the surgical masks to catch some portion of the the droplets before they have a chance to dehydrate. Reducing the velocity at which they are expelled also likely lessens the potential for them to hang in the air for long periods of time. Imperfect, but better than nothing -
      • It's not an immediate license to go out and do whatever the hell they want. It can cut down on the infection rate and spread that in a month or so people (still masked) could do anything, because the rate in the community would be so low.

        • (meanwhile in some alternate reality where people don't suck)

          People need to get it through their skulls that "personal responsibility" doesn't end at their arms' reach, or even the room they currently occupy.
  • by ceoyoyo ( 59147 )

    FFS, right in their abstract: "the 95% CIs are compatible with a 46% reduction to a 23% increase in infection." That's IF there were no issues with compliance, loss to followup, or any of the other things they identify, *in the abstract* as serious limitations.

    In other words, the results did not indicate "that the medical masks issued were not particularly effective," they indicated that the study was essentially uninformative.

    Not reading TFA, or even TFS, isn't just a Slashdot phenomenon.

  • Time to stop the lockdowns and social distancing, masks are the fix.
    • by marcle ( 1575627 )

      Nope, the masks aren't 100% effective. You have to social distance too, and if the pandemic is raging (like it is right now) then lockdown can be necessary too.

    • Long term masks, plus a month of an actual lockdown, would probably be the fix, yes. Once we cut down on the number of cases in the community, we can do a lot with just masks.

  • by hey! ( 33014 ) on Saturday November 21, 2020 @01:05PM (#60751152) Homepage Journal

    I'd call the Danish paper "limited", which is true of any scientific paper. It doesn't have the probative power to support the kinds of conclusions people started draw from it, and to attack those excessive inferences others started trotting out the adjective "flawed", which describes almost every scientific paper.

    People need to understand that in any complex real-world problem a single paper almost never never resolves anything. It's nearly always possible to cherry pick evidence that supports any position you care to take. This doesn't make every opinion equal; opinions that fit the *totality of available evidence* are better informed.

  • A lot of other tests, other than the denmark one, prove it to be NOT effective.. Even a consumer products test program proved that regular masks (not the medical ones, which are NOT being sold in supermarkets etc) are almost useless.. Also countries where they are forced to wear a mask have the same spikes as countries where masks aren't forced, so it jus shows that masks really don't add much to the protection (and because most people even wear them multiple times and wrong, they might even have the oppos
  • for a proper study you need a control group who are wearing masks with great big holes and are ineffective, the "placebo mask"

  • It should be intuitively obvious that masks protect both the wearer and others. Right now, data is lacking to know just how effective either of those is, and to what extent it helps limit spread in view of many other factors, such as frequency of gatherings, cultural habits such as hugging or hand-shaking, etc.

    It's a fight just for fighting, until there is more data. By the time there is enough data, the issue will be moot.

    Just don't think that a mask is your silver bullet, nor that it's useless.

Keep up the good work! But please don't ask me to help.

Working...