Catch up on stories from the past week (and beyond) at the Slashdot story archive

 



Forgot your password?
typodupeerror
×
Medicine

Face Masks Offer More Protection from Coronavirus Than Many Think (latimes.com) 356

Face masks "offer much more protection against coronavirus than many think," reports the Los Angeles Times. [Alternate version here ....] There's a common refrain that masks don't protect you; they protect other people from your own germs, which is especially important to keep unknowingly infected people from spreading the coronavirus. But now, there's mounting evidence that masks also protect you.

If you're unlucky enough to encounter an infectious person, wearing any kind of face covering will reduce the amount of virus that your body will take in. As it turns out, that's pretty important. Breathing in a small amount of virus may lead to no disease or far more mild infection. But inhaling a huge volume of virus particles can result in serious disease or death. That's the argument Dr. Monica Gandhi, UC San Francisco professor of medicine and medical director of the HIV Clinic at Zuckerberg San Francisco General Hospital, is making about why — if you do become infected with the virus — masking can still protect you from more severe disease...

She cited an outbreak at a seafood plant in Oregon where employees were given masks, and 95% of those who were infected were asymptomatic.... The protective effects are also seen in countries where masks are universally accepted for years, such as Taiwan, Thailand, South Korea and Singapore. "They have all seen cases as they opened ... but not deaths," Gandhi said.

"The emerging scientific data is clear: wearing a mask doesn't only protect others, it also significantly reduces your own risk of getting Coronavirus," one U.S. governor recently pointed out.

"So if you're a selfish bastard and wearing a mask to protect others isn't enough of a reason to do so, then maybe protecting yourself is?"
This discussion has been archived. No new comments can be posted.

Face Masks Offer More Protection from Coronavirus Than Many Think

Comments Filter:
  • by Futurepower(R) ( 558542 ) on Saturday July 18, 2020 @10:38AM (#60303915) Homepage
    The human immune system may be able to protect itself if a smaller amount of virus is introduced.

    So, if a mask only removes some of the virus, it can be effective.
    • by makomk ( 752139 )

      The problem here, I think, is the scale at which this effect works. Like, if you look at the flu study [nih.gov] referenced in the article, they step up the dose in power of ten steps and still get meaningful results, because that's roughly on the order of what was needed to get a substantial change in either the number of people infected or showing symptoms. Your typical fabric mask is maybe on the order of a 20-50% reduction if I remember rightly, probably closer to 20% if the person wearing it is the uninfected on

      • by raymorris ( 2726007 ) on Saturday July 18, 2020 @11:40AM (#60304147) Journal

        The key thing to understand about an infectious disease that the general media doesn't cover much is the basic reproduction rate, abbreviated R.

        Suppose that for every hundred people who are infected today, they pass it along to 110 new people. The number of new cases would rise exponentially every couple of weeks:
        100 cases
        110 cases
        121 cases
        133 cases ...

        That's called R 1.1

        Conversely, consider if 100 people infected today pass it along to 90 people, and R of 0.9:

        100 cases
        90 cases
        81cases
        73
        66 ...
        0 cases

        Right now the R is pretty close to 1.0, which ia reflected by the fact that the rate of new cases isn't changing much. (Depending on location)

        Keep that in mind, let's go back yo what you said:

        > Your typical fabric mask is maybe on the order of a 20-50% reduction if I remember rightly, probably closer to 20% if the person wearing it is the uninfected one. That's not much good.

        Just for fun let's use a number on the low side, only 25%.
        What happens if we reduce the transmission rate by 25%.
        If we start at 1.0 and reeuce that by 25% to 0.75, that means the case rate each round is 75% of what it was in the previous round:

        100 new cases
        75 new cases
        56
        42
        32
        24 cases
        18 cases

        A combination of measures that reduces the transmission rate by 20% or 30% or whatever is how you get R below 1.0 and thereby get case rates to about zero. That's how we can eridicate the virus - by reducing the transmission rate by 20% or 30%.

        > probably closer to 20% if the person wearing it is the uninfected one.

        One recent study found 65%, but let's go with 20%.
        The key thing is that's 20% PER ROUND. If your high school wears a mask today, he's 20% less likely to catch it. Which means he's 20% less likely to pass it to the bank teller, multiplied by the bank teller is 20% less likely to catch it EVEN if the football coach has it, so the bank teller is 36% less likely to catch it. That means the teller is 36% less likely to be able to pass it to your brother. Since your brother is wearing a mask, he's 49% less likely to catch it, meaning less likely to pass it to you.

        A 20%-50% reduction in the likelihood of getting the virus THIS WEEK leads to a 99% reduction in the risk of catching it a few months from now. Simply because the person you were going to catch it from never got it, because they were wearing a mask two weeks before you met them.

        • by msauve ( 701917 )
          The GP was talking about the reduction of virus particles (virions) being spread. You're using that number as if it were the change in infection rate. It's not.

          More specifically, he claimed that the study used a 10x factor in virions to get a meaningful change in infection rate, so a 1.25x factor (25% increase) should make little, if any, meaningful change in the infection rate.

          I don't know if his numbers are right, just sayin'.
          • by msauve ( 701917 )
            Math was a bit wonky. Let me try again. Study used 10:1 ratios, i.e. a 90% reduction of virions to get a meaningful change in infection rate. A mask which filters 25% is much less of a change than what the study found was needed to make a meaningful difference.
        • by raymorris ( 2726007 ) on Saturday July 18, 2020 @12:03PM (#60304261) Journal

          Having explained it, let me summarize the bottom line in two sentences:

          If case rates keep rising 10% per month, it's almost guaranteed that you and your family will get covid.

          If case rates drop 10% per month, you are your family probably won't get it.

          How important is it for rates drop (even a little bit) rather than rise?

      • by dgatwood ( 11270 ) on Saturday July 18, 2020 @11:42AM (#60304167) Homepage Journal

        Your typical fabric mask is maybe on the order of a 20-50% reduction if I remember rightly, probably closer to 20% if the person wearing it is the uninfected one.

        Indeed. I've heard 30%, but either way, that demonstrates pretty clearly why making everyone wear masks is so critical. The only way masks really help enough to matter is if the infected person is wearing the mask, and if you can't know that you're infected with any degree of certainty, then the only way to ensure that is to mandate mask wearing for everyone, with no exceptions.

        I'm not convinced, based on the information in the article, that this is going to be any more effective at reducing severity of symptoms than it is at reducing spread either - there just doesn't seem to be evidence supporting this.

        Take a look at this analysis [nih.gov] of the 1918 flu. Basically, their conclusion was that exposure to a severe case made people more likely to get a severe case, largely because of higher levels of viral particle exposure.

        That neatly explains why deaths tend to be heavier near the start of each wave. The more quickly you bring the replication numbers down, and the more you do to limit exposure to people who are shedding lots of virus particles, the fewer people will get severe symptoms. Individually, it may not matter much, but in aggregate, the difference between exposing 3 people to a large viral load and exposing 1.4 people to a medium or small viral load can really add up to a big difference in deaths, particularly given that those smaller viral loads are less likely to cause the next person to die, and so on.

        That also explains why dense cities had far more deaths than less dense areas. Compare NYC to the SF Bay Area, for example. NYC has seen only 10% more cases than the Bay Area, but had more than four times as many deaths.

      • Re: (Score:3, Insightful)

        by Aighearach ( 97333 )

        Wave your hands and point at unrelated research, or just put on the fucking mask, asshole?

      • According to that reasoning, an N95 mask would barely have any effect either since at 95% efficacy, it gives just over one order of magnitude reduction.

        When the performance of respirator masks is discussed, it's usually about how well they can filter particles that are 300 nm in size, because those are the hardest ones to block (This is about the particle size of cigarette smoke, by the way.) But Covid-19 is thought to spread mostly by much larger droplets (> 5 micrometer), for which low-tech masks are s

  • Face masks (Score:5, Insightful)

    by fluffernutter ( 1411889 ) on Saturday July 18, 2020 @10:38AM (#60303919)
    If face masks didn't work, every country would have a curve as large as the US.
    • If face masks didn't work,

      That was not the claim. The claim was that they offered little protection to the wearer.

      every country would have a curve as large as the US.

      That is false. Even if face masks didn't work, those countries making other meaningful responses to Covid like track and trace might still be doing better than the US. Here in the US we are doing half-assed mask wearing, half-assed shelter in place, etc etc. We are half-assing the entire response.

      • by ghoul ( 157158 )

        You cant really expect better when half of the American population are ASSES. Thats what happens when you dont allow parents to whoop their kids and teachers have to treat dumbos the same as smart kids. People grow up dumb and think their opinion matters. Dumb people exist everywhere but in other cultures the dumb folks know enough to listen to their intellectual betters but American culture of participation prizes makes idiots think their opinion matters instead of just listening to smarter folks.

  • by SuperKendall ( 25149 ) on Saturday July 18, 2020 @10:43AM (#60303927)

    People everywhere seem to talk like catching a virus is a binary thing.

    But it's not the case at all, any reduction you can have in exposure is helpful. Viral load is a huge component as to how sick you will get, to your body being overwhelmed by the virus or not.

    That means that masks do help - not even just from filtration, but also from preventing you getting contamination you have have on your hands onto your mouth.

    That also means that what you should be concerned about is the duration of exposure to other people. Outside walking around, never next to someone for more than a moment? No risk. Inside wandering around, never close to any one person for long (like a grocery store) - low risk, as long as you wash your hands and don't touch your face.

    Inside next to people for a while is then obviously the highest risk, and even outdoors for a while next to the same people all the time carries some risk (though much lower as natural air currents will quickly disperse anything).

    This is also why the world is probably a lot better off than it would seem, way more people have had low level exposure and already developed some resistance. The death rate continues to fall generally [worldometers.info] (though there's been a slight uptick recently) even as the infection rate soars... that infection rate is measuring a lot of people who have had low level exposure mow, have developed a resistance and are not going to get all that sick.

  • Comment removed (Score:5, Insightful)

    by account_deleted ( 4530225 ) on Saturday July 18, 2020 @10:46AM (#60303937)
    Comment removed based on user account deletion
    • by klipclop ( 6724090 ) on Saturday July 18, 2020 @10:59AM (#60303985)
      I think you have to be a selfish bastard going out and trying to do normal crowded recreational things in a pandemic. Mask or no mask.
    • Illinois Assembly Speaker Michael Madigan, is not only a selfish bastard for giving nuclear powerplant operator Exelon and provider of zero-carbon electricity 150 million in rate increases in exchange of offering a paltry 1 million in contracts and jobs to persons in his South Side Chicago district of minorities and other underrepresented persons, he is seen in this picture wearing the type of construction-site face mask with a valve.

      Whereas significant gains are made every day by wind and solar power, t

  • by fredrated ( 639554 ) on Saturday July 18, 2020 @10:49AM (#60303951) Journal

    as much as it is being forced to stop at a red light. The horror!

    • by SkonkersBeDonkers ( 6780818 ) on Saturday July 18, 2020 @11:10AM (#60304021)

      the really "funny" ones are the claims that mask mandates are unconstitutional and unenforceable

      just as the most obvious example, almost everywhere in the USA prohibits public nudity and those laws exist for no reason other than most people don't care to see naked folks wandering around and no one would dream of suggesting the laws are unconstitutional and unenforceable

      so yes, with valid public health concerns, even if it is only a partial "solution", mask mandates are absolutely constitutional and enforceable and since they are entirely temporary and non-invasive you can't even attempt to make the arguments that anti-vaccination folks do

    • I think we should be wearing masks, and it's stupid not to. But comparing to a red light is stupid. You have to stop at a red light because the roads were paid for by the government. If you want to use the roads, you have to abide by the rules the government set for using the roads, including stopping at red lights.

      The government didn't pay for the air we breathe. So normally it has no power to force you to wear a mask. The only reason it can do so right now is due to a public health emergency. The peop
    • If wearing face masks meant you end up getting laid then people would be wearing them like condoms, they'd always have a couple of them in their pocket, a drawer full of them at home, and they'd be bragging about size, flavours and the perfect fit.

    • Ebil gubermint is mandating pants! Don't let the Gubermint take away yer freedums, refuse to wear pants!

  • Is if it is discovered that all the lockdowns and restrictions were actually pointless, all we had to do was wear masks starting in March and everything would have been OK.
    • Not only would have the WHO&co lies have helped destroyed their credibility, it would also have needlessly increased how long this mess takes.

      That was one great little white lie ...

    • by DogDude ( 805747 ) on Saturday July 18, 2020 @11:00AM (#60303995)
      The lockdowns were supposed to allow the governments time to organize and get their shit together, which every country did, except for the US.
      • We got our shit together in Oregon, we have mandatory mask policy even outdoors whenever within 6' of another person.

        Our only problem is young people are still holding house parties. The government isn't supposed to stop that; that's the People's fault only.

        In Oregon, individual risk remains low, ICU beds are not forecast to run out, and the government is responding to events on a daily basis, including adding new restrictions when the People fail to contain the spread.

        And the US federal government doesn't

    • Hey dumb ass, the point of the lockdowns was that we didn't know what was effective yet.

      Of course in that situation, if you had known what to do specifically, you wouldn't have had to do the generalized thing.

      Your comment is too stupid even for slashdot. Pull yourself together.

    • No. That's most certainly not going to be discovered. The combination of everything is what can fight the virus. Social distancing where possible. Where not, because you do need to get groceries, wear the mask.

      Europe got some really good results from that combo tactics.

  • Observe the urine studies [moonofalabama.org] and see for yourself

  • by Pinky's Brain ( 1158667 ) on Saturday July 18, 2020 @10:58AM (#60303983)

    If you can keep most infections asymptomatic, suddenly going for herd immunity is a much less daunting experiment.

    • by ttfkam ( 37064 ) on Saturday July 18, 2020 @11:22AM (#60304067) Homepage Journal

      Herd immunity for a novel (no pre-existing immunity in the population) virus that's highly infectious would likely require >90% of folks to have been infected. (Almost 300 million out of 330+ million people in the US alone.)

      There's a reason we aim for >90% vaccination rates for measles and polio. 50% wont cut it, and we're not even at the 10% mark yet for coronavirus.

    • If herd immunity was something we could rely on happening "naturally" then nobody would get chicken pox or polio or measles or any of the other diseases which used to be widespread. Vaccines are how we get herd immunity, end of story.
      • Pandemic flu's on the other hand exhaust themselves every year away from the equator. Also mumps was so dangerous precisely because it fluctuated between herd immunity and epidemic. Herd immunity works for a lot of viruses at least temporarily, and the herd immunity threshold varies.

    • by sjames ( 1099 )

      Tell you what, you go to the nearest hospital and get the COVID patients to sneeze in your face. Then report back how it goes.

    • If you can keep most infections asymptomatic, suddenly going for herd immunity is a much less daunting experiment.

      No. Look at the percent of the population affected so far.

      You would fill up the ICU, and the total deaths caused by the crisis would be double (or more) the number caused by COVID directly.

      You need at least 70% to have been affected to even get partial herd immunity, we'd have to have full-sized waves of the virus a couple times a year for a decade to get there.

  • The CDC, the WHO, and others really dropped the ball on this one. They first claimed that masks didn't work at all. That seemed to be for two separate reasons. First, the medical establishment is in general pretty conservative about accepting things and what counts as evidence. That's in part in response to a general problem where there are a lot of pseudoscientific proposals, so the default is to assume that something doesn't work without evidence, even if there's strong common sense, logical reasons. The

    • by ttfkam ( 37064 ) on Saturday July 18, 2020 @11:24AM (#60304081) Homepage Journal

      No, they said people shouldn't try to hoard N95 masks because folks working in hospitals and with vulnerable populations like in nursing homes should get priority.

      They never claimed masks didn't work. Go back and read their statements for yourself instead of reading Breitbart's opinion on it.

      • The phrasings if you look at them were ere at best imprecise to the point where it didn't make a difference. For example, from https://www.cdc.gov/media/releases/2020/t0212-cdc-telebriefing-transcript.html [cdc.gov], from February:

        At this time, some partners are reporting higher than usual demand for select N95 respirators and face masks. CDC does not currently recommend the use of face masks for the general public. This virus is not spreading in the community. If you are sick or a patient under investigation and not hospitalized, CDC recommends wearing a face mask when around other people and before entering a health care provider’s office, but when you are alone, in your home, you do not need to wear a mask. People who are in close contact with someone with novel coronavirus, for example, household contacts and care givers of people with known or suspected 2019, I’m sorry, nCoV 2019, we should wear a face mask if they are in the same room as the patient and that patient is not able to wear a face mask.

        Or look here https://www.cidrap.umn.edu/news-perspective/2020/04/commentary-masks-all-covid-19-not-based-sound-data [umn.edu] where masks for general use is dismissed in early April, almost the exact same time the CDC itself reversed course and recommend facemasks outside which was explicitly at th

  • by hdyoung ( 5182939 ) on Saturday July 18, 2020 @11:29AM (#60304101)
    It's too late to be pro-active on this. The right-wing media has already gotten a hold of it. Once those people commit to a position, they... simply... will... not... budge. Not for decades. This happens over, and over, and over again. In order to make progress, society has to move PAST the conservatives and leave them behind. They will get dragged along, kicking and screaming and loudly complaining, at some later point in time. They will ALWAYS be behind the times. That's literally the definition of the word "conservative".

    This happened with the state-level adoption of mandatory seat belts. Yes, it's an imposition on individual rights. While individual rights are extremely important in western society, they aren't infinite.

    It also happened with "no shoes no shirt no service" in the commercial sector. Yes, you might feel that it's your god-given right to wander into a store and leave a steaming trail of fungal toe-jam behind you, but the proprietor says otherwise. Suck it up, buttercup. You don't always get to set the rules.

    Its currently happening right now with regards to LGBTs. A huge chunk of society has decided that LGBTs are actual people and actual citizens, just like everyone else, with the exact same set of rights and responsibilities. Yes, several religions consider them to be sub-human. Too firkin bad. As a civilization, we've decided otherwise. Preach whatever homophobic crap you want in your place of worship. Beyond those walls, you will follow the new rules or run afoul of the law and face the consequences. Keep on lobbying for religious exemptions. That will buy you another decade or so. Eventually, you WILL follow the trail of progress. Like it. Or not.

    It's going to happen with masks. It's just going to take time. Walmart now requires masks in their stores. And they're enforcing it. Whatcha gonna do now, middle America?
    • The stupidity swings both ways. Oregon exempted "people of color" from mask wearing mandates, because of an alleged inherent bias against minorities who wear face coverings. So instead of taking this chance to erase that bias from society, they've decided to reinforce an "us vs. them" mentality while also putting minorities at greater risk of exposure by discouraging mask wearing.
  • by GrahamJ ( 241784 )

    but ma freedum to get sick!

  • by TomR teh Pirate ( 1554037 ) on Saturday July 18, 2020 @12:01PM (#60304253)
    If I'm in a retail store like Target and see somebody who has their nose exposed, I politely let them know that the mask doesn't work in that configuration. When they mumble some lame response I respond with, "oh, I'm telling you for your own protection and not mine. See, I'm currently infected with COVID." And just like that, they pull the mask up. If people aren't going to wear masks for the safety of others, I'm all too happy to use their selfishness against them.
  • Medical masks have existed for (I am guessing here) probably over a century at this point. I know plague doctors had special masks. Additionally, like the article points out there have been whole populations who have been wearing masks for decades.

    And it is just now while the politicians are trying to force people to wear masks that we find that they actually protect the wearer? It is simply 100% impossible that some medical establishment, or county would not have already tested theses masks. Is this articl

You will have many recoverable tape errors.

Working...