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posted by Fnord666 on Monday July 27 2020, @03:01PM   Printer-friendly
from the and-they-need-to-actually-fit dept.

Home-made face masks likely need at least 2 layers to curb COVID-19 spread:

Home-made cloth face masks likely need a minimum of two layers, and preferably three, to prevent the dispersal of viral droplets from the nose and mouth that are associated with the spread of COVID-19, indicates a video case study published online in the journal Thorax.

[...] A team of Australian researchers therefore compared the effectiveness of single and double-layer cloth face coverings (175 g/m² cotton fabric, with a thread count of 170/ inch) with a 3-ply surgical face mask (Bao Thach) at reducing droplet spread.

[...] The video recording showed that the 3-ply surgical face mask was the most effective at reducing airborne droplet dispersal, although even a single layer cloth face covering reduced the droplet spread from speaking.

But a double layer covering was better than a single layer in reducing the droplet spread from coughing and sneezing, the recording showed.

This is just one case, added to which several other factors contribute to the effectiveness of cloth face masks, note the researchers. These include the type of material used, design and fit, as well as the frequency of washing.

Nevertheless, based on their observations, a home made cloth mask with at least two layers is preferable to a single layer mask, they say, adding: "Guidelines on home-made cloth masks should stipulate multiple layers."

And they emphasise: "There is a need for more evidence to inform safer cloth mask design, and countries should ensure adequate manufacturing or procurement of surgical masks."

Journal Reference:
Prateek Bahl, Shovon Bhattacharjee, Charitha de Silva, et al. Face coverings and mask to minimise droplet dispersion and aerosolisation: a video case study [$], Thorax (DOI: 10.1136/thoraxjnl-2020-215748)


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  • (Score: 0) by Anonymous Coward on Monday July 27 2020, @07:38PM (7 children)

    by Anonymous Coward on Monday July 27 2020, @07:38PM (#1027262)

    Sweden is so interesting. They are definitely part of the US empire, but they were able to keep their herd immunity policy among intense pressure from the mainstream media (who seem to have the same ownership in Western Europe and America, according to their political line).

  • (Score: 2) by PartTimeZombie on Monday July 27 2020, @10:16PM (6 children)

    by PartTimeZombie (4827) on Monday July 27 2020, @10:16PM (#1027343)

    You're right, Sweden is interesting,

    ...but they were able to keep their herd immunity policy...

    until they realised the herd immunity policy does not work, and Swedes started dying in large numbers.

    Herd immunity works—if you don’t care how many people die [fortune.com]
    Of course, the jury is still out on whether herd immunity will even work, because we don't know yet if getting Covid gives immunity.

    • (Score: 0) by Anonymous Coward on Monday July 27 2020, @10:33PM (3 children)

      by Anonymous Coward on Monday July 27 2020, @10:33PM (#1027352)

      Yeah, large numbers. 6000 out of 10 000 000 according to their failed government. All those 5 994 000 sharing quality time with friends and family, lamenting that their betters didn't place them under house arrest for months, then force them to wear feel-good muzzles.

      • (Score: 0) by Anonymous Coward on Monday July 27 2020, @10:38PM

        by Anonymous Coward on Monday July 27 2020, @10:38PM (#1027354)

        Math is hard. I meant of course the 9 994 000 desperate free survivors crying about their lot.

      • (Score: 3, Funny) by PartTimeZombie on Tuesday July 28 2020, @12:32AM

        by PartTimeZombie (4827) on Tuesday July 28 2020, @12:32AM (#1027427)

        It must be exhausting trying to keep with whether you are obliged to hate Sweden or love them right now.

        Maybe you'll be told to hate and praise them in the same post. I'm sure Fox News will be issuing new orders shortly.

      • (Score: 2) by dry on Tuesday July 28 2020, @01:46AM

        by dry (223) on Tuesday July 28 2020, @01:46AM (#1027459) Journal

        That's a lot of deaths. Here, it is close to 300 out of 5.1 million people. Very few actual orders too, with the only fines for Americans who won't stay in their own country.

    • (Score: 2) by HiThere on Monday July 27 2020, @11:35PM (1 child)

      by HiThere (866) Subscriber Badge on Monday July 27 2020, @11:35PM (#1027394) Journal

      It appears that catching COVID gives an immunity that lasts for years. (There's a bit of inference there, but it's reasonable.) But it may not be a complete immunity.

      The thing is, antibodies appear to last for a couple of months (varies with the individual, but that's an average). But TCell based immunity looks as if it lasts for years. However TCell immunity doesn't work until some cells catch the disease. It's a plausible inference that the reason there are so many "silent spreader" cases is that a lot of people already have TCell based immunity, so the cases of COVID that they catch are so weak that they don't really notice it as anything special. But they can spread it to people who haven't been exposed.
      If this is true, it implies that the current COVID is only different by a couple of mutations from something that's been around for a long time, but which people haven't noticed...or have just thought "well, that was a bad flu this year", even though it was something else.

      Note that this post is full of a lot of suppositions, so don't believe it. But it's based on actual data, so don't disbelieve it either. Just file it under "maybe" and consider what evidence you would expect to find if it were to be true.

      --
      Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
      • (Score: 2) by PartTimeZombie on Tuesday July 28 2020, @12:29AM

        by PartTimeZombie (4827) on Tuesday July 28 2020, @12:29AM (#1027425)

        That was kind of the point I was trying to make.

        TL;DR: We don't know yet.