A DIY face mask and other ways to fight the Corona virus

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  • 12 Apr 2020 18:38
    Reply # 8894827 on 8890242
    Anonymous wrote:

    One thing that this paper calling for mask use states, that is completely consistent with the rest of the literature, is that mask use is only effective when there is a very high degree of compliance and that masks are worn with great skill.  Thus, each of you can watch those around you and judge whether you and your community are actually being made safer by mask use.  

    I wish those governments choosing to mandate face masks would announce that facemasks don't really work, but we're going to try anyway.  At least then, people might still observe physical distancing. 

    Physical distancing... watch for pets. I have watched here and on some videos the people being very careful not to be too close to other people but then petting dogs that are off leash. Pets are not likely to get sick and may not be a carrier but they are a moving possibly contaminated "surface". So yes walk your dog. Say away from any off leash areas ((keep your dog on a leash). watch out for other dogs that are off leash and maybe choose a different route to avoid known off lease dogs. Animals do not understand distancing.
  • 09 Apr 2020 20:54
    Reply # 8890242 on 8855224

    David, I think it is fair to say that the paper you cite is not at all a balanced look at the data.  Even doctors and nurses suffer from self-infection when removing masks, the paper doesn't mention this at all.  They use the commonly cited anecdotal examples of the singing choirs (both in Korea and the US) getting infected as an example of airborne transmission, while ignoring the existing data that shows singing is only third to sneezing and coughing in producing coarse and fine droplets, while breathing produces very little and talking only a bit more.  This is an argument for staying away from public gatherings with mass singing, not face masks.  They cite the same study I did earlier in this thread about cloth face masks.  However, the authors minimise the problems with cloth mask use and state:

    "A three arm trial of cloth masks versus surgical masks versus “standard practice” in preventing influenza-like illness in healthcare staff found that cloth masks were the least effective, but “standard practice” usually involved a surgical face mask and there was no true control arm with no masks."

    If you look at the original study you can see that the "standard practice" control arm had a wide variety of mask use, it included no masks, medical masks, a few N95 and even cloth masks.  The control arm also only had half the compliance with mask wearing compared to the cloth mask group (yes the control group only wore any kind of mask half the time compared to the cloth mask group).  Yet, the cloth masks were still three times more likely to make the wearers sick compared to the control group.  Compared to the medical mask group, cloth masks were thirteen times more likely to make wearers sick.  In other words, there is a very real possibility that there is something to lose by just hoping for the best and giving cloth mask a try.

    One thing that this paper calling for mask use states, that is completely consistent with the rest of the literature, is that mask use is only effective when there is a very high degree of compliance and that masks are worn with great skill.  Thus, each of you can watch those around you and judge whether you and your community are actually being made safer by mask use.  

    I wish those governments choosing to mandate face masks would announce that facemasks don't really work, but we're going to try anyway.  At least then, people might still observe physical distancing. 

    Regardless of whether you want masks or not, be careful that they don't take away from a focus on testing.  Mass testing, identifying infected people, and quarantining them and their immediate contacts is the single best bet we have for saving lives and getting back to work in the near term.  It might be worth talking to people around you (from a safe distance) about how invasive of measures your community is willing to endure to keep people safe.  A month ago I thought South Korea's mandatory installation of a tracking app on the cellphone of anyone testing positive was a bit invasive.  Today, I wonder if even that is going far enough.  You could leave your phone behind, maybe GPS ankle bracelets or a 3D printed thingy to permanently attach your phone to you....

    To help keep each of you safe, please remember that a mask can easily become a source of infection to you and others.  Handle it only from the straps, not the shield.  Disinfect your hands after you remove it.  Everything your hands or a used mask touches is a source for disease.  If you are using a cloth mask your'e going to need a way to quarantine it between when you remove it and when you can sterilise it.   If someone coughs into a mask there are still viral particles being dispersed outside the mask, there are less coarse droplets but little change in finer droplets.  Keep your mask dry, both in storage, but also on your face.  If it is wet it is more dangerous, change to a dry mask.  Be thorough in how you sterilise a cloth mask.  Do not re-use disposable masks.

    Take care everyone,


    Last modified: 09 Apr 2020 21:09 | Anonymous member
  • 09 Apr 2020 18:59
    Reply # 8889998 on 8855224
    Anonymous member (Administrator)

    Well it’s about time!

    The position, which The British Medical Journal and others now take, is just about exactly the same as I wrote up in my first few paragraphs of my write-up.
    ( https://bit.ly/2WBAq9y )

    Then there were no masks available for ordinary people in Norway, and I think they are still difficult to get here, as hospitals have first priority. I suspect that the reason why the officials advised against using masks to begin with, simply was that there were no masks available...

    Therefore the DIY-masks.

    (..I just had to rub it in...)

  • 09 Apr 2020 17:20
    Reply # 8889847 on 8855224

    It’s time to encourage people to wear face masks as a precautionary measure on the grounds that we have little to lose and potentially something to gain, said experts in The British Medical Journal today.

    Prof Trisha Greenhalgh at the University of Oxford and colleagues say that despite limited evidence, masks “could have a substantial impact on transmission with a relatively small impact on social and economic life.”


    Although clinical trial evidence on the widespread use of face masks as a protective measure against Covid-19 is lacking, at the time of writing increasing numbers of agencies and governments, including the US Centers for Diseases Control and Prevention, are now advocating that the general population wears masks, but others, such as the World Health Organization and Public Health England are not.

    Greenhalgh and colleagues argue that people could be taught to use masks consistently and not abandon other important anti-contagion measures (e.g hand-washing), and political will could ensure that mask shortages can be overcome by repurposing manufacturing capacity (something which is already happening informally).

    They conclude that it is time to act without waiting for randomised controlled trial evidence, writing:

    Masks are simple, cheap, and potentially effective.We believe that, worn both in the home (particularly by the person showing symptoms) and also outside the home in situations where meeting others is likely (for example, shopping, public transport), they could have a substantial impact on transmission with a relatively small impact on social and economic life.

  • 07 Apr 2020 09:46
    Reply # 8883150 on 8881916
    Anonymous wrote:


    As for this test of clots for home-made facemasks; is that of no value?



    Oh Arne, I really do hope we get a chance to have a beer some day, I think we share curiosity and commitment.  I think the short answer is that the filtering efficiency of the material is only a small part of the equation of whether a mask is worthwhile or not.  

    I expect most of you won't read below this line.  If you intend to, I would suggest you get a beer, I certainly had some while I composed it.

    If you like I can dig up the numbers, regarding filtration efficiency, vs coarse droplets and aerosols.  I can't remember the numbers off the top of my head.  Cloth masks definitely placed a distant last, even compared to surgical masks, which are a poor cousin to N95 masks.  There is some data on this because it would be so attractive if cloth masks could be reused in the developing world, unfortunately the conclusions were that cloth masks were sufficiently permeable not to be effective.

    However, I also think figuring out the filtration efficiency of a cloth mask is the wrong question to ask.  I've now read more papers than I care to about masks.  The field is full of research that looks at particle sizes because these are easy to measure.  With the advent of PCR RNA testing, you also find studies that can now identify viruses on all sorts of surfaces and even in air samples.  However, this is just the trace DNA of the virus and it may very well not be infectious at all.  

    I think the endpoint of a study on mask usefulness needs to be how you keep as many people as healthy as you can.  Thus, the most sensible endpoint to measure is how many people get sick from a randomly selected group of folks assigned to either wear a particular mask or not wear a mask.  Or as they did in a flu study, how many people around an infected person get sick if the infected person wears a mask.  Such studies not only account for filtration efficiency and viability of virus particles but also social behaviour and how effectively the masks are worn.  Sadly, there is not a good study that addresses this exact question for Covid-19.  There are lots of ways mask wearing can be ineffective.  Different diseases spread differently, most important is the minimum droplet size the virus remains viable in and whether the disease can spread by aerosol (very tiny droplets that float in the air rather than settling out).  If the disease can spread by aerosol then a cloth mask is about as useful as breathing through mosquito screen (please excuse the slight exaggeration) both for reducing the spread of particles and for protecting you.  Similarly, if a mask works perfectly, but you contaminate yourself as you put it on, or remove it, the overall protection is still nil.  Or, if you think you can safely cough into the mask, but it is still allowing significant particles out, you can unintentionally infect others.   The list is long, but I'm sure you get the point that the filtering efficiency of the mask is only one element in the equation.

    Almost all the news reports lately that support the use of masks fail to consider that there are ways where masks can also decrease safety.  One of the studies I cited here earlier showed that respiratory infections were worse amongst hospital workers who properly and regularly wore cloth facemasks compared to their coworkers that sometimes wore surgical masks and sometimes didn't wear a mask at all.  That study included Coronavirus, but not the Covid-19 version.   Another study showed a statistically insignificant difference of risk to family members catching the flu whether or not an infected member wore a mask.  The researchers in that study thought small samples sizes were the reason they didn't see a significant result, but with over 120 patients in each group, if there were much of an effect they should have seen it.  If you're expecting to protect others, but not really doing it, that is also a problem.

    It is the entire system that matters.  For an example, as you watch the news tonight, or on your next shopping trip, watch for the person that pulls their surgical mask down over their chin to talk or take a breathing break.  Pulling the inside of their mask down over their dirty chin/neck, which they've likely touched while adjusting the mask, contaminates the inside of the mask.  Even though it may be not a lot of contamination you have put it in a great environment to stay viable inside the mask.  Every breath after that is a chance to breath it in and if they reuse the mask things get worse every time it goes on and off. Even for medical professionals trained in donning and doffing protective gear, the point of greatest risk is each time you remove or adjust a mask or other gear.  

    As you experienced with your mask experiments Arne, as the filtration efficiency gets better, it gets harder to breath.  As it gets harder breath people find masks less comfortable to wear and thus adjust them more regularly and are less compliant with wearing a mask as they should.  So, you end up with either a mask that doesn't filter very well and people wear, or you get masks that filter well, but that even many medical personal don't like to wear for a long time due to discomfort and greater difficulty breathing.

    I wish masks worked better, it would be so nice to have a solution that would keep people safer and allow everyone to get back to work sooner.  

    I'm really fortunate to live in place where the politicians have got out of the way and turned the decisions over to the medical professionals.  As you can imagine, the Canadian public has had quite a few questions about mask use after the American presidential and CDC recommendations.  Today our provincial health officer (an exceptionally reasonable, science-based decision maker) announced (after our national review in response to the American recommendations on masks) that they are not recommending the use of face masks, but are being permissive about their use as long as they are not surgical or medical (N95) masks.  Basically, cloth masks could be used if you are in a very crowded setting (which they say you shouldn't do anyway) or think there is a chance you could not be able to cough into the crook of your elbow should the need to cough arise (although you should not go out if you have any coughing).  Here is a link to today's updated epidemic curve for BC, which is a place where a respected health officer has said masks are not necessary and a majority of people are not wearing masks.  We have however, done quite a bit of testing (for a while our little province had done more than the entirety of the US), and we did start social distancing very early in our outbreak.

    When we started this conversation, I was concerned that your use of the mask would encourage others (more those that saw you than those reading this thread) and that they would buy N95 or surgical masks that would further deplete the supply for healthcare workers.  That now seems like a long time ago and increasingly such masks are being directed solely to healthcare providers, so this concern is now less relevant.  I think the way you are using your mask is sensible Arne and given the messaging from many governments you certainly won't be alone.  I think it would be nice if you could get some hand sanitizer to use after you remove the mask outside the grocery store and have quarantined the mask in a plastic baggie (or reusable Tupperware) until you can sterilise it. 

    I should also say that all this is relevant to the current circumstances most of us face which includes physical distancing and staying at home if you are sick.  If I had to ride a packed subway train, with others that were coughing, or if I were coughing, then the scales probably tip in favour of wearing a mask, because all the most useful methods for reducing the spread of the virus have been lost and you're stuck with whatever you can do.  A cloth mask would not be my first choice in this setting though.  I suppose if I had no other options I'd sew a cloth mask and wear it knowing that I'd still have to do everything possible to make sure I didn't cough towards anyone or even in the direction of surfaces likely to be touched.  Similarly, if I was somewhere where it was mandated to wear face protection, I'd do it for the importance of social cohesion, but I'd still be working harder at social distancing and hand washing.

    Last modified: 07 Apr 2020 18:28 | Anonymous member
  • 06 Apr 2020 17:51
    Reply # 8881916 on 8855224
    Anonymous member (Administrator)


    even if top quality masks were available to everyone, I would still not recommend anyone to drop today’s good safety practice of keeping distance, washing hands etc. It is the sum of these practices which together contribute to bring that R-number(?) below 1.

    The use of a facemask is no excuse for acting stupid among other people, more that using a seatbelt is an excuse for madman-driving.

    As for this test of clots for home-made facemasks; is that of no value?



  • 06 Apr 2020 16:49
    Reply # 8881726 on 8855224

    Well, hopefully we all agree that home-made masks are ineffective enough that if they cause any change in the other recommended behaviours they are likely to make things worse.  Physical distancing, abundant hand washing, staying isolated if you have any kind of symptoms, even mild.  In the next month, expanded testing and contact tracing to keep the infection at low levels.  Next, in a year or more we hope we'll find a new way to make a vaccine for Coronavirus.

    Take care everyone, I'd very much like the opportunity to meet you at a future Junket.  There are more than a few people here that I'd like to buy a beer for the generosity in which they share their knowledge and time.  

  • 06 Apr 2020 12:44
    Reply # 8881204 on 8855224
    Anonymous member (Administrator)

    Here is what I found on one of the pages in New York Times:


    "Frequently Asked Questions and Advice

    Updated April 4, 2020

    ·         Should I wear a mask?

    The C.D.C. has recommended that all Americans wear cloth masks if they go out in public. This is a shift in federal guidance reflecting new concerns that the coronavirus is being spread by infected people who have no symptoms. Until now, the C.D.C., like the W.H.O., has advised that ordinary people don’t need to wear masks unless they are sick and coughing. Part of the reason was to preserve medical-grade masks for health care workers who desperately need them at a time when they are in continuously short supply. Masks don’t replace hand washing and social distancing."



    My point in advocating the use of a mask, even if one feels fine, is that half of those who are infected, don't notice anything...


  • 06 Apr 2020 00:35
    Reply # 8880495 on 8855224

    After my last post I went into the backyard to work on the boat for a bit, while doing so I considered that in the spirit of this thread I should also be offering a way to fight Coronavirus.  The best I could come up with (besides all the sensible things we've already discussed) is to check up on your governments efforts in testing.  It looks like some of us are beginning to come out of the first outbreak, while some will still be in it for longer.  Once new cases start to get back down, one of the most important parts of preventing a recurrent outbreak will be abundant, fast and readily available testing.  If watching your news doesn't have you convinced that your government is on top of testing, contact your local federal politician and let him/her know that you're watching.  I apologise that it's not a very satisfying suggestion.

  • 05 Apr 2020 20:26
    Reply # 8880143 on 8879635
    Anonymous wrote:

    This matter of the facemask’s usefulness (or lack of it) seems to have grown out of its original frame.

    Since I am the one who was dumb enough to open this topic, I want to clarify a little.

    As I wrote in my original write-up:

    ·         Making one’s own facemask was to avoid that hospitals run short of masks (or because they already had taken over all of the professional ones).

    ·         The main way of avoiding spreading the virus, is keeping a distance to others.

    ·         I only recommend using the facemask for the short period of time when we need to do some shopping (once a week?). The mask will not be saturated by water in just 20 minutes.

    ·         The mask is meant to protect others from the wearer, not the other way around. It has been found that many don’t get any symptoms, but can still infect others.

    ·         When donning the mask at entering the shop , the mask is clean, with  next to no virus or bacteria (right from the hot steam- iron)

    Simple as that - I just want to reduce the likelihood of infecting others.

    It has been argued that if one is sneezing or coughing, one should stay away, and if one is not sneezing, one doesn’t need the mask. I am not so sure about that. Anyone who has been out in really frosty weather, knows that our breath suddenly becomes visible: Moist condensates and freezes, so we can see it. It is this moist and droplets which I want to stop with my mask.
    In addition to my first test to blow out a lighter’s flame, held in front of the mask (the flame hardly moved), I did another test yesterday:

    Standing in front of a mirror, about 10-15cm away from it, I breathed (panted), and dew formed on the mirror, as expected. I then repeated the exercise with the mask on. The result was that no dew formed on the mirror.
    I therefore conclude that wearing a clean and dry homemade facemask, worn for a short period of time, will be better in protecting the surrounding people, than not wearing that mask.




    Arne, I think we both agree that we all should be doing everything we can to keep as many people safe as possible.  I haven't seen anyone object that all N95 masks should be heading to hospitals.  I think we have all agreed that physical distancing and hand washing are the most effective ways we can slow the spread of Covid-19.

    However, what you are doing is essentially citizen science and as discovery is a process fraught with error, you have made some mistakes.  For example, your experiment breathing on glass is flawed.  Almost all of what you saw was condensing water vapor, which doesn't carry viable virus.  I redid your experiment this morning, but instead used a microscope slide and high magnification on a phase contrast microscope.  What you see is nothing once the condensed water vapor has evaporated again.  That is not to say it is impossible for breathing or speaking to pass along any virus at all.  But, the quantities are very low and unlikely to cause infection.  Even my experiment was flawed in that I really should have coated the inside of my mouth with dye before breathing on the slide to make any droplets easier to see.  Even that experiment is flawed, because it matters whether the is virus viable in the droplets (coarse or aerosol)....

    Rather than making this post even longer, I'd encourage you to read this review and if you find any flaws in it I'd be happy to dig further into the scientific literature if anyone is interested.  If everyone wore and used a mask EXACTLY as Arne does then there probably would be little harm, but also probably little benefit.  If cloth masks alter peoples behaviour so that more effective means of limiting viral spread are compromised, then masks are actually detrimental.  The next time you go grocery shopping note how close the people wearing masks come to you compared to those who are not.  

    Even when it comes to limiting your shedding of virus, masks are not as simple a tool as putting up a wall.

    I started commenting on this thread with the hope of making everyone safer.  I hope, even for those that choose to or are forced to wear masks, that some additional information on how masks work and how to use them safely has been useful.  Please understand that there is nuance in mask use and efficacy.  Cloth masks don't do enough good to help much and can themselves cause problems.  Right now, all the other kinds of masks are in such short supply that they just aren't an option.   Besides, a grocery store is still a very safe place compared to a hospital.

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