“Our findings suggest that a homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection.“
I don't think touching your face is a problem. It is touching your eyes, nose, and mouth. When you are wearing a mask you can't touch your mouth and nose. The "don't touch your face" is a simplification of what people should really be worried about. Rubbing eyes, touching inside the nose, and in the mouth. Sometimes this is advice given.
"However, these masks
would provide the wearers little protection from microorganisms from others persons who are infected with respiratory
diseases. As a result, we would not recommend the use of
homemade face masks as a method of reducing transmission
of infection from aerosols."
I hear you and understand in theory things like surgical masks allow coronaviruses to pass through them. But we've got to stop thinking about wearing masks in absolute terms of "it works" or "it doesn't work". Just like computer security, wearing a mask is one layer of protection. I don't think any reasonable person expects a mask to be foolproof. But when used in conjunction with thorough and frequent hand washing and social distancing measures, I suspect we'll find that wearing a mask is a prudent thing to do, even if it's just a home-made one out of cotton pillowcases or a surgical mask. Masks should not be relied upon in the absence of social distancing and hand washing just as airbags should not be relied upon without wearing a seatbelt.
There's anecdotal evidence from places like Taiwan and Hong Kong that masks are somewhat helpful and very little real evidence that they're harmful except in terms of making masks unavailable to frontline health workers. I firmly believe that in hindsight, public health agencies in the west will realize they did a lot of harm by saying masks were worthless.
Exactly: protection is probabilistic. Hand-washing isn't perfect, social distancing isn't perfect, and therefore in a sense you could say that they also "don't work" -- but they work in the sense that matters, i.e. reducing the spread of the virus.
> But we've got to stop thinking about wearing masks in absolute terms of "it works" or "it doesn't work".
We're not saying that. We're saying masks make you touch your face, and that without training and correct fitting the minimal protection they give is probably countered by the increased risk.
> If the viability of the two coronaviruses is similar, why is SARS-CoV-2 resulting in more cases? Emerging evidence suggests that people infected with SARS-CoV-2 might be spreading virus without recognizing, or prior to recognizing, symptoms. This would make disease control measures that were effective against SARS-CoV-1 less effective against its successor.
> We found that the stability of SARS-CoV-2 was similar to that of SARS-CoV-1 under the experimental circumstances tested. This indicates that differences in the epidemiologic characteristics of these viruses probably arise from other factors, including high viral loads in the upper respiratory tract and the potential for persons infected with SARS-CoV-2 to shed and transmit the virus while asymptomatic.3,4 Our results indicate that aerosol and fomite transmission of SARS-CoV-2 is plausible, since the virus can remain viable and infectious in aerosols for hours and on surfaces up to days (depending on the inoculum shed). These findings echo those with SARS-CoV-1, in which these forms of transmission were associated with nosocomial spread and super-spreading events,5 and they provide information for pandemic mitigation efforts.
I keep hearing that masks make people touch their face. I put to you the following questions:
1. Do frontline healthcare workers also "touch [their] face" when wearing these masks for the same reasons regular people do? I imagine it's to adjust the fit? If the answer is no, is it because they have been educated not to? People, at least where I am in Canada, are being told not to touch our faces already. Can we not just extend the messaging to be "avoid touching your face, even when wearing a mask"?
2. If increased face touching when wearing a mask is truly a problem, would we not expect Hong Kong and Taiwan to have a worse community spread situation? Why is it that they have this contained? Again, the example is anecdotal. But coincidentally, they're both locations that learned from SARS and H1N1 and mask wearing is a foundational part of their public health response.
thing is, sometimes people didnt show symptoms and didnt realise they were infected.
People make homemade mask because its hard to get stock right now. In that case having a simple mask like this make huge difference in preventing the virus spread.
Its not just for protection of yourself, its for protection of others, so I hope people are not discouraged to wear mask
Note that these are results for aerosolized bacteria that tend to hang in the air. The new coronavirus is only spread via droplet transmission, which would make even rudimentary masks way more effective.
TL;DR of the results though: homemade mask filtered ~50-70% and surgical mask ~90-95%. Homemade mask reduced transmission into the air by ~75-80%, surgical mask by ~85%.
I’d imagine at least some of the advice against buying masks is to prevent hoarding and a supply shortage where they are needed most: healthcare workers.
The masks can be counterproductive if used without discipline or training. It's not uncommon to see people adjusting their masks and scratching underneath them constantly. The masks are transformed into virus concentrators and rebreathers.
Are you aware of any studies on this specifically? Sounds very plausible but hard to weigh against the benefit of catching expelled droplets. I imagine the calculus changes depending on age, and whether your primary concern is preventing your own infection vs. transmission to others.
Really grateful for this resource, but the instructions are not exactly clear. Do you take the t-shirt and make it a single layer of cloth or somehow cut the shape into "1 outer layer (≈37 cm × 72 cm) rolled and cut as in panel B with 8 inner layers (<18 cm2) placed inside (against the face)." How do the inner layers stay put?
looks like the 8 layers are sewn to the single layer. Or possibly the innermost is sewn to the outermost and the other 7 layers are put in the resulting pocket.
"Porton Down opened in 1916 as the War Department Experimental Station, shortly thereafter renamed the Royal Engineers Experimental Station, for testing chemical weapons in response to German use of this means of war in 1915. The laboratory's remit was to conduct research and development regarding chemical weapons agents used by the British armed forces in the First World War, such as chlorine, mustard gas, and phosgene."
Related similar study: "Simple Respiratory Protection—Evaluation of the Filtration Performance of Cloth Masks and Common Fabric Materials Against 20–1000 nm Size Particles" talks about SARS and H1N1 sized threats. https://academic.oup.com/annweh/article/54/7/789/202744?fbcl...
The upshot is, masks work, and the simple ones are particularly effective for protecting other people from transmission of infectious droplets from the person wearing the mask.
Does anyone know of a way to be on a list to purchase masks in an ethical manner? I’d like to get one, but only once the needs of the medical community are adequately met.
I keep coming back to the fact that the main point of a mask is to prevent you from touching your own nose and mouth --- NOT to keep the virus from passing directly to your nose and mouth (or vice versa). Advice from doctor who studied coronaviruses for 50 years: https://halegenic.com/coronavirus-covid-19/
I do understand, however, that my point is moot when you consider direct contact with an infected person who is coughing and/or sneezing without cover (and again vice versa).
Interesting, this is the first time I hear that touching fomites is the primary vector of spreading. The CDC page says the opposite:
https://www.cdc.gov/coronavirus/2019-ncov/prepare/transmissi...
But I do appreciate that we still have a lot to learn about the virus, so disinfecting your hands frequently and being careful about what you touch is sound advice.
The other benefit of masks (and probably the main one of DIY masks) would be that it decreases the chance of the wearer infecting others.
Unless the lockdown ends before covid 19 completely dies out, we should all think of what we can do to minimize the destruction.
If a mask doesn't harm the wearer, doesn't take away from the supply needed by medical and other essential personnel, and can help stop or minimize spread from asymptomatic carriers, why not wear one?
It seems that masks might harm the wearer if warn incorrectly. Well, here's some information - https://www.info.gov.hk/info/sars/en/facemask.htm - looks like there are already lots of videos as well. (And they would need to be adequately cleaned, no question.)
Taking away from essential personnel - don't think that's applicable to cloth ones.
And i think most studies show they reduce spread of viruses. Probably not eliminate, but reduce.
So, I certainly intend to wear one - I have 2 on order. And I hope others will too. It won't solve the entire problem, but it can help.
39 comments
[ 2.5 ms ] story [ 94.6 ms ] threadI realise it’s fairly ineffective, but I think it will help me avoid touching my mouth and face.
I have a beard anyway, which I’ve heard makes masks pretty ineffective anyway.
Wish me luck! Haha
Note: I would have bought one... but you know. Everyone else decided their need for them to sit in their cupboard at home was greater.
Even my need is lower than anyone in a medical position.
1) output
2) input
3) social proximity
it's already great
Sounds like common sense
Also wearing a mask, any mask helps normalize wearing masks in public.
Unless it causes people to touch their face more.
There's anecdotal evidence from places like Taiwan and Hong Kong that masks are somewhat helpful and very little real evidence that they're harmful except in terms of making masks unavailable to frontline health workers. I firmly believe that in hindsight, public health agencies in the west will realize they did a lot of harm by saying masks were worthless.
We're not saying that. We're saying masks make you touch your face, and that without training and correct fitting the minimal protection they give is probably countered by the increased risk.
https://www.nih.gov/news-events/news-releases/new-coronaviru...
> If the viability of the two coronaviruses is similar, why is SARS-CoV-2 resulting in more cases? Emerging evidence suggests that people infected with SARS-CoV-2 might be spreading virus without recognizing, or prior to recognizing, symptoms. This would make disease control measures that were effective against SARS-CoV-1 less effective against its successor.
https://www.nejm.org/doi/10.1056/NEJMc2004973
> We found that the stability of SARS-CoV-2 was similar to that of SARS-CoV-1 under the experimental circumstances tested. This indicates that differences in the epidemiologic characteristics of these viruses probably arise from other factors, including high viral loads in the upper respiratory tract and the potential for persons infected with SARS-CoV-2 to shed and transmit the virus while asymptomatic.3,4 Our results indicate that aerosol and fomite transmission of SARS-CoV-2 is plausible, since the virus can remain viable and infectious in aerosols for hours and on surfaces up to days (depending on the inoculum shed). These findings echo those with SARS-CoV-1, in which these forms of transmission were associated with nosocomial spread and super-spreading events,5 and they provide information for pandemic mitigation efforts.
1. Do frontline healthcare workers also "touch [their] face" when wearing these masks for the same reasons regular people do? I imagine it's to adjust the fit? If the answer is no, is it because they have been educated not to? People, at least where I am in Canada, are being told not to touch our faces already. Can we not just extend the messaging to be "avoid touching your face, even when wearing a mask"?
2. If increased face touching when wearing a mask is truly a problem, would we not expect Hong Kong and Taiwan to have a worse community spread situation? Why is it that they have this contained? Again, the example is anecdotal. But coincidentally, they're both locations that learned from SARS and H1N1 and mask wearing is a foundational part of their public health response.
TL;DR of the results though: homemade mask filtered ~50-70% and surgical mask ~90-95%. Homemade mask reduced transmission into the air by ~75-80%, surgical mask by ~85%.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3373043/
"Porton Down opened in 1916 as the War Department Experimental Station, shortly thereafter renamed the Royal Engineers Experimental Station, for testing chemical weapons in response to German use of this means of war in 1915. The laboratory's remit was to conduct research and development regarding chemical weapons agents used by the British armed forces in the First World War, such as chlorine, mustard gas, and phosgene."
https://en.wikipedia.org/wiki/Porton_Down
I bought 60 HEPA bags a month before this disaster started.
https://medium.com/@matthiassamwald/promoting-simple-do-it-y...
The upshot is, masks work, and the simple ones are particularly effective for protecting other people from transmission of infectious droplets from the person wearing the mask.
I do understand, however, that my point is moot when you consider direct contact with an infected person who is coughing and/or sneezing without cover (and again vice versa).
The other benefit of masks (and probably the main one of DIY masks) would be that it decreases the chance of the wearer infecting others.
It would be an easier sell to people if I could just say ,"it's not 100% effective but estimates by studies show it to be about 20% effective"
I'm all for this. Can't hurt and might help.
- they're too hard to use so only medical professionals should have them (including chastising people who had masks laying around for whatever reason)
- they don't do anything anyways
- they only stop you from spreading so nobody should wear them in public (even though asymptotic spreading is known to occur)
If a mask doesn't harm the wearer, doesn't take away from the supply needed by medical and other essential personnel, and can help stop or minimize spread from asymptomatic carriers, why not wear one?
It seems that masks might harm the wearer if warn incorrectly. Well, here's some information - https://www.info.gov.hk/info/sars/en/facemask.htm - looks like there are already lots of videos as well. (And they would need to be adequately cleaned, no question.)
Taking away from essential personnel - don't think that's applicable to cloth ones.
And i think most studies show they reduce spread of viruses. Probably not eliminate, but reduce.
So, I certainly intend to wear one - I have 2 on order. And I hope others will too. It won't solve the entire problem, but it can help.