6 ms·

I'm part of a mask-providing charity. [1] This article is misleading in three ways: 1) It acts as if a single person speaks for #Masks4All. But #Masks4All is

by toomim 7y ago

I'm part of a mask-providing charity. [1] This article is misleading in three ways: 1) It acts as if a single person speaks for #Masks4All. But #Masks4All is a hashtag, not a person. 2) It says that #Masks4All claims cloth masks are 96% effective. I've never heard that. We always claim cloth masks are 30% effective, surgical masks are 60-80%, and N95 masks are 95% effective. 3) It says that cloth masks are 70% effective, and then exaggerates this to say that cloth masks are "not effective." Who in their right mind would say that "70% effective" means "not effective?" [1] https://maskedprotectors.org/ https://maskedprotectors.org/

kerkeslager 7y ago
> 1) It acts as if a single person speaks for #Masks4All. But #Masks4All is a hashtag, not a person. This is always a big indicator that someone has no idea what's going on on the internet. A similar trend goes for almost anyone who talks about "anonymous".
jawns 7y ago
There are a bunch of variables here that we need to know to be able to say whether any type of mask reduces the likelihood of infecting others, and the percentage of viral particles filtered by the mask is just one of them. Another key factor is the rate at which the risk of infection changes depending on the percentage of particles filtered. For instance, it's conceivable that you can be equally likely to be infected whether 5% or 95% of particles are filtered, depending on the "potency" of the particles that are not filtered. If contact with just N particles increases a person's likelihood of infection by some percentage, and the average cough transmits 100N particles, then even if you filter out 95% of those, you're still at 5N. But we know that in most cases, increasing the percentage of filtered particles maps in some way (though maybe not linearly) with reducing the number of infections. All that is to say: I think we need to be careful about using this one variable -- percentage of particles filtered -- when talking about effectiveness of masks. Effectiveness is more of a holistic calculation, taking into account viral potency, the distance unfiltered viral particles travel through the mask, the degree to which they linger in the air, etc.
- clairity 7y ago
  yes, please keep adding level-headed reasoning to the conversation despite the continuing public panic over the topic. another major confounding variable that makes those effectiveness claims misleading is the environment in which they're used. ENT surgeons (and their patients) are absolutely positively at heightened risk by literally being in the face of patients for prolonged periods. they should use all sorts of countermeasures, including surgical masks. the typical person on the street gains no added benefit from wearing a mask, regardless of the effectiveness of a given mask at blocking particles, as the ambient viral concentration is effectively non-existent basically everywhere outside, assuming most folks aren't congregating (closely and face-to-face) regularly. even in most indoor situations, mask effectiveness only comes into play in very specific situations. if no one shoots the ball, you can't block their shot, no matter how great a shot-blocker you are. latching onto miraculous prophylactics without skepticism and thought is a danger in itself.
  - jawns 7y ago
    > even in most indoor situations, mask effectiveness only comes into play in very specific situations. I think you might be underestimating how transmissible this particular virus is. If it were that hard to catch it, people wouldn't be catching it at the rate they are.
    - clairity 7y ago
      no, note that the confirmed infection rate as of this morning in CA is 0.1% (~40K out of ~40M). because of the roughly 2-3 week lag in effects, the moderation of that rate is mostly attributable to modest distancing rules, before masks were widely encouraged.
      - seafoam 7y ago
        21% here in NYC. [0] Note that this finding is materially different from zero, unlike the Stanford study. [1] Big picture : Don't be misled by the confirmed case count. [0] https://www.reddit.com/r/COVID19/comments/g6pqsr/nysnyc_antibody_study_updates/ https://www.reddit.com/r/COVID19/comments/g6pqsr/nysnyc_anti... [1] https://statmodeling.stat.columbia.edu/2020/04/19/fatal-flaws-in-stanford-study-of-coronavirus-prevalence/ https://statmodeling.stat.columbia.edu/2020/04/19/fatal-flaw...
bambax 7y ago
> It says that cloth masks are 70% effective, and then exaggerates this to say that cloth masks are "not effective." No. It says that the main South Korean study "found" that masks were 70% effective, but that that study is not significant, because it was based on only 4 people, "one of whom could not produce detectable virus particles even without a mask" -- so really, 3 people. It also says that a much more important study [1], based on 1607 hospital workers found that penetration of cloth masks by particles was almost 97%. That other study was made in 2015, so before covid, but there is no reason to believe its results would be different with the covid virus; it's certainly not disproved by a study based on 3 people. [1] https://bmjopen.bmj.com/content/5/4/e006577 https://bmjopen.bmj.com/content/5/4/e006577
- DanBC 7y ago
  Also, the 4 person South Korean study was very clear in their conclusion: https://annals.org/aim/fullarticle/2764367/effectiveness-surgical-cotton-masks-blocking-sars-cov-2-controlled-comparison https://annals.org/aim/fullarticle/2764367/effectiveness-sur... > In conclusion, both surgical and cotton masks seem to be ineffective in preventing the dissemination of SARS–CoV-2 from the coughs of patients with COVID-19 to the environment and external mask surface.
  - jtoomim 7y ago
    That study is n=4. They didn't have enough statistical power to make any conclusions of that sort. Incidentally, if you look at the SK study's actual data, it appears that the cloth and surgical masks reduced the concentration of the virus by about 0.5 to 1.0 log units -- that is, by 66% to 90%. However, those results results were not statistically significant, because n=4. Nancy Leung, from Benjamin Cowling's lab in Hong Kong, did a much better study, n=114. They found that surgical masks did confer significant protective benefits. https://www.nature.com/articles/s41591-020-0843-2.pdf https://www.nature.com/articles/s41591-020-0843-2.pdf
  - jnbiche 7y ago
    First, each patient coughed directly upon a petri dish 20 cm away, not once but 5 times. I don't think anyone would rationally believe that a non-fitted mask would have a high probability of providing protection to a person directly coughed on by an infectious mask-wearer, all at a distance of 20cm. If they were going to test under those conditions, they should have used an N95 mask. Doing it with a surgical mask under such conditions was a waste of time and no surprise at all. The argument has never been that non-fitted masks prevent 100% of all viral particles emitted by an infectious person from escaping into the environment (which is what that tests, since it only takes a few virions to start a colony in a culture). The argument has been that wearing a non-fitted mask can significant decrease the amount of virus-laden droplets floating around in the air, and falling onto surfaces. The more we find out about asymptomatic carriers, the more this makes sense. These carriers aren't going around coughing their lungs out, they transmitting disease by talking and breathing. A mask likely helps a lot with that. I've really like to see the same experiment repeated, but with the patient wearing the mask and talking, and the petri disk held ~2 meters away. These are the conditions under which the disease is being transmitted now, outside of households and healthcare facilities.
DanBC 7y ago
> 1) It acts as if a single person speaks for #Masks4All. But #Masks4All is a hashtag, not a person. The article is referring to Jeremy Howard who set up Masks 4 All, and coordinated a little bit of research around the effectiveness of masks. https://masks4all.co/in-the-media/ https://masks4all.co/in-the-media/ https://www.fast.ai/2020/04/13/masks-summary/ https://www.fast.ai/2020/04/13/masks-summary/ His messaging is a bit frustrating because he misrepresents the science, he says stuff that's anti-science, and he's pretty dogmatic.
- toomim 7y ago
  He owns the domain masks4all.co, and set up that one particular website, but he does not own the #masks4all subreddit [1], youtube tag [2], twitter tag [3], or the variety of other #masks4all websites such as maskssavelives.org [4] and maskedprotectors.org [5]. [1] https://old.reddit.com/r/Masks4All/ https://old.reddit.com/r/Masks4All/ [2] https://www.youtube.com/results?search_query=%23masks4all https://www.youtube.com/results?search_query=%23masks4all [3] https://twitter.com/search?q=%23Masks4All https://twitter.com/search?q=%23Masks4All [4] https://maskssavelives.org https://maskssavelives.org [5] https://maskedprotectors.org https://maskedprotectors.org This article is falsely presuming that Jeremy Howard is the leader of the masks4all movement in order to lambast the movement. If it wanted to disagree with Jeremy Howard, or masks4all.co, it should put that in the title. Not #Masks4All.
martingoodson 7y ago
'It says that #Masks4All claims cloth masks are 96% effective. I've never heard that. We always claim...' Author of the article here: this is from the masks4all.co website: 'If you have COVID-19 and cough on someone from 8 inches away, wearing a cotton mask will reduce the amount of virus you transmit to that person by 36 times...' A 36-fold reduction is equivalent to a 96% reduction.
marcosdumay 7y ago
> It says that cloth masks are 70% effective, and then exaggerates this to say that cloth masks are "not effective." This caught my eyes too. If we had a simple way to reduce the virus dissemination by 70%, we would be able to finish the entire pandemic in a couple of months.
tinus_hn 7y ago
> Who in their right mind would say that "70% effective" means "not effective?" People who want to keep being scared into indefinite quarantine (which unfortunately does require the same from everyone else). If questioned they’ll mention some really undefined requirements so they can keep moving the goalposts.

by toomim 7y ago

kerkeslager 7y ago

> 1) It acts as if a single person speaks for #Masks4All. But #Masks4All is a hashtag, not a person. This is always a big indicator that someone has no idea what's going on on the internet. A similar trend goes for almost anyone who talks about "anonymous".

jawns 7y ago

There are a bunch of variables here that we need to know to be able to say whether any type of mask reduces the likelihood of infecting others, and the percentage of viral particles filtered by the mask is just one of them. Another key factor is the rate at which the risk of infection changes depending on the percentage of particles filtered. For instance, it's conceivable that you can be equally likely to be infected whether 5% or 95% of particles are filtered, depending on the "potency" of the particles that are not filtered. If contact with just N particles increases a person's likelihood of infection by some percentage, and the average cough transmits 100N particles, then even if you filter out 95% of those, you're still at 5N. But we know that in most cases, increasing the percentage of filtered particles maps in some way (though maybe not linearly) with reducing the number of infections. All that is to say: I think we need to be careful about using this one variable -- percentage of particles filtered -- when talking about effectiveness of masks. Effectiveness is more of a holistic calculation, taking into account viral potency, the distance unfiltered viral particles travel through the mask, the degree to which they linger in the air, etc.

clairity 7y ago
yes, please keep adding level-headed reasoning to the conversation despite the continuing public panic over the topic. another major confounding variable that makes those effectiveness claims misleading is the environment in which they're used. ENT surgeons (and their patients) are absolutely positively at heightened risk by literally being in the face of patients for prolonged periods. they should use all sorts of countermeasures, including surgical masks. the typical person on the street gains no added benefit from wearing a mask, regardless of the effectiveness of a given mask at blocking particles, as the ambient viral concentration is effectively non-existent basically everywhere outside, assuming most folks aren't congregating (closely and face-to-face) regularly. even in most indoor situations, mask effectiveness only comes into play in very specific situations. if no one shoots the ball, you can't block their shot, no matter how great a shot-blocker you are. latching onto miraculous prophylactics without skepticism and thought is a danger in itself.
- jawns 7y ago
  > even in most indoor situations, mask effectiveness only comes into play in very specific situations. I think you might be underestimating how transmissible this particular virus is. If it were that hard to catch it, people wouldn't be catching it at the rate they are.
  - clairity 7y ago
    no, note that the confirmed infection rate as of this morning in CA is 0.1% (~40K out of ~40M). because of the roughly 2-3 week lag in effects, the moderation of that rate is mostly attributable to modest distancing rules, before masks were widely encouraged.
    - seafoam 7y ago
      21% here in NYC. [0] Note that this finding is materially different from zero, unlike the Stanford study. [1] Big picture : Don't be misled by the confirmed case count. [0] https://www.reddit.com/r/COVID19/comments/g6pqsr/nysnyc_antibody_study_updates/ https://www.reddit.com/r/COVID19/comments/g6pqsr/nysnyc_anti... [1] https://statmodeling.stat.columbia.edu/2020/04/19/fatal-flaws-in-stanford-study-of-coronavirus-prevalence/ https://statmodeling.stat.columbia.edu/2020/04/19/fatal-flaw...

bambax 7y ago

> It says that cloth masks are 70% effective, and then exaggerates this to say that cloth masks are "not effective." No. It says that the main South Korean study "found" that masks were 70% effective, but that that study is not significant, because it was based on only 4 people, "one of whom could not produce detectable virus particles even without a mask" -- so really, 3 people. It also says that a much more important study [1], based on 1607 hospital workers found that penetration of cloth masks by particles was almost 97%. That other study was made in 2015, so before covid, but there is no reason to believe its results would be different with the covid virus; it's certainly not disproved by a study based on 3 people. [1] https://bmjopen.bmj.com/content/5/4/e006577 https://bmjopen.bmj.com/content/5/4/e006577

DanBC 7y ago
Also, the 4 person South Korean study was very clear in their conclusion: https://annals.org/aim/fullarticle/2764367/effectiveness-surgical-cotton-masks-blocking-sars-cov-2-controlled-comparison https://annals.org/aim/fullarticle/2764367/effectiveness-sur... > In conclusion, both surgical and cotton masks seem to be ineffective in preventing the dissemination of SARS–CoV-2 from the coughs of patients with COVID-19 to the environment and external mask surface.
- jtoomim 7y ago
  That study is n=4. They didn't have enough statistical power to make any conclusions of that sort. Incidentally, if you look at the SK study's actual data, it appears that the cloth and surgical masks reduced the concentration of the virus by about 0.5 to 1.0 log units -- that is, by 66% to 90%. However, those results results were not statistically significant, because n=4. Nancy Leung, from Benjamin Cowling's lab in Hong Kong, did a much better study, n=114. They found that surgical masks did confer significant protective benefits. https://www.nature.com/articles/s41591-020-0843-2.pdf https://www.nature.com/articles/s41591-020-0843-2.pdf
- jnbiche 7y ago
  First, each patient coughed directly upon a petri dish 20 cm away, not once but 5 times. I don't think anyone would rationally believe that a non-fitted mask would have a high probability of providing protection to a person directly coughed on by an infectious mask-wearer, all at a distance of 20cm. If they were going to test under those conditions, they should have used an N95 mask. Doing it with a surgical mask under such conditions was a waste of time and no surprise at all. The argument has never been that non-fitted masks prevent 100% of all viral particles emitted by an infectious person from escaping into the environment (which is what that tests, since it only takes a few virions to start a colony in a culture). The argument has been that wearing a non-fitted mask can significant decrease the amount of virus-laden droplets floating around in the air, and falling onto surfaces. The more we find out about asymptomatic carriers, the more this makes sense. These carriers aren't going around coughing their lungs out, they transmitting disease by talking and breathing. A mask likely helps a lot with that. I've really like to see the same experiment repeated, but with the patient wearing the mask and talking, and the petri disk held ~2 meters away. These are the conditions under which the disease is being transmitted now, outside of households and healthcare facilities.

DanBC 7y ago

> 1) It acts as if a single person speaks for #Masks4All. But #Masks4All is a hashtag, not a person. The article is referring to Jeremy Howard who set up Masks 4 All, and coordinated a little bit of research around the effectiveness of masks. https://masks4all.co/in-the-media/ https://masks4all.co/in-the-media/ https://www.fast.ai/2020/04/13/masks-summary/ https://www.fast.ai/2020/04/13/masks-summary/ His messaging is a bit frustrating because he misrepresents the science, he says stuff that's anti-science, and he's pretty dogmatic.

toomim 7y ago
He owns the domain masks4all.co, and set up that one particular website, but he does not own the #masks4all subreddit [1], youtube tag [2], twitter tag [3], or the variety of other #masks4all websites such as maskssavelives.org [4] and maskedprotectors.org [5]. [1] https://old.reddit.com/r/Masks4All/ https://old.reddit.com/r/Masks4All/ [2] https://www.youtube.com/results?search_query=%23masks4all https://www.youtube.com/results?search_query=%23masks4all [3] https://twitter.com/search?q=%23Masks4All https://twitter.com/search?q=%23Masks4All [4] https://maskssavelives.org https://maskssavelives.org [5] https://maskedprotectors.org https://maskedprotectors.org This article is falsely presuming that Jeremy Howard is the leader of the masks4all movement in order to lambast the movement. If it wanted to disagree with Jeremy Howard, or masks4all.co, it should put that in the title. Not #Masks4All.

martingoodson 7y ago

'It says that #Masks4All claims cloth masks are 96% effective. I've never heard that. We always claim...' Author of the article here: this is from the masks4all.co website: 'If you have COVID-19 and cough on someone from 8 inches away, wearing a cotton mask will reduce the amount of virus you transmit to that person by 36 times...' A 36-fold reduction is equivalent to a 96% reduction.

marcosdumay 7y ago

> It says that cloth masks are 70% effective, and then exaggerates this to say that cloth masks are "not effective." This caught my eyes too. If we had a simple way to reduce the virus dissemination by 70%, we would be able to finish the entire pandemic in a couple of months.

tinus_hn 7y ago

> Who in their right mind would say that "70% effective" means "not effective?" People who want to keep being scared into indefinite quarantine (which unfortunately does require the same from everyone else). If questioned they’ll mention some really undefined requirements so they can keep moving the goalposts.