8 ms·

Masks and distance multiply eachother's effectiveness. Either alone is significantly less effective than both together.

clairity 6y ago
no, that's exactly the misunderstanding that leads to such security theater. distance does nearly all the work. a mask adds marginal benefit when distancing. when not distancing, like on a cramped airplane, a mask is better than nothing and is doing the work. in that scenario, any mask is better than no mask. there is no multiplying going on.
- bryanlarsen 6y ago
  There are counter-examples showing that distance is not sufficient to ensure protection. https://www.businessinsider.com/how-restaurant-air-conditioning-gave-nine-people-covid-china-2020-4 https://www.businessinsider.com/how-restaurant-air-condition...
  - clairity 6y ago
    that example is the only one that ever gets raised, which makes it dubious as more than a fluke incident. though the explanation is nifty, even that has lots of avenues of critique.
    - bryanlarsen 6y ago
      It's not the only one. There are similar analyses of office working spaces.
- shuntress 6y ago
  I would agree that distance is perhaps the more significant factor but it seems like you are trying to say that Transmission(distance + mask) === Transmission(distance) which I find quite hard to believe. Even ignoring the imperfect distancing that is bound to happen in person. For example, rounding a corner at the same time as someone else.
  - clairity 6y ago
    marginal means that adding a mask to distance adds little, likely immaterial, benefit, not absolute zero all the time, as such functional formulations imply. transmission is primarily a function of time and distance, which is why imperfect is probabalistically ok. we've already covered distance. passing someone around a corner is a miniscule additional risk because of the time factor. just don't stop to shoot the shit and you'll be fine.
- nathannecro 6y ago
  Hey, I appreciate that you have an opinion on this matter, but your opinion is directly opposed with scientific evidence on the matter. It turns out that wearing a simple surgical face mask dramatically reduces the detection of coronavirus in a closed laboratory setting over a period of 30 minutes (1). It also turns out that social distancing alone works too (2). Both reduce the R0 (reproduction number) of a disease. Masks reduce the "contagiousness" because fewer infectious droplets make it out into the open. Social distancing and quarantine measures reduce the likelihood of infectious transmission between infected and healthy individuals. This is multiplicative. For the sake of easy numbers, let's assume that wearing a mask captures 90% of infectious droplets and that every meter of distance results in 60% of the droplets in the air to fall to the ground. If a sick individual wearing a mask coughs out 100 starting droplets and is 2 meters away from a healthy individual, the healthy individual will be breathing in 2.5 infectious droplets (100 * 0.10 * 0.50^2). This is multiplicative. For what it's worth, in real-world studies, when the use of face masks and/or social distancing became enforced, the rate at which infectious transmission occurred saw a measurable drop. The introduction of mandates requiring face masks (with social distancing already in effect) saw a 2% decline in the daily growth rate of COVID (3). If you'd like to read more, there is a recent meta-paper that surveys 172 different studies and concludes that: "The findings of this systematic review of 172 studies (44 comparative studies; n=25 697 patients) on COVID-19, SARS, and MERS provide the best available evidence that current policies of at least 1 m physical distancing are associated with a large reduction in infection, and distances of 2 m might be more effective. These data also suggest that wearing face masks protects people (both health-care workers and the general public) against infection by these coronaviruses, and that eye protection could confer additional benefit. However, none of these interventions afforded complete protection from infection, and their optimum role might need risk assessment and several contextual considerations. No randomised trials were identified for these interventions in COVID-19, SARS, or MERS." (4) 1: https://www.nature.com/articles/s41591-020-0843-2 https://www.nature.com/articles/s41591-020-0843-2 2: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30162-6/fulltext https://www.thelancet.com/journals/laninf/article/PIIS1473-3... 3: https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818 https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818 4: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31142-9/fulltext https://www.thelancet.com/journals/lancet/article/PIIS0140-6...
- smileypete 6y ago
  >no, that's exactly the misunderstanding that leads to such security theater. distance does nearly all the work. a mask adds marginal benefit when distancing. FWIW... 'Yuen Kwok-yung, a professor of infectious disease at the University of Hong Kong, has advised his government that all social distancing can be relaxed – but only if people wear masks in enclosed spaces such as on trains and at work, and that no food or drink are consumed at concerts and cinemas.' https://www.theguardian.com/world/2020/may/22/why-we-might-not-get-a-coronavirus-vaccine https://www.theguardian.com/world/2020/may/22/why-we-might-n... (Yuen Kwok-yung is one of, if not the leading infectious disease specialist in Asia among other things, and has his name on many peer reviewed scientific papers.)
  - clairity 6y ago
    that might seem contradictory, but not necessarily. the article doesn't provide enough information to draw a definitive conclusion, but it seems to imply the same order of things later in the article. so distancing as the primary mitigation, masks when you can't, as with trains, concerts, and cinemas (work depends on the office plan).

no, that's exactly the misunderstanding that leads to such security theater. distance does nearly all the work. a mask adds marginal benefit when distancing. when not distancing, like on a cramped airplane, a mask is better than nothing and is doing the work. in that scenario, any mask is better than no mask. there is no multiplying going on.

bryanlarsen 6y ago
There are counter-examples showing that distance is not sufficient to ensure protection. https://www.businessinsider.com/how-restaurant-air-conditioning-gave-nine-people-covid-china-2020-4 https://www.businessinsider.com/how-restaurant-air-condition...
- clairity 6y ago
  that example is the only one that ever gets raised, which makes it dubious as more than a fluke incident. though the explanation is nifty, even that has lots of avenues of critique.
  - bryanlarsen 6y ago
    It's not the only one. There are similar analyses of office working spaces.
shuntress 6y ago
I would agree that distance is perhaps the more significant factor but it seems like you are trying to say that Transmission(distance + mask) === Transmission(distance) which I find quite hard to believe. Even ignoring the imperfect distancing that is bound to happen in person. For example, rounding a corner at the same time as someone else.
- clairity 6y ago
  marginal means that adding a mask to distance adds little, likely immaterial, benefit, not absolute zero all the time, as such functional formulations imply. transmission is primarily a function of time and distance, which is why imperfect is probabalistically ok. we've already covered distance. passing someone around a corner is a miniscule additional risk because of the time factor. just don't stop to shoot the shit and you'll be fine.
nathannecro 6y ago
Hey, I appreciate that you have an opinion on this matter, but your opinion is directly opposed with scientific evidence on the matter. It turns out that wearing a simple surgical face mask dramatically reduces the detection of coronavirus in a closed laboratory setting over a period of 30 minutes (1). It also turns out that social distancing alone works too (2). Both reduce the R0 (reproduction number) of a disease. Masks reduce the "contagiousness" because fewer infectious droplets make it out into the open. Social distancing and quarantine measures reduce the likelihood of infectious transmission between infected and healthy individuals. This is multiplicative. For the sake of easy numbers, let's assume that wearing a mask captures 90% of infectious droplets and that every meter of distance results in 60% of the droplets in the air to fall to the ground. If a sick individual wearing a mask coughs out 100 starting droplets and is 2 meters away from a healthy individual, the healthy individual will be breathing in 2.5 infectious droplets (100 * 0.10 * 0.50^2). This is multiplicative. For what it's worth, in real-world studies, when the use of face masks and/or social distancing became enforced, the rate at which infectious transmission occurred saw a measurable drop. The introduction of mandates requiring face masks (with social distancing already in effect) saw a 2% decline in the daily growth rate of COVID (3). If you'd like to read more, there is a recent meta-paper that surveys 172 different studies and concludes that: "The findings of this systematic review of 172 studies (44 comparative studies; n=25 697 patients) on COVID-19, SARS, and MERS provide the best available evidence that current policies of at least 1 m physical distancing are associated with a large reduction in infection, and distances of 2 m might be more effective. These data also suggest that wearing face masks protects people (both health-care workers and the general public) against infection by these coronaviruses, and that eye protection could confer additional benefit. However, none of these interventions afforded complete protection from infection, and their optimum role might need risk assessment and several contextual considerations. No randomised trials were identified for these interventions in COVID-19, SARS, or MERS." (4) 1: https://www.nature.com/articles/s41591-020-0843-2 https://www.nature.com/articles/s41591-020-0843-2 2: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30162-6/fulltext https://www.thelancet.com/journals/laninf/article/PIIS1473-3... 3: https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818 https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818 4: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31142-9/fulltext https://www.thelancet.com/journals/lancet/article/PIIS0140-6...
smileypete 6y ago
>no, that's exactly the misunderstanding that leads to such security theater. distance does nearly all the work. a mask adds marginal benefit when distancing. FWIW... 'Yuen Kwok-yung, a professor of infectious disease at the University of Hong Kong, has advised his government that all social distancing can be relaxed – but only if people wear masks in enclosed spaces such as on trains and at work, and that no food or drink are consumed at concerts and cinemas.' https://www.theguardian.com/world/2020/may/22/why-we-might-not-get-a-coronavirus-vaccine https://www.theguardian.com/world/2020/may/22/why-we-might-n... (Yuen Kwok-yung is one of, if not the leading infectious disease specialist in Asia among other things, and has his name on many peer reviewed scientific papers.)
- clairity 6y ago
  that might seem contradictory, but not necessarily. the article doesn't provide enough information to draw a definitive conclusion, but it seems to imply the same order of things later in the article. so distancing as the primary mitigation, masks when you can't, as with trains, concerts, and cinemas (work depends on the office plan).