13 ms·

What we can learn from the latest indoor dining study

173 points by haltingproblem 6y ago

azepoi 6y ago
This is the open-access paper https://jkms.org/DOIx.php?id=10.3346/jkms.2020.35.e415 https://jkms.org/DOIx.php?id=10.3346/jkms.2020.35.e415
donatj 6y ago
Presumably both people in this noted illustration also touched the door handle, possibly the door itself, and any number of other surfaces while entering the building? I feel like drawing the link exclusively to air flow is tenuous at best. Saying with any level certainty that they didn't contract it _elsewhere_ seems dishonest.
- red0point 6y ago
  Well this is clearly stated in the paper. * Only the visitors (cases A and C) sitting in the air flow path of case B were infected with COVID-19, while other visitors (V2, V3) closer to the infector for a longer period of time but in the absence of direct air flow did not become infected. In addition, the visitors sitting at tables with cases A and C (V1, V6, and V7) were not infected with COVID-19 because they faced away from the infector’s face. These findings strongly suggest that this outbreak occurred by droplet transmission exceeding a 2 m distance and excluded contact and fomite transmission. This transmission pattern is similar with the outbreak of a restaurant with air conditioning in Guangzhou, China.21 In this article, the authors concluded that the most likely transmission was done by droplet and also emphasized the direction of air flow.* Also they analyzed the RNA to confirm linkage.
  - donatj 6y ago
    That quote does nothing to disprove surface based infection though. Some people are better at not touching their faces than others.
    - red0point 6y ago
      True, however it makes sense if you look at the figure they provide, which shows airflow and infections: https://jkms.org/ViewImage.php?Type=F&aid=694440&id=F3&afn=63_JKMS_35_46_e415&fn=jkms-35-e415-g003_0063JKMS https://jkms.org/ViewImage.php?Type=F&aid=694440&id=F3&afn=6... If it were contact based, this would mean that at least one other in the restaurant must have contracted it that was outside of the airflow path. Since this not the case, the most likely thing is that transmission was with the airflow. Why is it that you are so certain about this being surface based transmission?
  - zaroth 6y ago
    This lines up with other studies I’ve seen which show that contact and fomite transmission do not significantly drive transmission (that means hand washing and surface disinfecting won’t make much difference). Why would indoor dining be “safe”? Indoor anything is “unsafe”, as aerosolized transmission has been proven. Anything under a properly worn N95 doesn’t stop aerosols, and if anything will promote aerosols. The idea that wearing a mask from the time you walk in the door to the time you sit down is somehow affecting outcomes is insane. People should know that walking into a restaurant carries some risk of infection and a mask isn’t going to change that. 1. https://www.acpjournals.org/doi/full/10.7326/M20-5008 https://www.acpjournals.org/doi/full/10.7326/M20-5008
    - red0point 6y ago
      Do you have evidence to back up your claim that properly worn EN14683 IIR masks are not sufficient?
      - zaroth 6y ago
        How about because it says so on the label? > Type I, I R, II and II R face masks are medical masks tested in the direction of exhalation (inside to outside) and take into account the efficiency of bacterial filtration. Surgical masks of this type stop the wearer from infecting the surrounding environment. They are not effective at protecting the wearer from airbourne diseases such as coronavirus. > Type IIR face masks EN14683 are medical face masks made up of a 4 ply construction that prevents large particles from reaching the patient or working surfaces. Type IIR Face masks include a splash resistant layer to protect against blood and other bodily fluids. Type IIR face masks are tested in the direction of exhalation (inside to outside) and take into account the efficiency of bacterial filtration. They are not designed or tested to stop inhaling large droplets, nor exhaling small droplets. There is no scientific evidence they prevent the transmission of COVID and they specifically disclaim as much. However, properly worn FFP2, FFP3, N95 and other respirator masks are effective at protecting the wearer from viral transmission. That’s just not what most people are wearing outside a health care environment. And you can’t simply take them off when you sit down. First hit on Google: 1. https://www.dental-nursing.co.uk/news/covid-19-a-guide-to-face-masks https://www.dental-nursing.co.uk/news/covid-19-a-guide-to-fa...
- djent 6y ago
  Look at the time of arrival/departure for the customers. Case A arrived before Case B and Case A left before Case B left. On both sides of the door (or any other surface), Case A would have touched it before Case B. Despite this, Case B spread it to Case A.
  - donatj 6y ago
    Is there evidence though that asymptomatic Case C didn't leave before A and B arrived and gave it to both via a surface?
    - cfmcdonald 6y ago
      Yes, they tested everyone else in the restaurant and no one else was infected. If you are going to make specific critiques like this, you really need to read the article first.
JPKab 6y ago
On a strongly related note, are there any studies on outdoor transmission that are highly credible? I've long assumed that indoor dining is likely a transmission vector, but since LA recently banned outdoor dining, I'm curious about any studies on that. What I've been told is that LA did this with little scientific justification, and that outdoor transmission is rare. However, wondering what people on here more knowledgeable on the subject have found as far as peer reviewed research.
- GloriousKoji 6y ago
  The problem with "outdoor" dining was all the tents restaurants were setting up in fall/winter. And it's exactly as you imagine it, no airflow or sun exposure with the vinyl / canvas / plastic walls and roofs.
  - pdonis 6y ago
    > The problem with "outdoor" dining was all the tents restaurants were setting up in fall/winter. But not in LA, which was what the GP was asking about. LA's climate is fine for regular outdoor dining all year. > no airflow From the paper this thread is discussing, it appears that no airflow is actually lower risk; the higher risk is having directed airflow, from indoor ventilation systems, and being in the path of that airflow from an infected person (and also facing them).
    - natefox 6y ago
      Anecdotally, we've walking a few OC beach towns the last couple weeks.. its _all_ vinyl sided tents everywhere outside. They're keeping in the heat for evening dining. Afternoon dining is pretty easy to do, but dinner seems to be problematic even in OC where I'm at.
      - JPKab 6y ago
        Interesting thing to me is recirculated air vs. contained air. The vinyl sided tents aren't going to have recirculated air like indoors, but yes, the air is certainly not going to be flowing the way it would with no vinyl walls. OC beach towns are as nice as they are unaffordable, lol. I love the restaurants there, though.
mellosouls 6y ago
The tweeter has written up their observations here: https://zeynep.substack.com/p/small-data-big-implications https://zeynep.substack.com/p/small-data-big-implications
- haltingproblem 6y ago
  This is an incredible writeup and hard to summarize (compress) since there is so much good stuff in there. Give it a read and don't forget to subscribe to Zeynep's substack. I rarely find that reading her is not either educational or thought provoking. Her writing also is non-polarizing and has a refreshing quality to it.
  - mellosouls 6y ago
    I agree although I've only briefly skimmed through but Pocketed it immediately as it seemed top-notch in both content and coverage.
IronRanger 6y ago
Meanwhile in Sweden - 2020 deaths are tracking to be lower than 2018, 2017, and 2012: https://www.statista.com/statistics/525353/sweden-number-of-deaths/ https://www.statista.com/statistics/525353/sweden-number-of-... The spike in deaths seen earlier this year is similar to the 2009 flu epidemic: https://swprs.org/wp-content/uploads/2020/10/sweden-monthly-deaths-1851.jpg https://swprs.org/wp-content/uploads/2020/10/sweden-monthly-... Its unclear whether COVID presents a mortality burden any greater than regular influenza - and whether lockdowns or restrictions are at all warranted.
- deleted 6y ago
  [deleted]
- arrrg 6y ago
  Sweden has lots of restrictions in place. And had.
- nikolay 6y ago
  People have so many misconceptions about the measures in Sweden! Some are much stricter than elsewhere!
  - ttoinou 6y ago
    Please elaborate ! :)
    - nikolay 6y ago
      Everybody believes there are no restrictions at all and people carry on with their lives just like did before. Nobody talks about group gathering limits (smaller size than in most countries), that restaurants service hot food with much better safety than here in the States, etc. People still believe that Sweden's strategy is herd immunity without any interventions!
      - ttoinou 6y ago
        What interventions ? Small groups isn't that big of a restriction if you compare to others countries, and it only came very recently
dang 6y ago
Url changed from https://twitter.com/zeynep/status/1334641685154902021 https://twitter.com/zeynep/status/1334641685154902021, which points to this.
mortenjorck 6y ago
There's a number of sources on pandemic research that I consider authoritative, but none I've come to trust to the degree that I do Zeynep Tufekci. She's been the most rational, thoughtful, and proven voice on this since the beginning, and I consider her compiling, editing, and meta-analysis to be the gold standard.
- deleted 6y ago
  [deleted]
btilly 6y ago
Another astonishing fact is that airplane travel is surprisingly safe. https://www.scientificamerican.com/article/evaluating-covid-risk-on-planes-trains-and-automobiles2/ https://www.scientificamerican.com/article/evaluating-covid-...
- Johnny555 6y ago
  note that they only evaluated the airplane itself, not the airport or transportation to the airport. "Being in a crowded airport or taking a taxi to get there could be a bigger concern, though." I'm still not flying no matter how safe I am once I am seated on the plane.
  - schoolornot 6y ago
    Tens of thousands of people having to drop their masks in the same exact spots in airpots for TSA (USA) identification.
- vondur 6y ago
  Don't airplanes have pretty good air circulation/filtration going on? That would seem to explain this.
aphextron 6y ago
You have to think of it like cigarette smoke. Aerosolized virus particles linger, and fill a room. If someone is close enough to you that you would smell them smoking a cigarette, they are close enough to infect you. It's why "social distancing" is just meaningless safety theater in an indoors setting.
- djrogers 6y ago
  That’s really not at all what these studies show. It’s direct airflow, over short periods of time. Your smoke theory would have everyone in both restaurants infected, which is not what happened.
  - aphextron 6y ago
    >Your smoke theory would have everyone in both restaurants infected, which is not what happened. Not everyone who's exposed gets infected, and most of those who do remain entirely asymptomatic. But some die. That's why this thing is so dangerous to the population as a whole. There's endless amounts of computational fluid dynamics research being done on this. It's pretty clear that the virus particles are suspended in the air like smoke [0]. [0] https://www.sciencedirect.com/science/article/pii/S0925753520302630#p0175 https://www.sciencedirect.com/science/article/pii/S092575352...
  - lucb1e 6y ago
    I think it's a close enough analog. If there is sufficient ventilation, you might not smell it in one area but very strongly in another. If you place an infectious person in place of the smoker, you can guess where the danger zone is (not in the area free of smell). You're right, of course, that cigarette smoke carries further and many more people will be able to smell it than there are people at risk of infection in the same situation.
djrogers 6y ago
“We should follow Japan’s lead and discourage talking” As an introvert, I like this conclusion regardless of how it was arrived at.
- free2OSS 6y ago
  I read that Japan is doing well because they use kn95 masks. It baffles me we haven't been giving these away to old and obese people.
commonturtle 6y ago
I don't know why we're so hesitant to just close bars and restaurants everywhere, pay the staff generously, and leave the rest of the economy open. At least in the UK I think it would have stopped us from having a second lockdown.
- matz1 6y ago
  Close for what? The lockdown is not needed in the first place. The case number may be high but the case number is not useful because it doesn't tell if a person actually sick.
- ntsplnkv2 6y ago
  Because no one wants to pay them - it's the age old problem.
- 1123581321 6y ago
  The hesitancy is due to the cost and the desire some restaurants and some of their customers have for them to remain open. This is especially the case in non-island nations that cannot control their borders as easily.
- CincinnatiMan 6y ago
  Interesting thought. How much would that cost? And is it only restaurant direct staff that is compensated or also other industries that are negatively impacted by their closure?
- FuckButtons 6y ago
  There's an inherent tension, on the one hand, we cant afford to pay the wages of a 100 billion pound a year industry out of tax revenue. On the other hand we completely fucked up any of the potential ways we could have avoided doing that.
  - r00fus 6y ago
    Why can’t we pay them?
- 6y ago
stygiansonic 6y ago
For those wondering, the term "shoe-leather epidemiology" typically means work in the field undertaken as an immediate response to an outbreak: https://academic.oup.com/aje/article/172/6/737/99608 https://academic.oup.com/aje/article/172/6/737/99608
Evgeniuz 6y ago
I find it amusing that there are just two mentions of COVID-19 in the small quote in the middle of article. Yet everyone completely understands what this article is about. Wondering how soon it won't be so obvious (probably not very soon, but still).
cle 6y ago
> One, small data can be extremely illuminating. I love this. I think we dismiss "small data" too quickly. I see this all the time here on HN and in other places, where someone's experience will be dismissed as "just anecdotes", as if an anecdote contains no useful information at all. Statistical summaries by definition lose information--it can be incredibly valuable to continuously ask ourselves over time "What information is important to retain in our models/statistics, and what information is okay to discard?" To me, it seems obvious when I say it--well duh that's the scientific method--but it's so easy to become attached to our models and statistics and use those to dismiss important information as noise.
- wenc 6y ago
  Well, it seems to me that it's not so much the size of the data that really matters -- it's whether the amount of data and the method of collection is appropriate to the question at hand. Certain questions only require small samples to answer. If you frame your null hypothesis as "the virus is aerosol therefore everyone in an indoor space has equal probability of being infected after a period of time", then a few counterexamples is all that is necessary to reject the hypothesis. In the classic black swan example "all swans are white", it only took 1 counterexample (small data) to disprove the premise, while mountains of examples of white swans (big data) would be insufficient evidence to actually prove it. There's an asymmetry here. Coming back to the article, the author recognized this exact asymmetry in the question at hand: "While some of this may look discouraging, I find these “small data” studies greatly empowering. They don’t just tell us what happened, they tell us what didn’t happen." "These small studies cannot tell us the proportion of transmission that occurs indoors, but they highlight how it occurs: droplets and aerosols being carried through the air. Clearly, the closer you are to the person, the more likely you are to get hit But equally clearly, air flow and the positioning of people are huge variables, too. Just talking doesn’t seem to generate aerosols to the point that everyone within the room is infected (though this is possible), but singing does—at least in these well-studied cases. Sometimes, though, the most important information is that the dog did not bark." However, not all questions have this property. Let's say your hypothesis was something like "this vaccine will work in at least 95% of the population", small data approaches might not work. Bob and Jill said it worked for them -- how comfortable would we be extrapolating this anecdotal evidence to the general population? At most we can say there's a statistical signal to the affirmative, but nothing more than that. And that is the nature of self-reported anecdotal evidence (unless they were rigorously structured to remove confounding factors -- usually they are not). p.s. Furthermore, not all questions require rigor, therefore anecdotal evidence can sometimes be useful without being rigorous. For instance I've always found Myers Briggs to be a "useful" heuristic despite not having any rigorous basis.
free2OSS 6y ago
The whole opening bars/restaurants/casinos but closing gyms is mind boggling. I understand keeping the population subdued with circuses, but you'd think politicians would realize the gym is a positive outlet that will reduce coronavirus deaths by having a healthy population. My gym group broke up and 1 guy became overweight. Went from a no risk Coronavirus to high risk because Politicians messed up his routine.
- genericone 6y ago
  Gyms are where there is the most aggressive breathing and grunting though, and that volatalizes as much contagion as people singing. Restaurants are a calmer more subdued breathing environment.
  - phonypc 6y ago
    >Restaurants are a calmer more subdued breathing environment. Depends on the restaurant. Alcohol and loud music lead to raised voices and presumably greater transmission.
  - free2OSS 6y ago
    So what? Kn95 mask it up. Your gym population isn't going to clog up hospitals. And we need to kill this myth that every old person lives with their kid. Terrible Unscientific policy is causing more damage than if we did nothing.
DrScump 6y ago
Do any of these papers determine the exact transmission vector? (Air to eye, air to nose, air to mouth, hands/fingers to eye/nose/mouth, etc.)?

This is the open-access paper https://jkms.org/DOIx.php?id=10.3346/jkms.2020.35.e415 https://jkms.org/DOIx.php?id=10.3346/jkms.2020.35.e415

donatj 6y ago

Presumably both people in this noted illustration also touched the door handle, possibly the door itself, and any number of other surfaces while entering the building? I feel like drawing the link exclusively to air flow is tenuous at best. Saying with any level certainty that they didn't contract it _elsewhere_ seems dishonest.

red0point 6y ago
Well this is clearly stated in the paper. * Only the visitors (cases A and C) sitting in the air flow path of case B were infected with COVID-19, while other visitors (V2, V3) closer to the infector for a longer period of time but in the absence of direct air flow did not become infected. In addition, the visitors sitting at tables with cases A and C (V1, V6, and V7) were not infected with COVID-19 because they faced away from the infector’s face. These findings strongly suggest that this outbreak occurred by droplet transmission exceeding a 2 m distance and excluded contact and fomite transmission. This transmission pattern is similar with the outbreak of a restaurant with air conditioning in Guangzhou, China.21 In this article, the authors concluded that the most likely transmission was done by droplet and also emphasized the direction of air flow.* Also they analyzed the RNA to confirm linkage.
- donatj 6y ago
  That quote does nothing to disprove surface based infection though. Some people are better at not touching their faces than others.
  - red0point 6y ago
    True, however it makes sense if you look at the figure they provide, which shows airflow and infections: https://jkms.org/ViewImage.php?Type=F&aid=694440&id=F3&afn=63_JKMS_35_46_e415&fn=jkms-35-e415-g003_0063JKMS https://jkms.org/ViewImage.php?Type=F&aid=694440&id=F3&afn=6... If it were contact based, this would mean that at least one other in the restaurant must have contracted it that was outside of the airflow path. Since this not the case, the most likely thing is that transmission was with the airflow. Why is it that you are so certain about this being surface based transmission?
- zaroth 6y ago
  This lines up with other studies I’ve seen which show that contact and fomite transmission do not significantly drive transmission (that means hand washing and surface disinfecting won’t make much difference). Why would indoor dining be “safe”? Indoor anything is “unsafe”, as aerosolized transmission has been proven. Anything under a properly worn N95 doesn’t stop aerosols, and if anything will promote aerosols. The idea that wearing a mask from the time you walk in the door to the time you sit down is somehow affecting outcomes is insane. People should know that walking into a restaurant carries some risk of infection and a mask isn’t going to change that. 1. https://www.acpjournals.org/doi/full/10.7326/M20-5008 https://www.acpjournals.org/doi/full/10.7326/M20-5008
  - red0point 6y ago
    Do you have evidence to back up your claim that properly worn EN14683 IIR masks are not sufficient?
    - zaroth 6y ago
      How about because it says so on the label? > Type I, I R, II and II R face masks are medical masks tested in the direction of exhalation (inside to outside) and take into account the efficiency of bacterial filtration. Surgical masks of this type stop the wearer from infecting the surrounding environment. They are not effective at protecting the wearer from airbourne diseases such as coronavirus. > Type IIR face masks EN14683 are medical face masks made up of a 4 ply construction that prevents large particles from reaching the patient or working surfaces. Type IIR Face masks include a splash resistant layer to protect against blood and other bodily fluids. Type IIR face masks are tested in the direction of exhalation (inside to outside) and take into account the efficiency of bacterial filtration. They are not designed or tested to stop inhaling large droplets, nor exhaling small droplets. There is no scientific evidence they prevent the transmission of COVID and they specifically disclaim as much. However, properly worn FFP2, FFP3, N95 and other respirator masks are effective at protecting the wearer from viral transmission. That’s just not what most people are wearing outside a health care environment. And you can’t simply take them off when you sit down. First hit on Google: 1. https://www.dental-nursing.co.uk/news/covid-19-a-guide-to-face-masks https://www.dental-nursing.co.uk/news/covid-19-a-guide-to-fa...
djent 6y ago
Look at the time of arrival/departure for the customers. Case A arrived before Case B and Case A left before Case B left. On both sides of the door (or any other surface), Case A would have touched it before Case B. Despite this, Case B spread it to Case A.
- donatj 6y ago
  Is there evidence though that asymptomatic Case C didn't leave before A and B arrived and gave it to both via a surface?
  - cfmcdonald 6y ago
    Yes, they tested everyone else in the restaurant and no one else was infected. If you are going to make specific critiques like this, you really need to read the article first.

JPKab 6y ago

On a strongly related note, are there any studies on outdoor transmission that are highly credible? I've long assumed that indoor dining is likely a transmission vector, but since LA recently banned outdoor dining, I'm curious about any studies on that. What I've been told is that LA did this with little scientific justification, and that outdoor transmission is rare. However, wondering what people on here more knowledgeable on the subject have found as far as peer reviewed research.

GloriousKoji 6y ago
The problem with "outdoor" dining was all the tents restaurants were setting up in fall/winter. And it's exactly as you imagine it, no airflow or sun exposure with the vinyl / canvas / plastic walls and roofs.
- pdonis 6y ago
  > The problem with "outdoor" dining was all the tents restaurants were setting up in fall/winter. But not in LA, which was what the GP was asking about. LA's climate is fine for regular outdoor dining all year. > no airflow From the paper this thread is discussing, it appears that no airflow is actually lower risk; the higher risk is having directed airflow, from indoor ventilation systems, and being in the path of that airflow from an infected person (and also facing them).
  - natefox 6y ago
    Anecdotally, we've walking a few OC beach towns the last couple weeks.. its _all_ vinyl sided tents everywhere outside. They're keeping in the heat for evening dining. Afternoon dining is pretty easy to do, but dinner seems to be problematic even in OC where I'm at.
    - JPKab 6y ago
      Interesting thing to me is recirculated air vs. contained air. The vinyl sided tents aren't going to have recirculated air like indoors, but yes, the air is certainly not going to be flowing the way it would with no vinyl walls. OC beach towns are as nice as they are unaffordable, lol. I love the restaurants there, though.

mellosouls 6y ago

The tweeter has written up their observations here: https://zeynep.substack.com/p/small-data-big-implications https://zeynep.substack.com/p/small-data-big-implications

haltingproblem 6y ago
This is an incredible writeup and hard to summarize (compress) since there is so much good stuff in there. Give it a read and don't forget to subscribe to Zeynep's substack. I rarely find that reading her is not either educational or thought provoking. Her writing also is non-polarizing and has a refreshing quality to it.
- mellosouls 6y ago
  I agree although I've only briefly skimmed through but Pocketed it immediately as it seemed top-notch in both content and coverage.

IronRanger 6y ago

Meanwhile in Sweden - 2020 deaths are tracking to be lower than 2018, 2017, and 2012: https://www.statista.com/statistics/525353/sweden-number-of-deaths/ https://www.statista.com/statistics/525353/sweden-number-of-... The spike in deaths seen earlier this year is similar to the 2009 flu epidemic: https://swprs.org/wp-content/uploads/2020/10/sweden-monthly-deaths-1851.jpg https://swprs.org/wp-content/uploads/2020/10/sweden-monthly-... Its unclear whether COVID presents a mortality burden any greater than regular influenza - and whether lockdowns or restrictions are at all warranted.

deleted 6y ago
[deleted]
arrrg 6y ago
Sweden has lots of restrictions in place. And had.
nikolay 6y ago
People have so many misconceptions about the measures in Sweden! Some are much stricter than elsewhere!
- ttoinou 6y ago
  Please elaborate ! :)
  - nikolay 6y ago
    Everybody believes there are no restrictions at all and people carry on with their lives just like did before. Nobody talks about group gathering limits (smaller size than in most countries), that restaurants service hot food with much better safety than here in the States, etc. People still believe that Sweden's strategy is herd immunity without any interventions!
    - ttoinou 6y ago
      What interventions ? Small groups isn't that big of a restriction if you compare to others countries, and it only came very recently

dang 6y ago

Url changed from https://twitter.com/zeynep/status/1334641685154902021 https://twitter.com/zeynep/status/1334641685154902021, which points to this.

mortenjorck 6y ago

There's a number of sources on pandemic research that I consider authoritative, but none I've come to trust to the degree that I do Zeynep Tufekci. She's been the most rational, thoughtful, and proven voice on this since the beginning, and I consider her compiling, editing, and meta-analysis to be the gold standard.

deleted 6y ago
[deleted]

btilly 6y ago

Another astonishing fact is that airplane travel is surprisingly safe. https://www.scientificamerican.com/article/evaluating-covid-risk-on-planes-trains-and-automobiles2/ https://www.scientificamerican.com/article/evaluating-covid-...

Johnny555 6y ago
note that they only evaluated the airplane itself, not the airport or transportation to the airport. "Being in a crowded airport or taking a taxi to get there could be a bigger concern, though." I'm still not flying no matter how safe I am once I am seated on the plane.
- schoolornot 6y ago
  Tens of thousands of people having to drop their masks in the same exact spots in airpots for TSA (USA) identification.
vondur 6y ago
Don't airplanes have pretty good air circulation/filtration going on? That would seem to explain this.

aphextron 6y ago

You have to think of it like cigarette smoke. Aerosolized virus particles linger, and fill a room. If someone is close enough to you that you would smell them smoking a cigarette, they are close enough to infect you. It's why "social distancing" is just meaningless safety theater in an indoors setting.

djrogers 6y ago
That’s really not at all what these studies show. It’s direct airflow, over short periods of time. Your smoke theory would have everyone in both restaurants infected, which is not what happened.
- aphextron 6y ago
  >Your smoke theory would have everyone in both restaurants infected, which is not what happened. Not everyone who's exposed gets infected, and most of those who do remain entirely asymptomatic. But some die. That's why this thing is so dangerous to the population as a whole. There's endless amounts of computational fluid dynamics research being done on this. It's pretty clear that the virus particles are suspended in the air like smoke [0]. [0] https://www.sciencedirect.com/science/article/pii/S0925753520302630#p0175 https://www.sciencedirect.com/science/article/pii/S092575352...
- lucb1e 6y ago
  I think it's a close enough analog. If there is sufficient ventilation, you might not smell it in one area but very strongly in another. If you place an infectious person in place of the smoker, you can guess where the danger zone is (not in the area free of smell). You're right, of course, that cigarette smoke carries further and many more people will be able to smell it than there are people at risk of infection in the same situation.

djrogers 6y ago

“We should follow Japan’s lead and discourage talking” As an introvert, I like this conclusion regardless of how it was arrived at.

free2OSS 6y ago
I read that Japan is doing well because they use kn95 masks. It baffles me we haven't been giving these away to old and obese people.

commonturtle 6y ago

I don't know why we're so hesitant to just close bars and restaurants everywhere, pay the staff generously, and leave the rest of the economy open. At least in the UK I think it would have stopped us from having a second lockdown.

matz1 6y ago
Close for what? The lockdown is not needed in the first place. The case number may be high but the case number is not useful because it doesn't tell if a person actually sick.
ntsplnkv2 6y ago
Because no one wants to pay them - it's the age old problem.
1123581321 6y ago
The hesitancy is due to the cost and the desire some restaurants and some of their customers have for them to remain open. This is especially the case in non-island nations that cannot control their borders as easily.
CincinnatiMan 6y ago
Interesting thought. How much would that cost? And is it only restaurant direct staff that is compensated or also other industries that are negatively impacted by their closure?
FuckButtons 6y ago
There's an inherent tension, on the one hand, we cant afford to pay the wages of a 100 billion pound a year industry out of tax revenue. On the other hand we completely fucked up any of the potential ways we could have avoided doing that.
- r00fus 6y ago
  Why can’t we pay them?
6y ago

stygiansonic 6y ago

For those wondering, the term "shoe-leather epidemiology" typically means work in the field undertaken as an immediate response to an outbreak: https://academic.oup.com/aje/article/172/6/737/99608 https://academic.oup.com/aje/article/172/6/737/99608

Evgeniuz 6y ago

I find it amusing that there are just two mentions of COVID-19 in the small quote in the middle of article. Yet everyone completely understands what this article is about. Wondering how soon it won't be so obvious (probably not very soon, but still).

cle 6y ago

> One, small data can be extremely illuminating. I love this. I think we dismiss "small data" too quickly. I see this all the time here on HN and in other places, where someone's experience will be dismissed as "just anecdotes", as if an anecdote contains no useful information at all. Statistical summaries by definition lose information--it can be incredibly valuable to continuously ask ourselves over time "What information is important to retain in our models/statistics, and what information is okay to discard?" To me, it seems obvious when I say it--well duh that's the scientific method--but it's so easy to become attached to our models and statistics and use those to dismiss important information as noise.

wenc 6y ago
Well, it seems to me that it's not so much the size of the data that really matters -- it's whether the amount of data and the method of collection is appropriate to the question at hand. Certain questions only require small samples to answer. If you frame your null hypothesis as "the virus is aerosol therefore everyone in an indoor space has equal probability of being infected after a period of time", then a few counterexamples is all that is necessary to reject the hypothesis. In the classic black swan example "all swans are white", it only took 1 counterexample (small data) to disprove the premise, while mountains of examples of white swans (big data) would be insufficient evidence to actually prove it. There's an asymmetry here. Coming back to the article, the author recognized this exact asymmetry in the question at hand: "While some of this may look discouraging, I find these “small data” studies greatly empowering. They don’t just tell us what happened, they tell us what didn’t happen." "These small studies cannot tell us the proportion of transmission that occurs indoors, but they highlight how it occurs: droplets and aerosols being carried through the air. Clearly, the closer you are to the person, the more likely you are to get hit But equally clearly, air flow and the positioning of people are huge variables, too. Just talking doesn’t seem to generate aerosols to the point that everyone within the room is infected (though this is possible), but singing does—at least in these well-studied cases. Sometimes, though, the most important information is that the dog did not bark." However, not all questions have this property. Let's say your hypothesis was something like "this vaccine will work in at least 95% of the population", small data approaches might not work. Bob and Jill said it worked for them -- how comfortable would we be extrapolating this anecdotal evidence to the general population? At most we can say there's a statistical signal to the affirmative, but nothing more than that. And that is the nature of self-reported anecdotal evidence (unless they were rigorously structured to remove confounding factors -- usually they are not). p.s. Furthermore, not all questions require rigor, therefore anecdotal evidence can sometimes be useful without being rigorous. For instance I've always found Myers Briggs to be a "useful" heuristic despite not having any rigorous basis.

free2OSS 6y ago

The whole opening bars/restaurants/casinos but closing gyms is mind boggling. I understand keeping the population subdued with circuses, but you'd think politicians would realize the gym is a positive outlet that will reduce coronavirus deaths by having a healthy population. My gym group broke up and 1 guy became overweight. Went from a no risk Coronavirus to high risk because Politicians messed up his routine.

genericone 6y ago
Gyms are where there is the most aggressive breathing and grunting though, and that volatalizes as much contagion as people singing. Restaurants are a calmer more subdued breathing environment.
- phonypc 6y ago
  >Restaurants are a calmer more subdued breathing environment. Depends on the restaurant. Alcohol and loud music lead to raised voices and presumably greater transmission.
- free2OSS 6y ago
  So what? Kn95 mask it up. Your gym population isn't going to clog up hospitals. And we need to kill this myth that every old person lives with their kid. Terrible Unscientific policy is causing more damage than if we did nothing.

DrScump 6y ago

Do any of these papers determine the exact transmission vector? (Air to eye, air to nose, air to mouth, hands/fingers to eye/nose/mouth, etc.)?