Covid-19 Superspreader Events in 28 Countries: Critical Patterns and Lessons(quillette.com)
quillette.com
Covid-19 Superspreader Events in 28 Countries: Critical Patterns and Lessons
https://quillette.com/2020/04/23/covid-19-superspreader-events-in-28-countries-critical-patterns-and-lessons/
152 comments
Wait a minute.
> But the researchers instead found evidence for the opposite: “The key factor for infection was the direction of the airflow,” with downstream individuals being most at risk—a result consistent with the thesis that COVID-19 is transmitted primarily through the ballistic transmission of large respiratory droplets.
If the direction of airflow is the key factor, then the droplets have to be moving with the airflow, and therefore not ballistic.
Am I missing something?
> But the researchers instead found evidence for the opposite: “The key factor for infection was the direction of the airflow,” with downstream individuals being most at risk—a result consistent with the thesis that COVID-19 is transmitted primarily through the ballistic transmission of large respiratory droplets.
If the direction of airflow is the key factor, then the droplets have to be moving with the airflow, and therefore not ballistic.
Am I missing something?
I believe the reasoning is that aerosol would have ultimately spread everywhere, including on the AC itself, while ballistics can be heavily influenced by airflow, but are still limited in range.
[deleted]
I think the definition of ballistic means that gravity is the dominant force governing its path through space. So if it is "heavily influenced" by airflow it is by definition not ballistic.
Then again, it's not aerosolized as it didn't diffuse homogenously into the space. It's somewhere in between.
Then again, it's not aerosolized as it didn't diffuse homogenously into the space. It's somewhere in between.
Eh, different fields can have different definitions for the same word, and that's okay. If I tell a chemist that carbon is a metal, I would get a funny look. If I tell an astrophysicist that carbon is a metal, it is perfectly reasonable. Within the field of astronomy, metals are any element other than hydrogen and helium. There may be a similar difference in definitions here
For those who are curious, you can read more here: https://en.wikipedia.org/wiki/Metallicity
You've really got three regimes. Really big things are ballistic in your sense that the dominant force is gravity. Smaller things are also sensitive to bulk air movement. Really small things aren't affected much by gravity, and brownian motion is more important.
When these guys are saying "ballistic", they mean that the droplet is big enough that gravity is important, and that it's going to hit the ground in a reasonable amount of time and not hang around in the air until convection/diffusion spread it evenly throughout the room.
When these guys are saying "ballistic", they mean that the droplet is big enough that gravity is important, and that it's going to hit the ground in a reasonable amount of time and not hang around in the air until convection/diffusion spread it evenly throughout the room.
[deleted]
Yeah, this explanation was messed up. Also, if you look at the graphic associated with this, it seems like people both upstream and downstream of the individual were infected and it is not clear if some of them had the infection simultaneously or were actually infected by the first person. Lots of questions here.
speaking of ballistics. i wonder, is there an easy way to increase the surface tension on these droplets? Maybe an inhaler or something that makes these droplets large and fall to the ground faster?
That's almost exactly the description of a scene from the 90s movie "Outbreak" where Dustin Hoffman follows a vent in a hospital to learn that the virus is airborne.
Might even be where they got the idea.
So droplet size is very important for spreading then, implies wearing a mask will be quite effective at preventing you from contaminating other people...
"Three of the SSEs—in Japan, Skagit County, WA, and Singapore—involved concert-goers and singing groups belting out tunes together over a period of hours. (The Skagit example is particularly interesting, because the organizers were aware of the COVID-19 risk beforehand, and took the precaution of spacing out the participants by several feet. If they had been merely chatting, instead of singing, no one might have gotten sick.)"
Imagine how bad Austin would have been if SXSW had actually gone ahead given how hellbent they were on going through with it. It would have been much much worse state than it is now. It is a positive that the government listened to health officials and shut it all down despite the complaining to the contrary. Economies never work well in sickened environments.
Imagine how bad Austin would have been if SXSW had actually gone ahead given how hellbent they were on going through with it. It would have been much much worse state than it is now. It is a positive that the government listened to health officials and shut it all down despite the complaining to the contrary. Economies never work well in sickened environments.
But the article goes on to say that "common human activity that aren’t represented among these listed SSEs: watching movies in a theater, being on a train or bus, attending theater, opera, or symphony"
But what I found interesting about the article (and it is long read) is his hypotheses on mode of transmission. Which is the "direct ballistic delivery of a large-droplet Flüggian payload from face A to face B" and that means that interventions like the "expanded use of masks and social distancing is critical" And we should also speak softly, avoid “coughing, blowing and sneezing,” or exhibiting any kind of agitated respiratory state in public, and angle their mouths downward when speaking."
But he does warn that he is a Computer Scientist rather than having any medical background.
But what I found interesting about the article (and it is long read) is his hypotheses on mode of transmission. Which is the "direct ballistic delivery of a large-droplet Flüggian payload from face A to face B" and that means that interventions like the "expanded use of masks and social distancing is critical" And we should also speak softly, avoid “coughing, blowing and sneezing,” or exhibiting any kind of agitated respiratory state in public, and angle their mouths downward when speaking."
But he does warn that he is a Computer Scientist rather than having any medical background.
The author seems to ignore the obvious confounding factor here of selection bias -- super spreader events all seem to deal with people who are in the same social circles rather than outside them, as would be the case in public transportation, movie theaters, gyms, etc. The reason being that events with people in social socials are readily traceable to an infected individual attending, whereas contact tracing for anonymous infection in a shared area is much more difficult.
Even diseases with low transmissibility are known to be disseminated by public transit, such as tuberculosis.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4338233/
Even diseases with low transmissibility are known to be disseminated by public transit, such as tuberculosis.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4338233/
I didn't get the sense that he was claiming any kind of authority, and he was pretty up front about selection bias. He wrote:
> I am not an epidemiologist, let alone a virologist. And the data I am working with is substandard anyway, as there are all sorts of obvious selection biases at play, including the editorial biases of the journalists on whom I rely for local reports.
> I am not an epidemiologist, let alone a virologist. And the data I am working with is substandard anyway, as there are all sorts of obvious selection biases at play, including the editorial biases of the journalists on whom I rely for local reports.
Adding a disclaimer like this to the middle rather than all the places in the article where they might be implying that SSEs only occur in certain documented situations is disingenuous at best and deliberately misleading at worst, in my opinion.
Is it really disingenuous at best? Like you think the best case scenario is that this guy is being insincere. I sincerely think this approach of just assuming bad faith is not useful.
"all the places in the article where they might be implying..." seems kinda over the top.
I think a better thing to do would be to refactor the disclaimer and put it at the top/start of the article.
I think a better thing to do would be to refactor the disclaimer and put it at the top/start of the article.
[deleted]
Interesting theory, why do you suppose a concert has more friends and less strangers at it than an opera or symphony?
The articles elaborate. In Japan and Singapore contract tracing is much easier,
Japan
> Less than two weeks later, she tested positive for the virus, and the authorities swiftly alerted others who had been at the club. As more infections soon emerged from three other music venues in the city, officials tested concertgoers and their close contacts, and urged others to stay home. All told, 106 cases were linked to the clubs, and nine people are still hospitalized.
Singapore
> Singapore's biggest cluster of Covid-19 patients, traced to a restaurant in Jurong, had more than just a dinner in common, said Ministry of Health director of medical services Kenneth Mak yesterday.
> "We've recognised that many of the individuals linked to this particular group of people getting infected had many common social activities," said Associate Professor Mak, pointing to other gatherings such as singing classes that infected individuals had taken part in together.
> "So, in fact, their social interactions went well beyond the dinner in that particular location, and as a result of those close activities... that's where the spread is actually occurring," he said.
Washington was at a choir, where everyone would have known each other
> Health officials said all 28 choir members who were tested for COVID-19 were found to be infected. The other 17 with symptoms never got tested, either because tests were not available or — like Comstock and Owen — the singers were under the impression that only people in dire condition were eligible.
Japan
> Less than two weeks later, she tested positive for the virus, and the authorities swiftly alerted others who had been at the club. As more infections soon emerged from three other music venues in the city, officials tested concertgoers and their close contacts, and urged others to stay home. All told, 106 cases were linked to the clubs, and nine people are still hospitalized.
Singapore
> Singapore's biggest cluster of Covid-19 patients, traced to a restaurant in Jurong, had more than just a dinner in common, said Ministry of Health director of medical services Kenneth Mak yesterday.
> "We've recognised that many of the individuals linked to this particular group of people getting infected had many common social activities," said Associate Professor Mak, pointing to other gatherings such as singing classes that infected individuals had taken part in together.
> "So, in fact, their social interactions went well beyond the dinner in that particular location, and as a result of those close activities... that's where the spread is actually occurring," he said.
Washington was at a choir, where everyone would have known each other
> Health officials said all 28 choir members who were tested for COVID-19 were found to be infected. The other 17 with symptoms never got tested, either because tests were not available or — like Comstock and Owen — the singers were under the impression that only people in dire condition were eligible.
I think more importantly, it's much easier to pull a list of people attending a particular concert or other ticketed mass gathering, compared to getting a recursive enumeration of people whose paths intersected with any of a set of suspected people on mass transit during the course of a couple of days.
Well, I'd say there's a big difference between sitting silently in chairs at an opera or symphony and standing/moshing/yelling loudly in extremely crowded quarters at a rock concert.
I get that, and the comment I was replying to was specifically refuting the "ballistic droplets" theory in favor of a "confounding variable" of them just happening to be in the same social circles.
A lot of coughing and high risk individuals at the symphony though, unfortunately.
High risk for mortality, yes. But are they higher risk for actually catching the bug when exposed? I don't think anyone knows that.
I'm not even sure how you could come up with numbers on how much viral exposure is needed to infect someone, short of controlled experiments with volunteers. The odds of killing a few volunteers seems pretty damn high, especially if you are testing with more vulnerable folks to establish a differential estimate. That's not a study I'd want to be involved in on either side of the clipboard.
I'm not even sure how you could come up with numbers on how much viral exposure is needed to infect someone, short of controlled experiments with volunteers. The odds of killing a few volunteers seems pretty damn high, especially if you are testing with more vulnerable folks to establish a differential estimate. That's not a study I'd want to be involved in on either side of the clipboard.
Just hypothesizing as well, but I think he might have it backwards. I'm not convinced you'll get magnitudes more virus in the ambient air from singing. But as a receiver if you're mouth breathing and taking deep breaths you're extra vulnerable. Nose hair is pretty effective
If the conductor wants you to make the consonants clear, then there will be spittle. Agreed that the deep breathing is likely just as important.
>or exhibiting any kind of agitated respiratory state in public
The only sizable population of people that I still see out in public that aren't wearing masks are joggers. I wonder if and when we will put a stop to that.
The only sizable population of people that I still see out in public that aren't wearing masks are joggers. I wonder if and when we will put a stop to that.
This would also explain why many people are asymptomatic. They are still getting exposed but with a much lower viral load. Maybe the best "vaccine" here is just the lowest possible microdose of the coronavirus. We really should be looking at all the asymptomatic or low symptoms folks and figuring out what they have in common with one another. I would bet you it's just very low exposure, which gives the body more time to develop antibodies and mount a defense instead of the immune system being overwhelmed before it can adequately develop antibodies.
> If they had been merely chatting, instead of singing, no one might have gotten sick.
Really??
Really??
It's entirely possible. Heavier breathing expels more droplets, and further.
It also requires deeper inhalation by the receiver.
I think one of the things people over-estimate is how much evidence is used in making public health decisions.
The UKs advice is to wash hands but not to use a face mask. Hand washing is essentially free but the cost of producing reusable cotton face masks for every single person would likely be ~ £1 billion. If that is money wasted, it is still extremely small compared to the economic devastation which could cost the UK government ~ £100 billion [1] and the economy as a whole significantly more
[1] https://obr.uk/coronavirus-reference-scenario/
The UKs advice is to wash hands but not to use a face mask. Hand washing is essentially free but the cost of producing reusable cotton face masks for every single person would likely be ~ £1 billion. If that is money wasted, it is still extremely small compared to the economic devastation which could cost the UK government ~ £100 billion [1] and the economy as a whole significantly more
[1] https://obr.uk/coronavirus-reference-scenario/
I think the reticence to promote masks is that there's not enough of them. It's getting better, but if a month ago they had said "everyone has to wear a mask" it would have been a panic as people can't get hold of them, plus it would have been harder to get some for essential workers.
If there had been massive stockpiles available, the message would have likely been different.
If there had been massive stockpiles available, the message would have likely been different.
The general evidence for washing hands as an effective counter-measure is very very strong. It is a complete no-brainer, while decisions regarding face masks are complex and have to take into account lots of variables.
Can you point to evidence to back up your claim that "The general evidence for washing hands as an effective counter-measure is very very strong."
Meta-studies show that the effectiveness of hand washing alone is minimal https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4891197/
Meta-studies show that the effectiveness of hand washing alone is minimal https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4891197/
I think you misread me, I meant "general" as in general counter-measure, not COVID19-specific. Clearly I should have been more precise. In a situation where overload of healthcare is a primary concern, recommending counter-measures against general infections (where hand hygiene qualifies) is a no-brainer.
I'd been wondering why crowded public transport where people are breathing right next to one another hasn't caused massive spreading. This explanation makes a lot of sense - only when we cough or have to speak loudly do we exhale a significant amount of droplets.
People tend to believe this virus is vastly more contagious than other airborne illnesses. It's certainly more contagious than the flu, by all accounts so far, but it's not even close to as contagious as measles. Simply walking by or standing next to an infected person almost certainly won't get you infected, unless they are actually coughing and sneezing in an indoor space (or directly at you).
To be clear, it's not airborne. Measles is so contagious because it's airborne; SARS-CoV-2 is spread via droplets that fall to the ground fairly rapidly. It's a technical distinction, but an important one.
https://www.who.int/news-room/commentaries/detail/modes-of-t...
> In an analysis of 75,465 COVID-19 cases in China, airborne transmission was not reported.
(This is also a reason masks can be effective despite the virus particles being smaller than what masks can stop; you don't have to stop the particles, but the much larger drops they're contained within.)
https://www.who.int/news-room/commentaries/detail/modes-of-t...
> In an analysis of 75,465 COVID-19 cases in China, airborne transmission was not reported.
(This is also a reason masks can be effective despite the virus particles being smaller than what masks can stop; you don't have to stop the particles, but the much larger drops they're contained within.)
Also, many filters actually can stop smaller particles than you might expect based on the rating. Most people think of a filter as working the way a net does. There is a gap size between the fibers, and anything smaller than that gets through easily, and anything larger does not.
It's more complicated because there are actually 4 mechanisms that might stop a particle from getting through.
1. For particles bigger than the gaps, it does work like a net as most people expect.
2. For particular smaller than that but massive enough that they cannot change direction fast enough to follow the air stream they can miss turns of the air flow and get embedded in the fibers.
3. For even smaller particles they can get jostled around significantly by hits from gas molecules (like with Brownian motion). This can knock them into fibers where they can become embedded.
4. Some filters materials have an electrostatic effect that can attract and hold passing particles.
One of the reasons filters are commonly rated by their efficiency at 0.3 micron is that this is in the region where the filter is least efficient. For bigger particles, the gains from #2 and later #1 more than make up for #3 being irrelevant at those sizes. For smaller particular, the gains from #3 increase efficiency.
So you have the filter roughly getting worse down to the 0.3 micron ballpark, and then getting better as particles become still smaller, and at some point as you continue getting smaller it is going to get worse again. (I don't know where that final turn around is).
It's more complicated because there are actually 4 mechanisms that might stop a particle from getting through.
1. For particles bigger than the gaps, it does work like a net as most people expect.
2. For particular smaller than that but massive enough that they cannot change direction fast enough to follow the air stream they can miss turns of the air flow and get embedded in the fibers.
3. For even smaller particles they can get jostled around significantly by hits from gas molecules (like with Brownian motion). This can knock them into fibers where they can become embedded.
4. Some filters materials have an electrostatic effect that can attract and hold passing particles.
One of the reasons filters are commonly rated by their efficiency at 0.3 micron is that this is in the region where the filter is least efficient. For bigger particles, the gains from #2 and later #1 more than make up for #3 being irrelevant at those sizes. For smaller particular, the gains from #3 increase efficiency.
So you have the filter roughly getting worse down to the 0.3 micron ballpark, and then getting better as particles become still smaller, and at some point as you continue getting smaller it is going to get worse again. (I don't know where that final turn around is).
>To be clear, it's not airborne.
I understand the distinction, but the terminology should be renamed imho, to something like "epidemiologist airborne". Because to the layperson it definitely is transmitted "through the air", implying again in everyday terms "airborne transmission".
e.g. read this : https://wwwnc.cdc.gov/eid/article/26/7/20-0764_article
and look at the associated diagram:
https://wwwnc.cdc.gov/eid/article/26/7/20-0764-f1
Those people were NOT all within six feet of each other.
The German auto part plant paper also details transmission where nobody sneezed or coughed at a short business meeting.
I understand the distinction, but the terminology should be renamed imho, to something like "epidemiologist airborne". Because to the layperson it definitely is transmitted "through the air", implying again in everyday terms "airborne transmission".
e.g. read this : https://wwwnc.cdc.gov/eid/article/26/7/20-0764_article
and look at the associated diagram:
https://wwwnc.cdc.gov/eid/article/26/7/20-0764-f1
Those people were NOT all within six feet of each other.
The German auto part plant paper also details transmission where nobody sneezed or coughed at a short business meeting.
> Those people were NOT all within six feet of each other.
As that study discusses, they were in the path of an air conditioner. The "six feet" thing is a rough estimate, not the Eleventh Commandment.
As that study discusses, they were in the path of an air conditioner. The "six feet" thing is a rough estimate, not the Eleventh Commandment.
What makes you think that crowded public transport didn’t pay a role in NY’s prevalence being so high?
Public transit certainly didn't cause NYC-like levels of transmission in Japan, though it has a similarly dense public transit system.
Don’t riders almost universally wear masks on public transit in Japan?
Not sure why you're getting downvoted. Mask wearing percentages on public transit is quite different in NYC compared to Tokyo.
Not sure about universally, but certainly more commonly. Also, speaking loudly on trains is frowned upon. Speaking on your phone whilst on trains is not allowed.
They don't. Common etiquette there is to wear a mask when sick (they also wear them for allergies and warmth), but the majority (pre-covid) do not.
Coronovirus has an rFactor of 2-3 and it is airborne, which requires droplets from a host to come in contact with an uninfected person. But these droplets travel to the air and then will collect on a surface. They will not stay suspended in the air. Simply breathing next to a person who has the virus isn't enough for transmission.
By contrast, measles has an rFactor of 17, because it is an aerosol. It is 6x more contagious. And as an aeorsol, simply breathing next to a person who is infected is enough for you to contract the virus.
Airborne is not the same as aerosol.
Put another way. If there is a person infected in a house hold with coronavirus, not everyone is guaranteed to get it, because it is only airborne.
If someone has the measles in a house hold, and there is no vaccine, then everyone will get it, because it is an aerosol.
By contrast, measles has an rFactor of 17, because it is an aerosol. It is 6x more contagious. And as an aeorsol, simply breathing next to a person who is infected is enough for you to contract the virus.
Airborne is not the same as aerosol.
Put another way. If there is a person infected in a house hold with coronavirus, not everyone is guaranteed to get it, because it is only airborne.
If someone has the measles in a house hold, and there is no vaccine, then everyone will get it, because it is an aerosol.
https://www.who.int/news-room/commentaries/detail/modes-of-t...
> In an analysis of 75,465 COVID-19 cases in China, airborne transmission was not reported.
"They will not stay suspended in the air" means it's not airborne. An airborne disease is one that does stay suspended in the air.
> In an analysis of 75,465 COVID-19 cases in China, airborne transmission was not reported.
"They will not stay suspended in the air" means it's not airborne. An airborne disease is one that does stay suspended in the air.
You have the terminology backwards. Coronavirus is not (epidemiologically) airborne, but it can be aerosolized and transmit through the air.
> Coronovirus has an rFactor of 2-3
It's recently been revised up to 5-6 [0], and mortality estimates reduced.
https://www.forbes.com/sites/tarahaelle/2020/04/07/the-covid...
It's recently been revised up to 5-6 [0], and mortality estimates reduced.
https://www.forbes.com/sites/tarahaelle/2020/04/07/the-covid...
R0 is environment specific and this number should be taken with a grain of salt.
The CDC paper [1] estimated that the R0 value may have been 5-6 in Wuhan, during lunar new year, and before the public was ware of the virus.
Alternatively, the R0 value is now <1 in the US and the spread is decreasing,
https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article
The CDC paper [1] estimated that the R0 value may have been 5-6 in Wuhan, during lunar new year, and before the public was ware of the virus.
Alternatively, the R0 value is now <1 in the US and the spread is decreasing,
https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article
We don’t know the R0 in the US yet. We need widespread testing that we don’t have to evaluate it.
Evidence out of NY today says it’s possible 14% of the state has already been infected. That’d point to a pretty high value.
https://www.wxxinews.org/post/random-test-finds-nearly-14-ny...
Evidence out of NY today says it’s possible 14% of the state has already been infected. That’d point to a pretty high value.
https://www.wxxinews.org/post/random-test-finds-nearly-14-ny...
R0 is variable over time and describes the change in number of NEW cases.
IF new cases today are less than yesterday, the R0 must be <1 one incubation period ago. That doesn't mean that R0 wasn't different a month ago, or will be the same a month from now.
IF new cases today are less than yesterday, the R0 must be <1 one incubation period ago. That doesn't mean that R0 wasn't different a month ago, or will be the same a month from now.
> IF new cases today are less than yesterday
That's a big if. We don't have enough testing in place to determine that currently. The reported number of cases and the actual number of cases are not the same right now.
That's a big if. We don't have enough testing in place to determine that currently. The reported number of cases and the actual number of cases are not the same right now.
We certainly have enough information now. You don’t need to know the total number of infections to know the trend.
Positive cases have stayed roughly the same since April 4th while testing increased. For R0 to be greater than 1, we would have to be worse at testing.
Positive cases have stayed roughly the same since April 4th while testing increased. For R0 to be greater than 1, we would have to be worse at testing.
Testing has not increased. Look at the chart here:
https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/test...
(Direct link: https://www.cdc.gov/coronavirus/2019-ncov/images/lab-specime...)
We've been basically flat since mid-March.
https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/test...
(Direct link: https://www.cdc.gov/coronavirus/2019-ncov/images/lab-specime...)
We've been basically flat since mid-March.
Good point. I was mistaken.
I think the point still stands unless you think we are identifying a lower proportion of infections
I think the point still stands unless you think we are identifying a lower proportion of infections
> I think the point still stands unless you think we are identifying a lower proportion of infections
I do. https://www1.nyc.gov/assets/doh/downloads/pdf/imm/covid-19-d... indicates many areas of NYC are seeing more than 57% positive results; that likely indicates we're not even scratching the surface. We're simply not that good at identifying who to test.
I do. https://www1.nyc.gov/assets/doh/downloads/pdf/imm/covid-19-d... indicates many areas of NYC are seeing more than 57% positive results; that likely indicates we're not even scratching the surface. We're simply not that good at identifying who to test.
considering the cdc's history on this (no masks!), I'd take anything they say with a grain of salt.
The estimated r0 of 2/3 is hilarious. less contagious than sars eh? No amount of down-voting me or cdc papers is going to convince me of that.
The estimated r0 of 2/3 is hilarious. less contagious than sars eh? No amount of down-voting me or cdc papers is going to convince me of that.
FYI. The 5-6 number is also from the CDC 0_0
Subways seeded C19 in NYC:
https://web.mit.edu/jeffrey/harris/HarrisJE_WP2_COVID19_NYC_...
https://web.mit.edu/jeffrey/harris/HarrisJE_WP2_COVID19_NYC_...
I tried reading the paper and it seems like as much an argument that "people get coronavirus at work and take it home on the subway" as "people get coronavirus on the subway and take it home"...? What am I missing?
I would like to think that in a global pandemic costing hundreds of thousands of lives, trillions of dollars of economic costs, and significantly lowering the quality of life of future generations, this research would have been done months ago.
How hard can it be to find 100 similar workplaces, and to 33 of each say "You guys must wear masks". "You guys must have all windows open all the time". "You guys must wear gloves all the time".
Then wait 5 days, and see how infections spread.
That activity might lead to the deaths, in the worst case, of a couple of workers. Yet the knowledge gained would save tens of thousands.
How hard can it be to find 100 similar workplaces, and to 33 of each say "You guys must wear masks". "You guys must have all windows open all the time". "You guys must wear gloves all the time".
Then wait 5 days, and see how infections spread.
That activity might lead to the deaths, in the worst case, of a couple of workers. Yet the knowledge gained would save tens of thousands.
You don't even have to force people to behave one way or another.
You can skirt around the ethical issues by giving Sample A an unlimited supply of free masks, and keeping Sample B as the control sample. Even with free masks, not everyone in A will wear a mask. And some in B might still bring their own masks. But A will have higher mask use on average, and with large randomly selected populations you can tease out the impact using IV regression[1].
[1] https://en.wikipedia.org/wiki/Instrumental_variables_estimat...
You can skirt around the ethical issues by giving Sample A an unlimited supply of free masks, and keeping Sample B as the control sample. Even with free masks, not everyone in A will wear a mask. And some in B might still bring their own masks. But A will have higher mask use on average, and with large randomly selected populations you can tease out the impact using IV regression[1].
[1] https://en.wikipedia.org/wiki/Instrumental_variables_estimat...
We need, all of us, to stop focusing on deaths as the measure of how bad this can be. You're asking people to not only place their lives on the line, but even if that doesn't happen they face a significant risk of weeks of ICU care, followed potentially by a lifetime of respiratory problems.
And medical bills!
With 30 seconds of thought you are failing to control for:
* Social habits of the company
* Number of infected people within the company
* Compliance with the protocol
* Age demographics
* Infection rates from places other than the company
* Weird selection bias resulting from the company needing to not lock down to begin with
Very, very difficult study
* Social habits of the company
* Number of infected people within the company
* Compliance with the protocol
* Age demographics
* Infection rates from places other than the company
* Weird selection bias resulting from the company needing to not lock down to begin with
Very, very difficult study
As long as the participants are randomly selected, all of those factors drop out into noise. The law of large numbers guarantees you that as sample sizes go to infinity, the magnitude in difference between the i.i.d. variables in the samples goes to zero.
* We don't have infinity, or sufficiently large numbers of companies to do this
* We don't have the resources to test sufficiently large numbers of companies like this
* The dependent variable in question is going to be entirely dependent on the number of people infected at a company at the beginning of the study, which is unknowable unless you can test everyone... which we can't.
* We don't have the resources to test sufficiently large numbers of companies like this
* The dependent variable in question is going to be entirely dependent on the number of people infected at a company at the beginning of the study, which is unknowable unless you can test everyone... which we can't.
We can accomplish many great things if we knowingly discard ethics for the sake of efficiency, yes.
I question if modern ethics are perhaps too focussed of the wellbeing of the individual, at the expense of the wellbeing of all of us...
Or, to put it more bluntly, a modern ethics committee would have rejected the idea of installing sewers in cities to prevent disease because one builder of the sewer might have died in the process. Without that, industrialisation probably would never have happened, and we'd all be subsistence farmers today.
Or, to put it more bluntly, a modern ethics committee would have rejected the idea of installing sewers in cities to prevent disease because one builder of the sewer might have died in the process. Without that, industrialisation probably would never have happened, and we'd all be subsistence farmers today.
This is especially true with studies.
Because it was thought unethical to conduct studies around masks and infectious disease, the evidence was sparse, so the WHO and CDC didn't recommend wearing them. This has directly led to tens of thousands of deaths.
Because it was thought unethical to conduct studies around masks and infectious disease, the evidence was sparse, so the WHO and CDC didn't recommend wearing them. This has directly led to tens of thousands of deaths.
Very relevant to another article on HN today, "Why we can't build":
"The institutions through which Americans build have become biased against action rather than toward it. They’ve become, in political scientist Francis Fukuyama’s term, “vetocracies,” in which too many actors have veto rights over what gets built. That’s true in the federal government. It’s true in state and local governments. It’s even true in the private sector."
"The institutions through which Americans build have become biased against action rather than toward it. They’ve become, in political scientist Francis Fukuyama’s term, “vetocracies,” in which too many actors have veto rights over what gets built. That’s true in the federal government. It’s true in state and local governments. It’s even true in the private sector."
> Or, to put it more bluntly, a modern ethics committee would have rejected the idea of installing sewers
You get to choose whether to be in the business of installing sewers. Saying that it's ok to force people into medical experiments against their will for the greater good is how you get Nazi holocaust atrocities. Medical ethics has a long history that it sounds like you might enjoy spending some time reading about.
You get to choose whether to be in the business of installing sewers. Saying that it's ok to force people into medical experiments against their will for the greater good is how you get Nazi holocaust atrocities. Medical ethics has a long history that it sounds like you might enjoy spending some time reading about.
OP should start with Mengele for some truly chilling experiments at the bottom of the slippery slope.
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We're all being forced into a medical experiment against our will. Might as well be a useful one.
> We're all being forced into a medical experiment against our will.
I'm disappointed by your false equivalence between being told to stay home and safe and being made into a guinea pig.
If being home and safe means you lose necessary income, then your ire should be directed at your governments at all levels for refusing to prepare critical safety nets and regulatory environments that would make it possible for you to stay alive and safe without laboring every day. But advocating a regression on everything that history has taught us about medical ethics is terrible and bad. We're talking about thousands of years of accumulated and refined history lessons here. Medical ethics is a perfect example of why learning history is important.
I'm disappointed by your false equivalence between being told to stay home and safe and being made into a guinea pig.
If being home and safe means you lose necessary income, then your ire should be directed at your governments at all levels for refusing to prepare critical safety nets and regulatory environments that would make it possible for you to stay alive and safe without laboring every day. But advocating a regression on everything that history has taught us about medical ethics is terrible and bad. We're talking about thousands of years of accumulated and refined history lessons here. Medical ethics is a perfect example of why learning history is important.
> I'm disappointed by your false equivalence between being told to stay home and safe and being made into a guinea pig.
This is the false equivalence. How long does one have to stay home in order to be "safe"? If things calm down now, will they be worse in the winter? Will we still have to be "safe"? How do the consequences of curve flattening strategies that look more like half-hearted eradication attempts be compared to approaches that look literally like curve flattening?
Noone knows these answers.
This is the false equivalence. How long does one have to stay home in order to be "safe"? If things calm down now, will they be worse in the winter? Will we still have to be "safe"? How do the consequences of curve flattening strategies that look more like half-hearted eradication attempts be compared to approaches that look literally like curve flattening?
Noone knows these answers.
Yes, the natural experiment is being right now. You have the Western European countries with a social safety net that allows people to stay home for a few months to ride out the plague and the US, where such a thing does not exist.
This has economic repercussions. A good amount of meat processing plants are now idled because the workforce is off sick due to lack of protective equipment and sick leave. We are looking at meat shortages. I hope people make the right connections.
This has economic repercussions. A good amount of meat processing plants are now idled because the workforce is off sick due to lack of protective equipment and sick leave. We are looking at meat shortages. I hope people make the right connections.
Might-have-beens have no relevance to the ethics of the choices we make now. We are in the middle of a vast medico-economic experiment. It is bizarre to consider the ethics of only the medical side of the experiment, not the experiment as a whole.
What "medico-economic" experiment?! This is much an experiment as "living in a war-torn country" or "being hit by a major natural disaster" is an experiment.
If people start to starve because we stopped being able to produce food or people start dying of other causes because our basic infrastructure start collapsing, then you can start talking about ethical dilemmas.
If people start to starve because we stopped being able to produce food or people start dying of other causes because our basic infrastructure start collapsing, then you can start talking about ethical dilemmas.
> If people start to starve because we stopped being able to produce food or people start dying of other causes because our basic infrastructure start collapsing, then you can start talking about ethical dilemmas.
I think its a safe bet that this is already happening on small scales. Noone is measuring the degree.
I think its a safe bet that this is already happening on small scales. Noone is measuring the degree.
Food insecurity already happens in many places around the world, even rich countries. However, in those places it is an social-economical issue, not a lack of labor/resources to produce the food needed for the population.
There may be images of long lines of unemployed people that have to get from the government or food banks, but the food is still there. Farmers are still producing, distribution networks are still working, essential services operating. That part of the economy is still going.
There may be images of long lines of unemployed people that have to get from the government or food banks, but the food is still there. Farmers are still producing, distribution networks are still working, essential services operating. That part of the economy is still going.
Not really in this case though. Ethically there's not much of a concern with that study since we don't know what works so we're not doing any harm by prescribing known bad methods. The ethical harm would come from a poor study design that won't tell us anything useful. Getting good data from a study like this is really difficult, and we can't really accomplish anything by discarding good data for the sake of efficiency
It's not hard to tell people to do that. It is hard to get people to really comply and avoid changing behavior just by enrolling them in a study. It's hard to select 100 workplaces that are similar enough that they can be compared to eachother and also representative of the myriad complex types of social areas that people congregate in - opening a window might work in one type of office but not at all in another situation. And also, you need a control. You can tell a group of people to not change their behavior in a global pandemic to see what the impact of each intervention was. But getting people to comply? You even have problems in clinical trials where groups of patients find ways to get together and discuss side effects they've been having to try and figure out who has the placebo and who has the real drug killing the trial. Running statistically rigorous trials on that scale to get good information is just really difficult because of the study subjects.
<Insert GIF of Shrek's King speech: Some of you may die in the process, but that is a sacrifice I am willing to make>
This experiment has kind of been done: some countries had everyone wear masks. Other countries said "whoever told you to wear a mask is dangerously wrong, and even if you have a mask you can't wear it for fear of public shaming because we've told everyone that you're cheating healthcare staff out of their protection by doing so".
And then look at the infection spread in each country.
And then look at the infection spread in each country.
I think part of the problem is that this doesn't fit neatly into any existing specialty. The "microscopic scale of nucleic acids or on the gargantuan scale of whole nations" both have very active research programs targeted at them, particularly the former. It's "the everyday face-to-face scale of inches and feet" that fails to have a scientific home.
Let me know when you're volunteering to be a rat in this experiment.
All of us have already volunteered to be a rat in a global experiment of sorts anyway. I'm not sure why volunteering for three plausible paths would be bad. With this kind of study, self selection might even be ok.
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i take this as a positive sign that the national conversation might be starting to finally move beyond fear and panic to reason and understanding.
the primary mechanism of transmission (droplets into the nasopharangeal area) has been known since at least february (when it started to become regular news here in the US) and probably since at least december in china when it became a known infectious agent.
the better we understand the situations and environments where transmission is materially increased, the faster we devise reasonable mitigations and get back to some semblance of normalcy.
it's also important to debunk false mitigations that only serve to mollify the skittish (e.g., elaborate germophobic rituals) and thereby obstruct understanding and cause other harms. in fact, some of those mitigations can increase transmission risk simply by providing a false sense of relief (e.g., constant, but inevitably incorrect, mask usage).
the primary mechanism of transmission (droplets into the nasopharangeal area) has been known since at least february (when it started to become regular news here in the US) and probably since at least december in china when it became a known infectious agent.
the better we understand the situations and environments where transmission is materially increased, the faster we devise reasonable mitigations and get back to some semblance of normalcy.
it's also important to debunk false mitigations that only serve to mollify the skittish (e.g., elaborate germophobic rituals) and thereby obstruct understanding and cause other harms. in fact, some of those mitigations can increase transmission risk simply by providing a false sense of relief (e.g., constant, but inevitably incorrect, mask usage).
> the primary mechanism of transmission [...] has been known
I thought the entire point of this post was that there were multiple competing theories and little agreement or certainty? Your use of the phrase "has been known" implies a broad consensus in public health circles. I've seen very little consensus on any feature of this pandemic.
I thought the entire point of this post was that there were multiple competing theories and little agreement or certainty? Your use of the phrase "has been known" implies a broad consensus in public health circles. I've seen very little consensus on any feature of this pandemic.
no, the point of the article was that while there are competing theories of transmission, the centrality of the ballistic transmission mechanism has been known for a while (from prior coronavirus studies) and has been relatively undisputed as the primary transmission vector. to wit (from the article),
> "When do COVID-19 SSEs happen? Based on the list I’ve assembled, the short answer is: Wherever and whenever people are up in each other’s faces, laughing, shouting, cheering, sobbing, singing, greeting, and praying. You don’t have to be a 19th-century German bacteriologist or MIT expert in mucosalivary ballistics to understand what this tells us about the most likely mode of transmission."
> "When do COVID-19 SSEs happen? Based on the list I’ve assembled, the short answer is: Wherever and whenever people are up in each other’s faces, laughing, shouting, cheering, sobbing, singing, greeting, and praying. You don’t have to be a 19th-century German bacteriologist or MIT expert in mucosalivary ballistics to understand what this tells us about the most likely mode of transmission."
The fog of war seems to be relenting, but as a casual observer it's been maddening to see so much conflicting information and the corresponding cherry-picking of information to assert that this is overblown.
Is it possible to test various mechanisms of infection on monkeys? Sprays at various concentrations in their noses, in their mouths, on objects in their environment. Seems feasible and useful, but maybe there are concerns about how the results would generalize.
For extra credit, spray in their mouth through a basic cloth mask.
For extra credit, spray in their mouth through a basic cloth mask.
There are _humans_ who are currently volunteering to get infected by the virus who would probably gladly participate in such tests.
https://www.nature.com/articles/d41586-020-01179-x
And I'm one of them, but I'm not optimistic that human challenge trials will actually end up getting approved. Medical ethics is a deeply, deeply inflexible field even in the face of doom.
It would be illegal to do this with monkeys but ferrets have the same ACE2 protein we do and would be good candidates for this sort of research.
Hmm...I swear I've read a paper talking about monkeys infected, having mild symptoms and then recovering. Perhaps it was a SARS-1 paper.
It could also be from outside the US?
They do infect monkeys:
https://www.thesun.co.uk/news/11026173/lab-monkeys-infected-...
Are any monkeys even susceptible to it?
I remember reading some study about monkeys reliably developing antibodies to it.
When thinking about whether 2m social distancing is enough when coughs and sneezes can travel viable infected virus much further, my understanding is that governments care about onward transition rates. If on average an infected person infects less than one other person it will eventually fade out.
So the question is does the 2m separation push the averages towards that? I would think it does. Partly because the number of people within a blast radius of a cough or sneeze is much lower, and secondly the probability of infection drops with distance.
Social pressure that then drives coughing and sneezing people home in a social distancing environment probably reinforces the effect of reducing transmission rates.
Is it enough? That will have to be measured and analysed probably much later.
So the question is does the 2m separation push the averages towards that? I would think it does. Partly because the number of people within a blast radius of a cough or sneeze is much lower, and secondly the probability of infection drops with distance.
Social pressure that then drives coughing and sneezing people home in a social distancing environment probably reinforces the effect of reducing transmission rates.
Is it enough? That will have to be measured and analysed probably much later.
"It is theoretically possible that socioeconomically privileged individuals really do lack some immune-response mechanism that protects individuals who have been exposed to a wider array of infectious pathogens. (A recent report on COVID-19 surveillance testing at a Boston homeless shelter contained the stunning disclosure that 36 percent of 408 screened individuals tested positive for COVID-19. Yet the vast majority were asymptomatic, and even the few who were symptomatic did not diverge statistically from the 64 percent of tested individuals who were COVID-19-negative.)"
Interesting. Having spent some time in SF, can attest that the homeless - on occasion - appear to have super human immune systems.
Interesting. Having spent some time in SF, can attest that the homeless - on occasion - appear to have super human immune systems.
I wonder if it's the case that the filtering out of any risk factors has already been done on the homeless population. Homeless people with marginal health unfortunately don't live long. Those that have survived a long life as homeless are very likely to be the most robust humans alive.
Survivor bias. You're not seeing the dead ones.
Yeah, but did they control for people with “Germanic foreheads”?
https://threader.app/thread/1252581933835575297
This is a super interesting point of view.
This is a super interesting point of view.
I read through most of that but will admit that I don't quite understand what he was trying to get at. Can you summarize?
it more or less says that people who get met a lot (...directed graph, remember) somewhat counter-intuitively increase the total percentage of people infected more than you'd expect even if they don't transmit the disease after they contract it more than an 'average' person (again, directed graph).
I guess that doesn't seem counter-intuitive to me.
That's the whole reason behind social distancing right? To reduce the likelihood that you will contract the virus from someone else. It's not so much about keeping from getting other people sick, it's about keeping yourself from getting sick.
As someone with young kids and a more frequent exposure to norovirus and other stomach bugs than I'd like to admit, once that gets into the family, everyone gets it. The way to avoid it is to not go places where your kid is going to pick it up (public library usually), but in general you still go to those places because they are convenient for other reasons.
I understand the focus on handwashing and sanitizing things, but that doesn't do anything for direct exposure. If the stomach bug is near you, you're getting it. I assume coronavirus is going to be much the same.
That's the whole reason behind social distancing right? To reduce the likelihood that you will contract the virus from someone else. It's not so much about keeping from getting other people sick, it's about keeping yourself from getting sick.
As someone with young kids and a more frequent exposure to norovirus and other stomach bugs than I'd like to admit, once that gets into the family, everyone gets it. The way to avoid it is to not go places where your kid is going to pick it up (public library usually), but in general you still go to those places because they are convenient for other reasons.
I understand the focus on handwashing and sanitizing things, but that doesn't do anything for direct exposure. If the stomach bug is near you, you're getting it. I assume coronavirus is going to be much the same.
I only read the beginning, but it seemed to be about transmission not being completely transitive.
I think this thread does a terrible job of explaining its point. I've no idea if it's accurate, but the premise seems to be that people who are highly likely to get the virus do more to spread it than people who are likely to connect with many people conditioned on getting the virus in the first place, with acknowledgements that the two labels are likely to co-exist.
Just throwing it out there, I think this is likely going to be true, and the populations with higher proportions of old people are going to see greater infection rates than populations with fewer old people. That is to say, those who are vulnerable to the disease have a greater likelihood of getting other people sick than people who are naturally resistant to the disease but will behave irresponsibly. If you had a city with nobody over age 50, not only would the death rates be trivial due to the health of the population, but the spread of the virus would be very small.
I also don't think the views here hold once a non trivial proportion of the population is infected, like we have now, so it probably doesn't matter and is hard to act on anyway.
Just throwing it out there, I think this is likely going to be true, and the populations with higher proportions of old people are going to see greater infection rates than populations with fewer old people. That is to say, those who are vulnerable to the disease have a greater likelihood of getting other people sick than people who are naturally resistant to the disease but will behave irresponsibly. If you had a city with nobody over age 50, not only would the death rates be trivial due to the health of the population, but the spread of the virus would be very small.
I also don't think the views here hold once a non trivial proportion of the population is infected, like we have now, so it probably doesn't matter and is hard to act on anyway.
it is interesting but it's also kind of common sense: of course people who contact a lot, whether they initiate the contact or not, are at risk. the thread gives some interesting results about models but epidemiologists, from what i hear, don't talk about superspreaders as in people but superspreader events which result in a lot of infected in a short time span. i don't think simple models like SIR capture these things at all.
This is a pretty good piece.
The work done in the restaurant paper is really good. It was a clever natural experiment but clearly was a lot of work to piece together.
The work done in the restaurant paper is really good. It was a clever natural experiment but clearly was a lot of work to piece together.
For all my cynicism with politics, I was really impressed that the mayor of Austin stepped up and forced the cancelation of SXSW. That’s an enormous amount of money for the community, and it could not have been easy. Not a lot of “lessons in courage” these days, but I really think that was one.
(This subthread was originally in reply to https://news.ycombinator.com/item?id=22956128)
"The community" receiving this money in each of these cases refers to a very small percentage of the overall population of the region.
I would bet that the majority of small businesses in Austin bank on the yearly spike in traffic, and that missing out on that is a very big deal.
Austin has more than 10x more people every day than attend SWSX which lasts for less than 2 weeks. It’s even less significant as many people avoid the area during big events. Perhaps a 5% increase in sales for under 3% of the year so what 0.15% increase as a high estimate over the year.
The people attending an event like SXSW aren't like your regular citizens. The wealth profile is different. The visitors have spending money, often a lot of it. Many will treat the event as vacation or otherwise a justification for indulging themselves. Some will be able to expense their spending. Taking this into account, as well as geographical concentration, I can easily imagine that restaurants and cafes in the area could have 100% increase in sales for the duration of the event.
The quoted numbers are extremely likely inflated but feel free to use: $355.9 million impact on Austin’s economy / 146Billion in the metropolitan statical area = 0.24% as an overly generous guess. Aka including staff who then spend that income on other things. That’s still less than the shutdown costs over a few days.
In the end the overwhelming majority of people are not throwing down thousands of dollars per day at bars and restaurants.
In the end the overwhelming majority of people are not throwing down thousands of dollars per day at bars and restaurants.
That $356M is probably much more concentrated than the $146 billion.
As the old parable goes, maybe it doesn't make a difference to all those thousands of starfishes washed on the shore, but it made a difference to those few the boy threw back into the sea.
As the old parable goes, maybe it doesn't make a difference to all those thousands of starfishes washed on the shore, but it made a difference to those few the boy threw back into the sea.
Most of that 356M is not really concentrated consisting of money cycling through the economy.
A small percentage is going to be quite concentrated, but at that point you’re not really talking about Austin. Just the people actually running the event.
In terms of impact on local small business it’s still a small revenue bump as SWSX pushes tourists to chose other dates or other cities with cheaper hotel rooms etc. Further, most companies don’t have the slack to really benefit from such events. Something like a 2-3 percent boost in a local bar’s annual profit seems possible, just not that important relative to a shutdown.
A small percentage is going to be quite concentrated, but at that point you’re not really talking about Austin. Just the people actually running the event.
In terms of impact on local small business it’s still a small revenue bump as SWSX pushes tourists to chose other dates or other cities with cheaper hotel rooms etc. Further, most companies don’t have the slack to really benefit from such events. Something like a 2-3 percent boost in a local bar’s annual profit seems possible, just not that important relative to a shutdown.
According to this[1], SXSW brings Austin about $350 million annually. According to Wikipedia, Austin's annual GDP is about $1.5B so 350/1500 = roughly 23% of the city's annual GDP.
Anecdotally I know of many people who work year round to prepare for an event at SXSW and rely on it for their entire annual income.
Cancelling SXSW is a big deal to this city. It hurts. It's not to be downplayed.
[1] https://austin.culturemap.com/news/city-life/09-27-17-econom...
Anecdotally I know of many people who work year round to prepare for an event at SXSW and rely on it for their entire annual income.
Cancelling SXSW is a big deal to this city. It hurts. It's not to be downplayed.
[1] https://austin.culturemap.com/news/city-life/09-27-17-econom...
You're off by a factor of 100. Austin's GDP is ~$150 billion.
That GDP number is way off. 1.5B / 1 million people is 1,500$ per person. https://en.wikipedia.org/wiki/List_of_U.S._metropolitan_area... Gives 146B in 2018.
That’s 350M number is also extremely suspect, at a minimum including existing city residents as the hotel reservations are vastly below attendance.
Still even assuming that 350M was correct and not ridiculously inflated it’s 350/146,000 = 0.2%.
That’s 350M number is also extremely suspect, at a minimum including existing city residents as the hotel reservations are vastly below attendance.
Still even assuming that 350M was correct and not ridiculously inflated it’s 350/146,000 = 0.2%.
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You're confusing GDP with GDP per capita, and also 350,000,000 / 1,460,000,000 = 0.23972602739 and to convert that to a percentage you multiply by 100 so you get 23.973% as the result.
The number from wikipedia was 146 Billion (26 Austin-Round Rock, TX 146,784 metropolitan statistical area in millions of dollars) if you looked at the link I gave. Which is 146,784,000,000, though you could argue the city is a smaller area. Remember, thousand 3 zeros, Million 6 zeros, Billion 9 zeroes.
The GDP per capita was simply a sanity check showing how 1.4B must be wildly wrong.
https://en.wikipedia.org/wiki/List_of_U.S._metropolitan_area...
The GDP per capita was simply a sanity check showing how 1.4B must be wildly wrong.
https://en.wikipedia.org/wiki/List_of_U.S._metropolitan_area...
"SXSW brings Austin about $350 million annually."
Is that $350 million into the city taxes, or just $350 million for some private citizens, apparently some of whom you know and for whom it is undoubtedly a big deal.
Is that $350 million into the city taxes, or just $350 million for some private citizens, apparently some of whom you know and for whom it is undoubtedly a big deal.
It's $350 million in economic activity brought to or generated in the city, not in tax revenue. You can see the breakdown here.
https://explore.sxsw.com/hubfs/2019%20SXSW%20Economic%20Impa...
https://explore.sxsw.com/hubfs/2019%20SXSW%20Economic%20Impa...
Not necessarily.
There's a big halo effect on these sorts of things. When hotel rooms get booked, housekeepers get more hours, bartenders get more tips, restaurants get more covers, etc.
For the event itself you also have the carpenters who assemble the stages, security staff, garbage runs, etc.
There's a big halo effect on these sorts of things. When hotel rooms get booked, housekeepers get more hours, bartenders get more tips, restaurants get more covers, etc.
For the event itself you also have the carpenters who assemble the stages, security staff, garbage runs, etc.
Also taxis and rideshares get a spike in orders, more coffee and food is taken to go, more people visit bars and pubs for afterparties, more souvenirs are bought, ... Big events cause a lot of ancillary spending to happen.
This is extremely incorrect. A significant part of Austin’s economy is built on SXSW. Many small businesses here developed in tandem and cannot survive without it. Then there is the second- and third-order effects, such as those on contractors and freelancers.
Spend any significant amount of time in a tourist city and you'll find this isn't necessarily true. People plan their entire lives and balance sheets around these events.
> If small-droplet airborne concentrations in unventilated spaces were a common vector for COVID-19 transmission (as with measles, for instance), one would expect whole office buildings to become mass-infection hot spots.
There is some logical fallacy here. Large droplets don't exclude aerosol transmission, so you can attribute to it everything you attribute to large droplets too. There are also such superspreading events of whole building getting infected past lockdown, like the whole family dorm building getting infected where people share bathrooms and such.
There is some logical fallacy here. Large droplets don't exclude aerosol transmission, so you can attribute to it everything you attribute to large droplets too. There are also such superspreading events of whole building getting infected past lockdown, like the whole family dorm building getting infected where people share bathrooms and such.
> It’s similarly notable that airplanes don’t seem to be common sites for known SSEs, notwithstanding the sardine-like manner in which airlines transport us and the ample opportunity that the industry’s bureaucracy offers for contact tracing. Yes, New Zealand has one cluster that’s based around an infected but asymptomatic flight attendant. But the many known infections he caused took place at a wedding reception, not in an airplane. This flight attendant was running what was, in effect, an unintended experiment, with the passengers on board his aircraft playing the role of control group. And the results offer a microcosm of the nature of SSEs as a whole.
This is something straight out of a TV crime show:
> As the authors note, the restaurant in question was air-conditioned on the date in question. Using video footage, they were able to chart the position of every diner in the restaurant, and then map their subsequent infection status in relation to both the single infected individual known to be present at the time and the air conditioning system’s outgoing and intake streams. If the primary transmission mode of COVID-19 were by small, sub-Flüggian airborne particles, the presence of the forced air convection might have made the environment safer (especially since “smear samples from the air conditioner [itself] were all [COVID-19] nucleotide negative”). But the researchers instead found evidence for the opposite: “The key factor for infection was the direction of the airflow,” with downstream individuals being most at risk—a result consistent with the thesis that COVID-19 is transmitted primarily through the ballistic transmission of large respiratory droplets.
I could easily imagine that having been a key insight in an episode of "Bones" or "Elementary".
(If you are looking for something good to binge watch during COVID "stay at home", I recommend "Elementary", currently on Hulu and CBS All Access. It's a Sherlock Holmes set in modern times series. They did a really good job of taking many characters and plots from the original stories and adapting them in such a way that if you read the stories you will recognize them and perhaps even think you know what is going to happen--but they have changed just enough that the ending will still surprise you but also be eminently reasonable in hindsight. The stories that aren't obviously based on any particular original are equally good).