9 ms·

I have a theory: From reading a bunch of case studies, it seems that the main route of transmission is microdroplets hanging in the air. A huge majority of tr

I have a theory: From reading a bunch of case studies, it seems that the main route of transmission is microdroplets hanging in the air. A huge majority of transmission comes from being near someone for an extended period of time (30 min or so) indoors. Since smoking is allowed in most casinos, they have extremely powerful ventilation and air filtration systems, so that their non-smoking customers aren't excessively bothered. If you've been in a Vegas casino and seen someone smoking, you notice that the smoke almost instantly gets sucked into the ceiling. This may dramatically reduce transmission in casinos or other venues that allow smoking.

dwd 7y ago
The initial 15 min rule (for whether you might get infected from close proximity to someone infected) was based on the idea that offices cycle their volume of air every 10 minutes, but casinos that allowing smoking may cycle their air more often. This was often cited as a reason why everyone on a flight won't catch it, just those in nearby rows. Vegas also doesn't have a subway system, which was cited as why it spread so rapidly in NY.
- astrange 7y ago
  Many places that are doing well (esp in Asia) have more extensive subway systems than NYC. However the people there might be more hygienic, or maybe the operators are cleaning more often.
  - rosywoozlechan 7y ago
    Or wear masks.
  - rwallace 7y ago
    I've seen it plausibly argued that in e.g. Japan, they have a culture of not talking on your phone on the subway, and this substantially reduces transmission.
    - nl 7y ago
      This is true - not only do they have a culture of that, they have signs up telling people not to talk on their phones and to be quiet.
      - keithnoizu 7y ago
        And angry elders who will glare at you violently if you don't adhere to the rule.
    - iso947 7y ago
      London just the same https://www.theguardian.com/uk-news/2016/sep/29/tube-chat-campaign-provokes-horror-among-london-commuters https://www.theguardian.com/uk-news/2016/sep/29/tube-chat-ca...
  - fiblye 7y ago
    I think one thing is NY is testing like crazy. They're actually trying to find out just how many people are infected. Some countries are still trying to avoid testing. Many Japanese hospitals are turning people away from testing unless they have severe symptoms lasting several days, so naturally, numbers look tiny. And let's be frank, China's numbers just shouldn't be believed.
    - iso947 7y ago
      You can’t hide excess deaths, at least in the developed world. Japan has not had 20,000 deaths.
      - thu2111 7y ago
        Japan's population is lower than the USA. You're comparing absolute numbers when what you want is per million. The US doesn't have high quality national excess death data, apparently. That's surprising. Part of the distorted response to this outbreak is because most countries only seem to publish relatively recent excess death data - often only a few years. But when longer term data is examined it shows that there have been plenty of flu seasons with similar death rates. That's why people keep comparing it to the flu. At a national level the peak in the USA was at 20,000 excess deaths. In 2017 the peak was at about 7,000 (https://talkingpointsmemo.com/news/cdc-releases-detailed-national-excess-death-data https://talkingpointsmemo.com/news/cdc-releases-detailed-nat...) So it must be much worse, right? Well, not really. If you look at the longer term data for a hard-hit country like the UK, where there are a lot of lockdown-created excess deaths due to excessively underloading the hospitals: http://inproportion2.talkigy.com/ http://inproportion2.talkigy.com/ You can see that this outbreak had at the end of April an almost identical number of excess deaths so far this year to 2017, 1999 (which was worse), 1998, 1996 and 1995. It seems flu care might have got better over time, or perhaps vaccinations had the impact. But so far the impact on COVID on the UK is not much different to disease outbreaks throughout the 1990s. The UK stats will go up and it'll be worse than any other outbreak for sure, because at this point the population is in a state of fear and avoiding hospitals - even if they don't want to, critical treatments for other diseases have been cancelled to free up space for a surge that never came. https://www.telegraph.co.uk/news/2020/04/27/care-homes-see-rise-deaths-not-linked-coronavirus-hospitals/ https://www.telegraph.co.uk/news/2020/04/27/care-homes-see-r... "UK's biggest provider says deaths among residents at three times last year's rate, but only half of additional deaths linked to virus" And this is with almost any death being ascribed to COVID, without requiring tests or evidence. The lockdown will claim more lives than COVID will.
  - freepor 7y ago
    You cannot compare situations in the US to situations in Asia since the populations are so different. In Asian countries people wear masks regularly... in the US the Vice President considered it too emasculating even for a HOSPITAL visit. There are plenty of good things about Americans but some of their worst qualities are a perfect match for disease transmission.
  - usrusr 7y ago
    The NYC subway seems to have a pretty unique local microclimate though. I don't know if it's just the lack of regenerative braking or if the close proximity to the iconic steam heating network is also playing a role in this, but compared to most other subway networks, the MTA feels like a living history museum - even if you close your eyes, block your ears and only take in the air. The influence of air heat and moisture on virus spread is quite complicated (evaporation ends some droplet classes, condensation ends others) so it's quite possible that some subway systems are much worse spreaders than others.
  - dwd 7y ago
    The vast majority wear masks and the operators wear gloves - and this is when there's not an active epidemic. You get the impression that a lot of people in Western society would rather risk infection than be seen wearing a mask - defies logic.
- jcranmer 7y ago
  > Vegas also doesn't have a subway system, which was cited as why it spread so rapidly in NY. There's no real evidence to support the thesis that the MTA was a primary vector of spread in NYC. Granular data of infection rate by neighborhood is spotty, but the data that does exist doesn't show any clear trends towards increased infection rates nearer subway lines. And the borough with the highest infection rate is the borough with the least transit ridership, and the borough with the lowest infection rate is that with the highest transit ridership... (Source cite: https://pedestrianobservations.com/2020/04/15/the-subway-is-probably-not-why-new-york-is-a-disaster-zone/ https://pedestrianobservations.com/2020/04/15/the-subway-is-...).
  - cameldrv 7y ago
    I think it’s pretty clear that having a large portion of the city spend an hour a day packed together with 80 or so other people is going to increase transmission from a droplet spread disease.
    - jgwil2 7y ago
      Interesting hypothesis. We should sill look at the evidence before stating it as fact.
      - cameldrv 7y ago
        In Wuhan, 11% of traced contacts came back to transport. One thing that might help would be to open the windows in the subway cars.
    - jcranmer 7y ago
      As opposed to people living packed together in dense apartment blocks? Or working in crowded office blocks? Or spending leisure time in crowded recreational facilities? Or shopping in crowded stories? Or eating in crowded restaurants? Yes, subways are crowded, but so is everything else in NYC. As for why NYC is doing much worse than other comparably dense cities worldwide, my thesis is that it's a failure at all levels of civic participation (federal, state, local, and even residential and commercial proprietors) to be proactive in counteracting the spread of coronavirus.
- noobermin 7y ago
  On the one hand you say it won't spread in airplanes but will spread on a train, literally contradicting the sense between those two sentences.
  - andbberger 7y ago
    Not a contradiction as it is not a direct comparison. Planes have substantially greater ventilation then trains on average.
    - bitexploder 7y ago
      They also have HEPA filters, etc.
- raverbashing 7y ago
  Or maybe because Vegas isn't Vegas (I mean this - https://www.reviewjournal.com/uncategorized/knowing-vegas-why-isnt-the-strip-in-las-vegas/ https://www.reviewjournal.com/uncategorized/knowing-vegas-wh... ) and most of the participants came from abroad or other cities in the US. So if people got contaminated there, in a couple of days they probably were somewhere else already.
  - gonzo 7y ago
    Born n raised in Vegas. It’s a technical distinction that most locals don’t understand or care about.
    - raverbashing 7y ago
      I agree, but do Vegas COVID statistics mean cases only in Vegas or the adjacent cities? As a similar example, a lot of people in NJ work in NY but a case on a NJ resident would be counted as NJ.
  - lurquer 7y ago
    So, what happens in Vegas doesn't stay in Vegas.
dkdk8283 7y ago
Casino airflow doesn’t explain the low rate for residents who don’t visit or work at Casinos.
- joe_the_user 7y ago
  Well, the primary reason you'd expect a higher than average rate in Nevada is Casinos. Without that, Vegas would have an average rate - plus, is Casinos are the main social outlet, those who don't go to Casinos might not go anywhere and be less likely to get the virus.
  - dkdk8283 7y ago
    Locals avoid Casinos unless they work there. I lived there only for a year but avoiding tourists was primary #1.
    - greglindahl 7y ago
      My Vegas-resident brother-in-law loved counting cards and betting on unpopular baseball teams, both of which involved entering casinos. Perhaps data is better than our two anecdotes?
      - dkdk8283 7y ago
        Fair point, you’re right.
      - nl 7y ago
        Google mobility reports[1] show workplaces down 55% and retail and recreation down 47% for Clark County, Nevada (where Las Vegas is), and both dropped very quickly from March 13. [1] https://www.google.com/covid19/mobility/ https://www.google.com/covid19/mobility/ (Look for Nevada under the US)
  - nradov 7y ago
    Las Vegas residents go to stores, restaurants, gyms, etc just like everyone else. Other than the casinos it's an average urban areas.
nicodjimenez 7y ago
Nice theory!
jbay808 7y ago
Huh. Strong forced air evacuation is also common in restaurants, bars, and cafes in Japan, where until very recently smoking indoors was commonplace.
joe_the_user 7y ago
It's remarkable to me that there hasn't been an effort construct strong anti-covid ventilation/filtration systems, made even with air "disinfectant". Then again, they can't even give health care workers PPEs.
- nexuist 7y ago
  I mean, HVAC systems are supposed to remain usable for 20+ years, it's not really something you can throw on a production line in a matter of days. Most likely, someone already is working on such a system.
  - AtlasLion 7y ago
    They already exist, i saw a video on hvac systems used in a moroccan pop-up hospital, air coming in or leaving the building goes through filtration and then through a désinfection machine. They didn't explain the method used though.
    - adrianN 7y ago
      I'd guess a strong UV-C light would kill the virus pretty reliably.
    - nl 7y ago
      Normal HEPA filters can stop the virus: https://thewirecutter.com/blog/can-hepa-air-purifiers-capture-coronavirus/ https://thewirecutter.com/blog/can-hepa-air-purifiers-captur...
- greglindahl 7y ago
  Hospitals have had such systems for decades: Negative pressure rooms make sure that the bad air goes out through an exhaust that you can clean or at least keep well away from people. Some cars have HEPA filters, and airplanes often have more sophisticated systems than that.
- cameldrv 7y ago
  There should be. There are a few options. UV-C in the air handlers seems like the easiest retrofit but I’m not sure how effective it is.
dba7dba 7y ago
I heard a crazy theory from some foreign tourists visiting Vegas many years ago. The story I heard is that Vegas hotels/casinos mix in small amount of certain gas/chemical in the circulating air that makes people not want to sleep, which makes people gamble more and spend more money. Some crazy theories people have... So I can see (as a non-expert) that the well ventilated casinos is the reason for low infection rate in Vegas. NYC on the other hand has had the extremely highly infection rate because EVERYONE has to take subway and pretty sure there's not much air circulation in the subway cars... Either way, I think not spending too much time indoors is the key to avoid covid-19. Unfortunately most all indoor space has recirculated, air-conditioned, stale air. Edit: I personally think businesses that can leave windows open for fresh air will have lower chance of spreading Covid-19 than ones with barely functioning AC system with little air circulation.
amrx431 7y ago
Look at Indian subcontinent, the entire Indian subcontinent has over 20% of world's population and yet couple of thousand deaths due to Covid. I believe micro-droplets being evaporated by the notorious South Asian heat is playing a part.
- gpderetta 7y ago
  They are apparently under an extremely strict lock down though. Still I suspect the extreme differences between countries and even regions between countries will be studied for many years to come.
  - econcon 7y ago
    Google achohol lines in India. Tell me it's strict lockdown, it used to be, now it isn't anymore.
- selimthegrim 7y ago
  Call me back after Ramadan is over in PK.

dwd 7y ago

The initial 15 min rule (for whether you might get infected from close proximity to someone infected) was based on the idea that offices cycle their volume of air every 10 minutes, but casinos that allowing smoking may cycle their air more often. This was often cited as a reason why everyone on a flight won't catch it, just those in nearby rows. Vegas also doesn't have a subway system, which was cited as why it spread so rapidly in NY.

astrange 7y ago
Many places that are doing well (esp in Asia) have more extensive subway systems than NYC. However the people there might be more hygienic, or maybe the operators are cleaning more often.
- rosywoozlechan 7y ago
  Or wear masks.
- rwallace 7y ago
  I've seen it plausibly argued that in e.g. Japan, they have a culture of not talking on your phone on the subway, and this substantially reduces transmission.
  - nl 7y ago
    This is true - not only do they have a culture of that, they have signs up telling people not to talk on their phones and to be quiet.
    - keithnoizu 7y ago
      And angry elders who will glare at you violently if you don't adhere to the rule.
  - iso947 7y ago
    London just the same https://www.theguardian.com/uk-news/2016/sep/29/tube-chat-campaign-provokes-horror-among-london-commuters https://www.theguardian.com/uk-news/2016/sep/29/tube-chat-ca...
- fiblye 7y ago
  I think one thing is NY is testing like crazy. They're actually trying to find out just how many people are infected. Some countries are still trying to avoid testing. Many Japanese hospitals are turning people away from testing unless they have severe symptoms lasting several days, so naturally, numbers look tiny. And let's be frank, China's numbers just shouldn't be believed.
  - iso947 7y ago
    You can’t hide excess deaths, at least in the developed world. Japan has not had 20,000 deaths.
    - thu2111 7y ago
      Japan's population is lower than the USA. You're comparing absolute numbers when what you want is per million. The US doesn't have high quality national excess death data, apparently. That's surprising. Part of the distorted response to this outbreak is because most countries only seem to publish relatively recent excess death data - often only a few years. But when longer term data is examined it shows that there have been plenty of flu seasons with similar death rates. That's why people keep comparing it to the flu. At a national level the peak in the USA was at 20,000 excess deaths. In 2017 the peak was at about 7,000 (https://talkingpointsmemo.com/news/cdc-releases-detailed-national-excess-death-data https://talkingpointsmemo.com/news/cdc-releases-detailed-nat...) So it must be much worse, right? Well, not really. If you look at the longer term data for a hard-hit country like the UK, where there are a lot of lockdown-created excess deaths due to excessively underloading the hospitals: http://inproportion2.talkigy.com/ http://inproportion2.talkigy.com/ You can see that this outbreak had at the end of April an almost identical number of excess deaths so far this year to 2017, 1999 (which was worse), 1998, 1996 and 1995. It seems flu care might have got better over time, or perhaps vaccinations had the impact. But so far the impact on COVID on the UK is not much different to disease outbreaks throughout the 1990s. The UK stats will go up and it'll be worse than any other outbreak for sure, because at this point the population is in a state of fear and avoiding hospitals - even if they don't want to, critical treatments for other diseases have been cancelled to free up space for a surge that never came. https://www.telegraph.co.uk/news/2020/04/27/care-homes-see-rise-deaths-not-linked-coronavirus-hospitals/ https://www.telegraph.co.uk/news/2020/04/27/care-homes-see-r... "UK's biggest provider says deaths among residents at three times last year's rate, but only half of additional deaths linked to virus" And this is with almost any death being ascribed to COVID, without requiring tests or evidence. The lockdown will claim more lives than COVID will.
- freepor 7y ago
  You cannot compare situations in the US to situations in Asia since the populations are so different. In Asian countries people wear masks regularly... in the US the Vice President considered it too emasculating even for a HOSPITAL visit. There are plenty of good things about Americans but some of their worst qualities are a perfect match for disease transmission.
- usrusr 7y ago
  The NYC subway seems to have a pretty unique local microclimate though. I don't know if it's just the lack of regenerative braking or if the close proximity to the iconic steam heating network is also playing a role in this, but compared to most other subway networks, the MTA feels like a living history museum - even if you close your eyes, block your ears and only take in the air. The influence of air heat and moisture on virus spread is quite complicated (evaporation ends some droplet classes, condensation ends others) so it's quite possible that some subway systems are much worse spreaders than others.
- dwd 7y ago
  The vast majority wear masks and the operators wear gloves - and this is when there's not an active epidemic. You get the impression that a lot of people in Western society would rather risk infection than be seen wearing a mask - defies logic.
jcranmer 7y ago
> Vegas also doesn't have a subway system, which was cited as why it spread so rapidly in NY. There's no real evidence to support the thesis that the MTA was a primary vector of spread in NYC. Granular data of infection rate by neighborhood is spotty, but the data that does exist doesn't show any clear trends towards increased infection rates nearer subway lines. And the borough with the highest infection rate is the borough with the least transit ridership, and the borough with the lowest infection rate is that with the highest transit ridership... (Source cite: https://pedestrianobservations.com/2020/04/15/the-subway-is-probably-not-why-new-york-is-a-disaster-zone/ https://pedestrianobservations.com/2020/04/15/the-subway-is-...).
- cameldrv 7y ago
  I think it’s pretty clear that having a large portion of the city spend an hour a day packed together with 80 or so other people is going to increase transmission from a droplet spread disease.
  - jgwil2 7y ago
    Interesting hypothesis. We should sill look at the evidence before stating it as fact.
    - cameldrv 7y ago
      In Wuhan, 11% of traced contacts came back to transport. One thing that might help would be to open the windows in the subway cars.
  - jcranmer 7y ago
    As opposed to people living packed together in dense apartment blocks? Or working in crowded office blocks? Or spending leisure time in crowded recreational facilities? Or shopping in crowded stories? Or eating in crowded restaurants? Yes, subways are crowded, but so is everything else in NYC. As for why NYC is doing much worse than other comparably dense cities worldwide, my thesis is that it's a failure at all levels of civic participation (federal, state, local, and even residential and commercial proprietors) to be proactive in counteracting the spread of coronavirus.
noobermin 7y ago
On the one hand you say it won't spread in airplanes but will spread on a train, literally contradicting the sense between those two sentences.
- andbberger 7y ago
  Not a contradiction as it is not a direct comparison. Planes have substantially greater ventilation then trains on average.
  - bitexploder 7y ago
    They also have HEPA filters, etc.
raverbashing 7y ago
Or maybe because Vegas isn't Vegas (I mean this - https://www.reviewjournal.com/uncategorized/knowing-vegas-why-isnt-the-strip-in-las-vegas/ https://www.reviewjournal.com/uncategorized/knowing-vegas-wh... ) and most of the participants came from abroad or other cities in the US. So if people got contaminated there, in a couple of days they probably were somewhere else already.
- gonzo 7y ago
  Born n raised in Vegas. It’s a technical distinction that most locals don’t understand or care about.
  - raverbashing 7y ago
    I agree, but do Vegas COVID statistics mean cases only in Vegas or the adjacent cities? As a similar example, a lot of people in NJ work in NY but a case on a NJ resident would be counted as NJ.
- lurquer 7y ago
  So, what happens in Vegas doesn't stay in Vegas.

dkdk8283 7y ago

Casino airflow doesn’t explain the low rate for residents who don’t visit or work at Casinos.

joe_the_user 7y ago
Well, the primary reason you'd expect a higher than average rate in Nevada is Casinos. Without that, Vegas would have an average rate - plus, is Casinos are the main social outlet, those who don't go to Casinos might not go anywhere and be less likely to get the virus.
- dkdk8283 7y ago
  Locals avoid Casinos unless they work there. I lived there only for a year but avoiding tourists was primary #1.
  - greglindahl 7y ago
    My Vegas-resident brother-in-law loved counting cards and betting on unpopular baseball teams, both of which involved entering casinos. Perhaps data is better than our two anecdotes?
    - dkdk8283 7y ago
      Fair point, you’re right.
    - nl 7y ago
      Google mobility reports[1] show workplaces down 55% and retail and recreation down 47% for Clark County, Nevada (where Las Vegas is), and both dropped very quickly from March 13. [1] https://www.google.com/covid19/mobility/ https://www.google.com/covid19/mobility/ (Look for Nevada under the US)
- nradov 7y ago
  Las Vegas residents go to stores, restaurants, gyms, etc just like everyone else. Other than the casinos it's an average urban areas.

nicodjimenez 7y ago

Nice theory!

jbay808 7y ago

Huh. Strong forced air evacuation is also common in restaurants, bars, and cafes in Japan, where until very recently smoking indoors was commonplace.

joe_the_user 7y ago

It's remarkable to me that there hasn't been an effort construct strong anti-covid ventilation/filtration systems, made even with air "disinfectant". Then again, they can't even give health care workers PPEs.

nexuist 7y ago
I mean, HVAC systems are supposed to remain usable for 20+ years, it's not really something you can throw on a production line in a matter of days. Most likely, someone already is working on such a system.
- AtlasLion 7y ago
  They already exist, i saw a video on hvac systems used in a moroccan pop-up hospital, air coming in or leaving the building goes through filtration and then through a désinfection machine. They didn't explain the method used though.
  - adrianN 7y ago
    I'd guess a strong UV-C light would kill the virus pretty reliably.
  - nl 7y ago
    Normal HEPA filters can stop the virus: https://thewirecutter.com/blog/can-hepa-air-purifiers-capture-coronavirus/ https://thewirecutter.com/blog/can-hepa-air-purifiers-captur...
greglindahl 7y ago
Hospitals have had such systems for decades: Negative pressure rooms make sure that the bad air goes out through an exhaust that you can clean or at least keep well away from people. Some cars have HEPA filters, and airplanes often have more sophisticated systems than that.
cameldrv 7y ago
There should be. There are a few options. UV-C in the air handlers seems like the easiest retrofit but I’m not sure how effective it is.

dba7dba 7y ago

I heard a crazy theory from some foreign tourists visiting Vegas many years ago. The story I heard is that Vegas hotels/casinos mix in small amount of certain gas/chemical in the circulating air that makes people not want to sleep, which makes people gamble more and spend more money. Some crazy theories people have... So I can see (as a non-expert) that the well ventilated casinos is the reason for low infection rate in Vegas. NYC on the other hand has had the extremely highly infection rate because EVERYONE has to take subway and pretty sure there's not much air circulation in the subway cars... Either way, I think not spending too much time indoors is the key to avoid covid-19. Unfortunately most all indoor space has recirculated, air-conditioned, stale air. Edit: I personally think businesses that can leave windows open for fresh air will have lower chance of spreading Covid-19 than ones with barely functioning AC system with little air circulation.

amrx431 7y ago

Look at Indian subcontinent, the entire Indian subcontinent has over 20% of world's population and yet couple of thousand deaths due to Covid. I believe micro-droplets being evaporated by the notorious South Asian heat is playing a part.

gpderetta 7y ago
They are apparently under an extremely strict lock down though. Still I suspect the extreme differences between countries and even regions between countries will be studied for many years to come.
- econcon 7y ago
  Google achohol lines in India. Tell me it's strict lockdown, it used to be, now it isn't anymore.
selimthegrim 7y ago
Call me back after Ramadan is over in PK.