7 ms·

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 l

by gns24 6y ago

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.

zaroth 6y ago
What makes you think that crowded public transport didn’t pay a role in NY’s prevalence being so high?
- standardUser 6y ago
  Public transit certainly didn't cause NYC-like levels of transmission in Japan, though it has a similarly dense public transit system.
  - zaroth 6y ago
    Don’t riders almost universally wear masks on public transit in Japan?
    - drpgq 6y ago
      Not sure why you're getting downvoted. Mask wearing percentages on public transit is quite different in NYC compared to Tokyo.
    - jfoster 6y ago
      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.
    - esyir 6y ago
      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.
standardUser 6y ago
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).
- ceejayoz 6y ago
  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-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations 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.)
  - dboreham 6y ago
    >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 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 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.
    - ceejayoz 6y ago
      > 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.
raiyu 6y ago
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.
- ceejayoz 6y ago
  https://www.who.int/news-room/commentaries/detail/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations 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.
- Izkata 6y ago
  > 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-covid19-coronavirus-disease-may-be-twice-as-contagious-as-we-thought/#6bb67c2729a6 https://www.forbes.com/sites/tarahaelle/2020/04/07/the-covid...
  - s1artibartfast 6y ago
    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 https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article
tomohawk 6y ago
Subways seeded C19 in NYC: https://web.mit.edu/jeffrey/harris/HarrisJE_WP2_COVID19_NYC_13-Apr-2020.pdf https://web.mit.edu/jeffrey/harris/HarrisJE_WP2_COVID19_NYC_...
- jdm2212 6y ago
  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?

by gns24 6y ago

zaroth 6y ago

What makes you think that crowded public transport didn’t pay a role in NY’s prevalence being so high?

standardUser 6y ago
Public transit certainly didn't cause NYC-like levels of transmission in Japan, though it has a similarly dense public transit system.
- zaroth 6y ago
  Don’t riders almost universally wear masks on public transit in Japan?
  - drpgq 6y ago
    Not sure why you're getting downvoted. Mask wearing percentages on public transit is quite different in NYC compared to Tokyo.
  - jfoster 6y ago
    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.
  - esyir 6y ago
    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.

standardUser 6y ago

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).

ceejayoz 6y ago
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-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations 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.)
- dboreham 6y ago
  >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 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 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.
  - ceejayoz 6y ago
    > 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.

raiyu 6y ago

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.

ceejayoz 6y ago
https://www.who.int/news-room/commentaries/detail/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations 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.
Izkata 6y ago
> 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-covid19-coronavirus-disease-may-be-twice-as-contagious-as-we-thought/#6bb67c2729a6 https://www.forbes.com/sites/tarahaelle/2020/04/07/the-covid...
- s1artibartfast 6y ago
  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 https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article

tomohawk 6y ago

Subways seeded C19 in NYC: https://web.mit.edu/jeffrey/harris/HarrisJE_WP2_COVID19_NYC_13-Apr-2020.pdf https://web.mit.edu/jeffrey/harris/HarrisJE_WP2_COVID19_NYC_...

jdm2212 6y ago
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?