9 ms·

How are people catching COVID-19? It would be good to hear plausible scenarios of how people still catch it despite of masks and social distancing. There is so

How are people catching COVID-19? It would be good to hear plausible scenarios of how people still catch it despite of masks and social distancing. There is something to learn from each story. And I see a distinct lack of focus on anecdotal stories of how people think they caught it. How the fuck are people catching this disease?

Marsymars 6y ago
I expect mostly poor hygiene when it comes to touching contaminated things and faces. I basically can't go out in public without seeing someone with their mask pulled down to talk/eat/smoke. You should be sanitizing your hands every single time you don or doff a mask.
- rootusrootus 6y ago
  There have been studies of influenza that suggest nearly 100% of all transmission occurs through coughing & sneezing and inhaling the output. To a close approximation, handwashing does exactly zero to stop it from spreading. Scientists seem to think the same is likely true for SC2. Which isn't to say you shouldn't wash your hands, because there are other things you get on your hand which can make you ill. It means keep the damn mask on, and don't take it off until you're well out of range of other people.
  - taeric 6y ago
    This has been nagging me. Feels like we are dangerously close to many taking "precautions" as a signaling move more than being cautious. :(
  - Johnjonjoan 6y ago
    If you're going to say hand washing doesn't affect transmission rates please at the very least post sources. If that turns out to be misinformation it could be extremely dangerous advice.
- Mediterraneo10 6y ago
  > I basically can't go out in public without seeing someone with their mask pulled down to talk/eat/smoke. Many countries that have lifted their lockdowns and are now requiring masks in the post-lockdown stage, require those masks to be worn only on public transportation or in shops. Overall, public-health authorities do not believe that people pulling down their mask in the open air to eat or talk on their phone, will significantly change the infection curve for the worst. Let us remember that the public-health goal here is not to prohibit any and all behavior that could potentially, under very ideal circumstances, result in transmission. Rather, the goal is to institute a few general rules that will flatten the curve to the point where contact tracing is effective. People should heed their local authorities on what to do, but I am troubled by the moral panic where posters such the above are insisting on even more stringent behavior than required by the public-health authorities. With regard to hand-washing, touching things is now seen as so relatively unlikely a form of transmission, that some countries which initially required supermarkets to provide gloves and hand sanitizer, have decided to lift that requirement (while keeping the mask requirement). Of course hand washing in general is a good thing, but authorities in many countries do not think that obsessively doing so will make a real impact on COVID-19 transmission rates across society.
  - DanBC 6y ago
    > Overall, public-health authorities do not believe that people pulling down their mask in the open air to eat or talk on their phone, will significantly change the infection curve for the worst. No. "Public health authorities" are all really clear: if you're going to wear PPE you need to do it properly. DIY cloth masks are not PPE, they're theatre, so it doesn't really matter whether you wear it or not. > With regard to hand-washing, touching things is now seen as so relatively unlikely a form of transmission This is untrue. Some people on HN are fixated on droplets and aerosols, but we know that fomites are a significant risk. https://www.nejm.org/doi/full/10.1056/NEJMra032498 https://www.nejm.org/doi/full/10.1056/NEJMra032498 > The primary mode of transmission appears to be through direct or indirect contact of mucous membrane (eyes, nose, or mouth) with infectious respiratory droplets or fomites.3,26,27 The use of aerosol-generating procedures (such as endotracheal intubation, bronchoscopy, and treatment with aerosolized medication) in hospitals may amplify the transmission of SARS-CoV, and outbreaks have involved more than 100 patients on occasion.3,26-28 SARS-CoV survives for many days when dried on surfaces and in feces at an alkaline pH.33 Although data from direct comparisons are not yet available, a review of previously published data suggests that SARS-CoV may be far more stable than other human respiratory viruses, such as respiratory syncytial virus. The role of fecal–oral transmission is unknown but may be important, given that profuse watery diarrhea is a common feature of the disease and that SARS-CoV is shed in large quantities in stool.
jeremiahhs 6y ago
I've read very few reports of actual infection scenarios. This is one https://wwwnc.cdc.gov/eid/article/26/7/20-0764_article https://wwwnc.cdc.gov/eid/article/26/7/20-0764_article Image https://i.insider.com/5ea01ef938bf2357b9756173?width=750&format=jpeg&auto=webp https://i.insider.com/5ea01ef938bf2357b9756173?width=750&for... As we are two months into this, we really should be getting regular updates on infection events.
mdturnerphys 6y ago
This article summarizes some different case studies and scenarios: https://www.erinbromage.com/post/the-risks-know-them-avoid-them https://www.erinbromage.com/post/the-risks-know-them-avoid-t...
- taeric 6y ago
  That page keeps crashing in my phone. :( I got to toilette hypothesis, so don't know if the rest had data. That said, this still sounded like speculation. Are the rest more backed with data?
  - marcosdumay 6y ago
    TL.DR. from that page: It's airbone. The less air, more people and longer exposition in an environment, the higher the risk. Surfaces play a significant but minor role, outside exposure (a lot of air) is almost irrelevant as long as people don't stay long close to each other.
  - deleted 6y ago
    [deleted]
AuryGlenz 6y ago
Most people out there have “essential” jobs and can’t work from home. How could they not still catch it? All it takes is one eye rub, forgetting to sanitize your hands before you eat, etc.
pwg 6y ago
> It would be good to hear plausible scenarios of how people still catch it despite of masks and social distancing. One of the issues is that not everyone is wearing masks or properly social distancing. If you have any opportunity to go out and safely observe from a distance any groups, you'll notice a sizable fraction not wearing masks and many not properly distancing themselves. All it takes is some percentage of those who are not mask wearing or distancing also being asymptomatic spreaders to keep the spread going.
- taeric 6y ago
  This still doesn't answer the question. If wearing a mask keeps you from spreading it, the question is how did you get it? With the reasoning you are giving, a single case of this will have to spread to lethal numbers quickly. But the more we learn, the more it seems it was here for a while before it broke into long term care facilities and deaths started spiking.
  - Touche 6y ago
    I don't know what you find so hard to believe. Many people are not wearing masks. Many people are not distancing. Those people, and their family members, are getting it. People who work with one of these people and then touch their face get it, etc.
    - taeric 6y ago
      This is flat against your first point. You are now relying on folks not being in a mask having more of a chance of getting it. Not of spreading it. So, again, what is the actual vector here. How are folks getting it? I confess I believe the general idea. But it has been pushed with a ton of heavy handed bs from folks saying how much they protect you. And then completely neglect to account for the scores of folks in masks that are still getting it. How?
      - chadcmulligan 6y ago
        It's the same as any virus - how do you catch a cold? Its the virus gets in somehow, you touch it on a surface, then touch your face, scratch yourself. This one seems to need a lot of touches which is why you need to be in close proximity to others who have it for a while.
klyrs 6y ago
At my local grocery store, they carefully arrange hard cheeses like Parmesan so that the price tag is hidden from view. If you comparison shop, that means you'll be touching several packets before making your final selection. And when you bring it home, it's coming along with the fingerprints of perhaps a half-dozen other customers. If it's shrink-wrapped plastic, you can wash it (do you?) -- if it's wrapped in clingfilm, you can't wash it without harming the cheese, so you need to somehow remove it from its packaging without carrying over the contamination. That's just a piece of cheese. One of the difficulties in disease modeling is how very many transmission vectors that aren't accounted for.
kerakaali 6y ago
You're assuming people are following protocol. Humans undergo lapses in judgement multiple times a day and are just as forgetful. Just the other day, I found myself having scratched my face under the mask while at the supermarket, something I only realised after the fact. Many people don't realise how much contact spread can occur in just half an hour as well, as seen [0]. This was modelling the spread inside of a dining hall of a cruise ship, but you can imagine similar behaviour in other public spaces. [0] https://youtu.be/9cZTfUAYrF8 https://youtu.be/9cZTfUAYrF8
- therockspush 6y ago
  It reminds me of a buddy telling me about his MOPP training in the Air Force. He said if there was ever a large scale biological/chemical attack, trying to decontaminate and drink water through a tube in your gas mask was going to get overwhelming real quick. It just takes one bad drink. The gas mask strapped to your leg was just a security blanket. https://www.airforcemag.com/goldfein-time-to-dust-off-the-mopp-gear-because-covid-19-isnt-going-away/ https://www.airforcemag.com/goldfein-time-to-dust-off-the-mo...
rcxdude 6y ago
a) masks and social distancing only reduce the risk of transmission substantially, they do not eliminate it. Especially in the case of essential workers and stuff like grocery shopping b) not everyone is socially distancing to the same degree.
javagram 6y ago
1. Many people don’t have masks. Cloth masks aren’t as effective as N95s anyway and we don’t have nearly enough N95s. New York serology survey shows FEWER health care workers have caught the virus than general population - because only health care workers have access to and training in how to use N95s, face shields, gowns and goggles. 2. Many people are still working in industries where they aren’t social distancing, e.g. all the meat packing plant outbreaks where sick employees were ordered to continue working in close proximity to their coworkers and nearly every employee in the plant got infected. 3. Positive cases are being sent home to quarantine in the same residence as their uninfected family members, who then catch the virus. Some other countries are either quarantining sick cases in the hospital, in hotels, or in monitored quarantine sites, but we haven’t been doing that in most cases and so we send home a positive case and they then infect everyone else in their home. This is worst in nursing homes but is happening in multigenerational households and other households as well. https://www.nydailynews.com/coronavirus/ny-coronavirus-cuomo-coronavirus-stats-20200506-eyqui4b5lfdn7g6cqswkf6otly-story.html https://www.nydailynews.com/coronavirus/ny-coronavirus-cuomo...
graeme 6y ago
People are still going to grocery stores, pharmacies. Lots of people break quarantine and visit others. In some areas stores and places of worship are still open. And we don’t isolate people outside the home, so people spread to family/roommates. Further, the virus can take 5-14 days to show symptoms, and people don’t go for a test immediately. So confirmed cases lag actual infections.
kens 6y ago
I find the Korean call center paper pretty interesting [1]. In early March, this building had 97 infections: 89 on one half of one floor, 5 on the other half of the floor, and 3 on other floors. The two halves of the floor were separated by doors but shared the elevators, bathrooms, etc. It seems clear from this that almost all of the infections were from being in a shared space with someone infected. (There's a nice diagram of the infections [2].) The other thing I got from the article is that South Korea is on a whole different level of testing than the US. When infection was detected, they tested everyone who was in the building or had visited: 1143 people tested with results in 12-24 hours. Everyone positive was isolated and everyone negative was quarantined and re-tested for 14 days. They also texted 16,628 people who had been near the building for more than 5 minutes (from cell data), telling them to avoid contact with others and get tested. This level of testing and tracing got South Korea (51 million people) to the point that it is now averaging just 10 new cases per day. [1] https://wwwnc.cdc.gov/eid/article/26/8/20-1274_article https://wwwnc.cdc.gov/eid/article/26/8/20-1274_article [2] https://wwwnc.cdc.gov/eid/article/26/8/20-1274-f2 https://wwwnc.cdc.gov/eid/article/26/8/20-1274-f2
- leereeves 6y ago
  > South Korea is on a whole different level of testing than the US According to [1] and [2], the US has performed twice as many tests per capita as South Korea. Roughly: The US has performed 8.9 million tests for a population of 330 million (27 tests per thousand people). South Korea has performed 660 thousand tests for a population of 50 million (13 tests per thousand people). 1: https://www.realclearpolitics.com/coronavirus/ https://www.realclearpolitics.com/coronavirus/ 2: https://ourworldindata.org/coronavirus-testing#how-many-total-tests-have-been-performed https://ourworldindata.org/coronavirus-testing#how-many-tota...
  - krn 6y ago
    > According to [1] and [2], the US has performed twice as many tests per capita as South Korea. That's probably because South Korea managed to quickly contain the spread by starting large-scale testing much much earlier. And its number of new daily cases of COVID-19 reached the peak on February 29.
guscost 6y ago
I think that you are considerably underestimating how small and numerous viruses are, and how difficult one like this is to stop once it's spreading in a community. They've evolved for billions of years to do exactly this, and they are very good at it.

Marsymars 6y ago

I expect mostly poor hygiene when it comes to touching contaminated things and faces. I basically can't go out in public without seeing someone with their mask pulled down to talk/eat/smoke. You should be sanitizing your hands every single time you don or doff a mask.

rootusrootus 6y ago
There have been studies of influenza that suggest nearly 100% of all transmission occurs through coughing & sneezing and inhaling the output. To a close approximation, handwashing does exactly zero to stop it from spreading. Scientists seem to think the same is likely true for SC2. Which isn't to say you shouldn't wash your hands, because there are other things you get on your hand which can make you ill. It means keep the damn mask on, and don't take it off until you're well out of range of other people.
- taeric 6y ago
  This has been nagging me. Feels like we are dangerously close to many taking "precautions" as a signaling move more than being cautious. :(
- Johnjonjoan 6y ago
  If you're going to say hand washing doesn't affect transmission rates please at the very least post sources. If that turns out to be misinformation it could be extremely dangerous advice.
Mediterraneo10 6y ago
> I basically can't go out in public without seeing someone with their mask pulled down to talk/eat/smoke. Many countries that have lifted their lockdowns and are now requiring masks in the post-lockdown stage, require those masks to be worn only on public transportation or in shops. Overall, public-health authorities do not believe that people pulling down their mask in the open air to eat or talk on their phone, will significantly change the infection curve for the worst. Let us remember that the public-health goal here is not to prohibit any and all behavior that could potentially, under very ideal circumstances, result in transmission. Rather, the goal is to institute a few general rules that will flatten the curve to the point where contact tracing is effective. People should heed their local authorities on what to do, but I am troubled by the moral panic where posters such the above are insisting on even more stringent behavior than required by the public-health authorities. With regard to hand-washing, touching things is now seen as so relatively unlikely a form of transmission, that some countries which initially required supermarkets to provide gloves and hand sanitizer, have decided to lift that requirement (while keeping the mask requirement). Of course hand washing in general is a good thing, but authorities in many countries do not think that obsessively doing so will make a real impact on COVID-19 transmission rates across society.
- DanBC 6y ago
  > Overall, public-health authorities do not believe that people pulling down their mask in the open air to eat or talk on their phone, will significantly change the infection curve for the worst. No. "Public health authorities" are all really clear: if you're going to wear PPE you need to do it properly. DIY cloth masks are not PPE, they're theatre, so it doesn't really matter whether you wear it or not. > With regard to hand-washing, touching things is now seen as so relatively unlikely a form of transmission This is untrue. Some people on HN are fixated on droplets and aerosols, but we know that fomites are a significant risk. https://www.nejm.org/doi/full/10.1056/NEJMra032498 https://www.nejm.org/doi/full/10.1056/NEJMra032498 > The primary mode of transmission appears to be through direct or indirect contact of mucous membrane (eyes, nose, or mouth) with infectious respiratory droplets or fomites.3,26,27 The use of aerosol-generating procedures (such as endotracheal intubation, bronchoscopy, and treatment with aerosolized medication) in hospitals may amplify the transmission of SARS-CoV, and outbreaks have involved more than 100 patients on occasion.3,26-28 SARS-CoV survives for many days when dried on surfaces and in feces at an alkaline pH.33 Although data from direct comparisons are not yet available, a review of previously published data suggests that SARS-CoV may be far more stable than other human respiratory viruses, such as respiratory syncytial virus. The role of fecal–oral transmission is unknown but may be important, given that profuse watery diarrhea is a common feature of the disease and that SARS-CoV is shed in large quantities in stool.

jeremiahhs 6y ago

I've read very few reports of actual infection scenarios. This is one https://wwwnc.cdc.gov/eid/article/26/7/20-0764_article https://wwwnc.cdc.gov/eid/article/26/7/20-0764_article Image https://i.insider.com/5ea01ef938bf2357b9756173?width=750&format=jpeg&auto=webp https://i.insider.com/5ea01ef938bf2357b9756173?width=750&for... As we are two months into this, we really should be getting regular updates on infection events.

mdturnerphys 6y ago

This article summarizes some different case studies and scenarios: https://www.erinbromage.com/post/the-risks-know-them-avoid-them https://www.erinbromage.com/post/the-risks-know-them-avoid-t...

taeric 6y ago
That page keeps crashing in my phone. :( I got to toilette hypothesis, so don't know if the rest had data. That said, this still sounded like speculation. Are the rest more backed with data?
- marcosdumay 6y ago
  TL.DR. from that page: It's airbone. The less air, more people and longer exposition in an environment, the higher the risk. Surfaces play a significant but minor role, outside exposure (a lot of air) is almost irrelevant as long as people don't stay long close to each other.
- deleted 6y ago
  [deleted]

AuryGlenz 6y ago

Most people out there have “essential” jobs and can’t work from home. How could they not still catch it? All it takes is one eye rub, forgetting to sanitize your hands before you eat, etc.

pwg 6y ago

> It would be good to hear plausible scenarios of how people still catch it despite of masks and social distancing. One of the issues is that not everyone is wearing masks or properly social distancing. If you have any opportunity to go out and safely observe from a distance any groups, you'll notice a sizable fraction not wearing masks and many not properly distancing themselves. All it takes is some percentage of those who are not mask wearing or distancing also being asymptomatic spreaders to keep the spread going.

taeric 6y ago
This still doesn't answer the question. If wearing a mask keeps you from spreading it, the question is how did you get it? With the reasoning you are giving, a single case of this will have to spread to lethal numbers quickly. But the more we learn, the more it seems it was here for a while before it broke into long term care facilities and deaths started spiking.
- Touche 6y ago
  I don't know what you find so hard to believe. Many people are not wearing masks. Many people are not distancing. Those people, and their family members, are getting it. People who work with one of these people and then touch their face get it, etc.
  - taeric 6y ago
    This is flat against your first point. You are now relying on folks not being in a mask having more of a chance of getting it. Not of spreading it. So, again, what is the actual vector here. How are folks getting it? I confess I believe the general idea. But it has been pushed with a ton of heavy handed bs from folks saying how much they protect you. And then completely neglect to account for the scores of folks in masks that are still getting it. How?
    - chadcmulligan 6y ago
      It's the same as any virus - how do you catch a cold? Its the virus gets in somehow, you touch it on a surface, then touch your face, scratch yourself. This one seems to need a lot of touches which is why you need to be in close proximity to others who have it for a while.

klyrs 6y ago

At my local grocery store, they carefully arrange hard cheeses like Parmesan so that the price tag is hidden from view. If you comparison shop, that means you'll be touching several packets before making your final selection. And when you bring it home, it's coming along with the fingerprints of perhaps a half-dozen other customers. If it's shrink-wrapped plastic, you can wash it (do you?) -- if it's wrapped in clingfilm, you can't wash it without harming the cheese, so you need to somehow remove it from its packaging without carrying over the contamination. That's just a piece of cheese. One of the difficulties in disease modeling is how very many transmission vectors that aren't accounted for.

kerakaali 6y ago

You're assuming people are following protocol. Humans undergo lapses in judgement multiple times a day and are just as forgetful. Just the other day, I found myself having scratched my face under the mask while at the supermarket, something I only realised after the fact. Many people don't realise how much contact spread can occur in just half an hour as well, as seen [0]. This was modelling the spread inside of a dining hall of a cruise ship, but you can imagine similar behaviour in other public spaces. [0] https://youtu.be/9cZTfUAYrF8 https://youtu.be/9cZTfUAYrF8

therockspush 6y ago
It reminds me of a buddy telling me about his MOPP training in the Air Force. He said if there was ever a large scale biological/chemical attack, trying to decontaminate and drink water through a tube in your gas mask was going to get overwhelming real quick. It just takes one bad drink. The gas mask strapped to your leg was just a security blanket. https://www.airforcemag.com/goldfein-time-to-dust-off-the-mopp-gear-because-covid-19-isnt-going-away/ https://www.airforcemag.com/goldfein-time-to-dust-off-the-mo...

rcxdude 6y ago

a) masks and social distancing only reduce the risk of transmission substantially, they do not eliminate it. Especially in the case of essential workers and stuff like grocery shopping b) not everyone is socially distancing to the same degree.

javagram 6y ago

1. Many people don’t have masks. Cloth masks aren’t as effective as N95s anyway and we don’t have nearly enough N95s. New York serology survey shows FEWER health care workers have caught the virus than general population - because only health care workers have access to and training in how to use N95s, face shields, gowns and goggles. 2. Many people are still working in industries where they aren’t social distancing, e.g. all the meat packing plant outbreaks where sick employees were ordered to continue working in close proximity to their coworkers and nearly every employee in the plant got infected. 3. Positive cases are being sent home to quarantine in the same residence as their uninfected family members, who then catch the virus. Some other countries are either quarantining sick cases in the hospital, in hotels, or in monitored quarantine sites, but we haven’t been doing that in most cases and so we send home a positive case and they then infect everyone else in their home. This is worst in nursing homes but is happening in multigenerational households and other households as well. https://www.nydailynews.com/coronavirus/ny-coronavirus-cuomo-coronavirus-stats-20200506-eyqui4b5lfdn7g6cqswkf6otly-story.html https://www.nydailynews.com/coronavirus/ny-coronavirus-cuomo...

graeme 6y ago

People are still going to grocery stores, pharmacies. Lots of people break quarantine and visit others. In some areas stores and places of worship are still open. And we don’t isolate people outside the home, so people spread to family/roommates. Further, the virus can take 5-14 days to show symptoms, and people don’t go for a test immediately. So confirmed cases lag actual infections.

kens 6y ago

I find the Korean call center paper pretty interesting [1]. In early March, this building had 97 infections: 89 on one half of one floor, 5 on the other half of the floor, and 3 on other floors. The two halves of the floor were separated by doors but shared the elevators, bathrooms, etc. It seems clear from this that almost all of the infections were from being in a shared space with someone infected. (There's a nice diagram of the infections [2].) The other thing I got from the article is that South Korea is on a whole different level of testing than the US. When infection was detected, they tested everyone who was in the building or had visited: 1143 people tested with results in 12-24 hours. Everyone positive was isolated and everyone negative was quarantined and re-tested for 14 days. They also texted 16,628 people who had been near the building for more than 5 minutes (from cell data), telling them to avoid contact with others and get tested. This level of testing and tracing got South Korea (51 million people) to the point that it is now averaging just 10 new cases per day. [1] https://wwwnc.cdc.gov/eid/article/26/8/20-1274_article https://wwwnc.cdc.gov/eid/article/26/8/20-1274_article [2] https://wwwnc.cdc.gov/eid/article/26/8/20-1274-f2 https://wwwnc.cdc.gov/eid/article/26/8/20-1274-f2

leereeves 6y ago
> South Korea is on a whole different level of testing than the US According to [1] and [2], the US has performed twice as many tests per capita as South Korea. Roughly: The US has performed 8.9 million tests for a population of 330 million (27 tests per thousand people). South Korea has performed 660 thousand tests for a population of 50 million (13 tests per thousand people). 1: https://www.realclearpolitics.com/coronavirus/ https://www.realclearpolitics.com/coronavirus/ 2: https://ourworldindata.org/coronavirus-testing#how-many-total-tests-have-been-performed https://ourworldindata.org/coronavirus-testing#how-many-tota...
- krn 6y ago
  > According to [1] and [2], the US has performed twice as many tests per capita as South Korea. That's probably because South Korea managed to quickly contain the spread by starting large-scale testing much much earlier. And its number of new daily cases of COVID-19 reached the peak on February 29.

guscost 6y ago

I think that you are considerably underestimating how small and numerous viruses are, and how difficult one like this is to stop once it's spreading in a community. They've evolved for billions of years to do exactly this, and they are very good at it.