4 ms·

From the paper: "Our results indicate that aerosol and fomite transmission of HCoV-19 is plausible, as the virus can remain viable in aerosols for multiple hour

From the paper: "Our results indicate that aerosol and fomite transmission of HCoV-19 is plausible, as the virus can remain viable in aerosols for multiple hours and on surfaces up to days." This partially explains how quickly this virus spreads, and why such incredible measures are required to stop the spread.

nostromo 7y ago
> and why such incredible measures are required to stop the spread. Since we're learning that the fatality rate is much lower than SARS, as was feared early on, and that it's much more mild of an illness -- and also that it's highly contagious and already widespread -- it strikes me that the opposite is true. We should do everything we can to protect the elderly and ill, but a disease that is so mild that 85% of people over 80 still survive it, it doesn't strike me as something worth tanking the global economy over. If you're middle-aged or younger and you drive to work, travel internationally, drink alcohol, etc., you've taken similar risks as COVID-19 poses to you. This is incredibly unpopular on HN, and I'm ok with that. Holing everyone up in their apartments for the next year would put almost everyone reading this out of a job, many without housing, and without healthcare. This is a "keep calm, wash your hands, and carry on" moment, and we're failing.
- eloff 7y ago
  I think we have different definitions of mild. Something that kills 1% of healthy middle aged people is quite scary.
  - nostromo 7y ago
    It doesn't though. Here's a distribution of Italian deaths: https://external-preview.redd.it/nOYqCT3-3vzX6aPnaHk3Jb6LSvSnQIHxqYH6FPXrcfs.png?width=1024&auto=webp&s=c2e3ac21bbab29599bb3535c18057ab8d442f3e7 https://external-preview.redd.it/nOYqCT3-3vzX6aPnaHk3Jb6LSvS... Note that over half the deaths are over the average age of life expectancy of an Italian.
    - marcinzm 7y ago
      It doesn't when there's a functioning non overloaded health system. Italy's health system despite all the lockdown measures is barely functioning at this point (and can't stay in this state for long). Without efforts to slow transmission the death rate goes up a lot as anyone who'd need hospitalization is as good as dead. edit: And once your health system collapses anyone who needs hospitalization for any reason is in trouble.
- d4mi3n 7y ago
  I'd still be concerned about further mutation. With something as virulent as HCoV-19, even a minor increase in morbidity rates could be catastrophic. Even without high morbidity rates, a survival rate of 85% without treatment is still horrific in scenarios where local healthcare systems become overwhelmed. Reading accounts of just that happening in Italy is chilling.
- ardit33 7y ago
  There are reports, that plenty of those "80%" mild cases have pneumonia and permanent lung scaring (aka, you will never be able to play intense sports), even though they don't end up in a tube/forced oxygenation.... Sorry, I'd rather take a 2 months economy hit, than a long term burn.... which will cause a longer term economic problem as well.
  - nostromo 7y ago
    The decision isn't to either get it now or not at all. The decision if you'd like to get it now or later. If you decide to get it now, you probably have a job. If you decide to get it later, you quite possibly don't.
    - marcinzm 7y ago
      And if everyone gets it now the health system collapses, 15% of the infected die and anyone who needs a hospital for any life-saving reason also dies.
    - kyriakos 7y ago
      getting it later there's also a greater chance that an anti-viral treatment may become available.
  - ratfaced-guy 7y ago
    You’re gonna have to give a source for that, that sounds like complete doomer bullshit, I’ve been following this since early January and the only reports of permanent lung scarring are being mostly attributed to the need for mechanical intubation or absolute critical cases. Like anything else, it would be worse the older you are.
  - dogma1138 7y ago
    If you get pneumonia it can’t be a mild cases People really need to stop spreading misinformation.
- cjbprime 7y ago
  Your country (whichever one it is) doesn't have enough ICU beds for 10% of people over 70 -- it probably has orders of magnitude fewer available beds -- and note that people who don't die can still end up in hospital for weeks and requiring a respirator, increasing that percentage of beds required. My amateur understanding is that accelerated contagion of COVID-19 will destroy your country's health infrastructure, and then many people who don't have COVID-19 will start dying too because healthcare can't reach them. That's why delaying infection is so valuable. It's not just about the direct symptoms that most people get.
- astronautjones 7y ago
  > We should do everything we can to protect the elderly and ill, but a disease that is so mild that 85% of people over 80 still survive it, it doesn't strike me as something worth tanking the global economy over. If you're middle-aged or younger and you drive to work, travel internationally, drink alcohol, etc., you've taken similar risks as COVID-19 poses to you. You're wrong, though. Regardless of how dismissive you want to be about people getting the virus, they are going to have symptoms that make them seek treatment. the system cannot accommodate large numbers of people seeking treatment. No one is going to "keep calm" when they feel severely ill, they're going to rightly seek help from doctors. The crisis is when lots of people seek that help at once. We are trying to prevent that and it's worth it! If the US economy takes a shit, it's going to be because the government is offering no financial help whatsoever to the people who are going to be destitute when they miss work.
  - rimliu 7y ago
    Except there is no real treatment for the mild cases. "Stay home and wait till it is over".
slg 7y ago
I don't understand how this can be true and the R0 is somewhere in the 2-4 range as some are reporting. It seems like it would be incredibly easy to spread if someone can go days without knowing they have the virus and the virus can live for days on any surface they touch.
- RandallBrown 7y ago
  You typically need more than just 1 virus in your system to get infected. Your immune system will do a good job of taking care of the 1. The study just says they were able to detect live viruses after that amount of time, not that they would definitely infect you. It's likely that the odds of infection are very low before that 3 hour mark. Unless I'm misreading the study.
- etiam 7y ago
  If something has to give, it seems to me like a strong possibility it's the R0 range estimate. Authorities, and to some extent media, in my country have been very tenacious in trying to reassure people. Often up to the point of outright disinformation. At the start of this week the pacifier statement in vogue was that the mortality rate estimate is inflated because the severe cases are those who self-present for care. and thus testing. so if one counts all the cases, including the undetected ones, a much smaller fraction are lethal. Well, that one's true, but the flip side of that, which nobody here has wanted to address so far, is that to the extent the transmissibility is calculated based on corresponding data, that estimate is going to be deficient instead, because it's failing to include some of the contagion that resulted in cases that went undetected. Hopefully the people making the estimates know better than that because of other data sources, but the main one I can think of (maybe aside of South Korea's broad biochemical testing, which may be a relatively unbiased sample according to my perception?) is contact tracing of confirmed cases. And I think it's downright likely that at least our contact tracers would miss fomite transmission and persistent aerosol transmission until now, because the party line touted here, at least officially, is "you get the disease though close contact over a long time with someone who is sick" lately expanded to include "or if somebody coughs or sneezes at you" (emphasis mine). The other thing I can think of to somewhat reconcile the observations is even if the virus has a high durability in the environment, the total transmission process would be contingent on other factors too, one of which is the dose needed to get an infection going. I have a life science background, but not specific expertise in this area. Would appreciate if someone has good clarifications to share about how accurate the transmissibility estimates are likely to be and why.
akiselev 7y ago
The measles virus is much better studied and it behaves like the aerosol described. It's contagious to the point where any sort of contact in an enclosed space is practically guaranteed to infect anyone who isn't immunized from a vaccine or previous exposure (and sometimes even then). Based on the numbers South Korea has put out for numbers of infected vs tested and the extensive contact tracing they've done, it doesn't seem that this virus quite reaches that level of infectiousness. I think there's more to the story, like HCoV-19 may have a half life long enough for experiments to detect on surfaces and in an aerosol, but short enough that it doesn't present enough of a viral load to infect anyone relatively quickly.
altarius 7y ago
The only generally applicable information form the paper is the viral half-life in aerosols/on surfaces and comparing it to SARS-COV1. This won't help in determining how long to quarantine packages unless someone finds out what the typical viral transfer is e.g. when sneezing or when handling a package with contaminated hands - and how many/few viral particles "ingested" may cause an infection. I don't think one can simply conclude at all that "viruses will survive X days on cardboard/steel/plastic" because viral particles go through an exponential decay in the environment -- so more particles == more time to inactivate all the viruses, and the reverse. As far as I understand it, there's no predetermined "viable lifetime" (a sort of biologic clock and death) of a virus, the environment will just eventually destroy it and that point seems essentially random for an individual viral particle with different probability distributions on different surfaces. So if you start with a viral load that is higher, you will be able to detect viable viruses longer. So these numbers, e.g. detectable for 3 hours in aerosol don't mean anything unless the average human sneeze excretes as many viral particles as a "3-jet Collison nebulizer". If we excrete more than more viral particles remain viable longer and the detection threshold is reached later. If less, than those 3 hours don't apply.

nostromo 7y ago

> and why such incredible measures are required to stop the spread. Since we're learning that the fatality rate is much lower than SARS, as was feared early on, and that it's much more mild of an illness -- and also that it's highly contagious and already widespread -- it strikes me that the opposite is true. We should do everything we can to protect the elderly and ill, but a disease that is so mild that 85% of people over 80 still survive it, it doesn't strike me as something worth tanking the global economy over. If you're middle-aged or younger and you drive to work, travel internationally, drink alcohol, etc., you've taken similar risks as COVID-19 poses to you. This is incredibly unpopular on HN, and I'm ok with that. Holing everyone up in their apartments for the next year would put almost everyone reading this out of a job, many without housing, and without healthcare. This is a "keep calm, wash your hands, and carry on" moment, and we're failing.

eloff 7y ago
I think we have different definitions of mild. Something that kills 1% of healthy middle aged people is quite scary.
- nostromo 7y ago
  It doesn't though. Here's a distribution of Italian deaths: https://external-preview.redd.it/nOYqCT3-3vzX6aPnaHk3Jb6LSvSnQIHxqYH6FPXrcfs.png?width=1024&auto=webp&s=c2e3ac21bbab29599bb3535c18057ab8d442f3e7 https://external-preview.redd.it/nOYqCT3-3vzX6aPnaHk3Jb6LSvS... Note that over half the deaths are over the average age of life expectancy of an Italian.
  - marcinzm 7y ago
    It doesn't when there's a functioning non overloaded health system. Italy's health system despite all the lockdown measures is barely functioning at this point (and can't stay in this state for long). Without efforts to slow transmission the death rate goes up a lot as anyone who'd need hospitalization is as good as dead. edit: And once your health system collapses anyone who needs hospitalization for any reason is in trouble.
d4mi3n 7y ago
I'd still be concerned about further mutation. With something as virulent as HCoV-19, even a minor increase in morbidity rates could be catastrophic. Even without high morbidity rates, a survival rate of 85% without treatment is still horrific in scenarios where local healthcare systems become overwhelmed. Reading accounts of just that happening in Italy is chilling.
ardit33 7y ago
There are reports, that plenty of those "80%" mild cases have pneumonia and permanent lung scaring (aka, you will never be able to play intense sports), even though they don't end up in a tube/forced oxygenation.... Sorry, I'd rather take a 2 months economy hit, than a long term burn.... which will cause a longer term economic problem as well.
- nostromo 7y ago
  The decision isn't to either get it now or not at all. The decision if you'd like to get it now or later. If you decide to get it now, you probably have a job. If you decide to get it later, you quite possibly don't.
  - marcinzm 7y ago
    And if everyone gets it now the health system collapses, 15% of the infected die and anyone who needs a hospital for any life-saving reason also dies.
  - kyriakos 7y ago
    getting it later there's also a greater chance that an anti-viral treatment may become available.
- ratfaced-guy 7y ago
  You’re gonna have to give a source for that, that sounds like complete doomer bullshit, I’ve been following this since early January and the only reports of permanent lung scarring are being mostly attributed to the need for mechanical intubation or absolute critical cases. Like anything else, it would be worse the older you are.
- dogma1138 7y ago
  If you get pneumonia it can’t be a mild cases People really need to stop spreading misinformation.
cjbprime 7y ago
Your country (whichever one it is) doesn't have enough ICU beds for 10% of people over 70 -- it probably has orders of magnitude fewer available beds -- and note that people who don't die can still end up in hospital for weeks and requiring a respirator, increasing that percentage of beds required. My amateur understanding is that accelerated contagion of COVID-19 will destroy your country's health infrastructure, and then many people who don't have COVID-19 will start dying too because healthcare can't reach them. That's why delaying infection is so valuable. It's not just about the direct symptoms that most people get.
astronautjones 7y ago
> We should do everything we can to protect the elderly and ill, but a disease that is so mild that 85% of people over 80 still survive it, it doesn't strike me as something worth tanking the global economy over. If you're middle-aged or younger and you drive to work, travel internationally, drink alcohol, etc., you've taken similar risks as COVID-19 poses to you. You're wrong, though. Regardless of how dismissive you want to be about people getting the virus, they are going to have symptoms that make them seek treatment. the system cannot accommodate large numbers of people seeking treatment. No one is going to "keep calm" when they feel severely ill, they're going to rightly seek help from doctors. The crisis is when lots of people seek that help at once. We are trying to prevent that and it's worth it! If the US economy takes a shit, it's going to be because the government is offering no financial help whatsoever to the people who are going to be destitute when they miss work.
- rimliu 7y ago
  Except there is no real treatment for the mild cases. "Stay home and wait till it is over".

slg 7y ago

I don't understand how this can be true and the R0 is somewhere in the 2-4 range as some are reporting. It seems like it would be incredibly easy to spread if someone can go days without knowing they have the virus and the virus can live for days on any surface they touch.

RandallBrown 7y ago
You typically need more than just 1 virus in your system to get infected. Your immune system will do a good job of taking care of the 1. The study just says they were able to detect live viruses after that amount of time, not that they would definitely infect you. It's likely that the odds of infection are very low before that 3 hour mark. Unless I'm misreading the study.
etiam 7y ago
If something has to give, it seems to me like a strong possibility it's the R0 range estimate. Authorities, and to some extent media, in my country have been very tenacious in trying to reassure people. Often up to the point of outright disinformation. At the start of this week the pacifier statement in vogue was that the mortality rate estimate is inflated because the severe cases are those who self-present for care. and thus testing. so if one counts all the cases, including the undetected ones, a much smaller fraction are lethal. Well, that one's true, but the flip side of that, which nobody here has wanted to address so far, is that to the extent the transmissibility is calculated based on corresponding data, that estimate is going to be deficient instead, because it's failing to include some of the contagion that resulted in cases that went undetected. Hopefully the people making the estimates know better than that because of other data sources, but the main one I can think of (maybe aside of South Korea's broad biochemical testing, which may be a relatively unbiased sample according to my perception?) is contact tracing of confirmed cases. And I think it's downright likely that at least our contact tracers would miss fomite transmission and persistent aerosol transmission until now, because the party line touted here, at least officially, is "you get the disease though close contact over a long time with someone who is sick" lately expanded to include "or if somebody coughs or sneezes at you" (emphasis mine). The other thing I can think of to somewhat reconcile the observations is even if the virus has a high durability in the environment, the total transmission process would be contingent on other factors too, one of which is the dose needed to get an infection going. I have a life science background, but not specific expertise in this area. Would appreciate if someone has good clarifications to share about how accurate the transmissibility estimates are likely to be and why.

akiselev 7y ago

The measles virus is much better studied and it behaves like the aerosol described. It's contagious to the point where any sort of contact in an enclosed space is practically guaranteed to infect anyone who isn't immunized from a vaccine or previous exposure (and sometimes even then). Based on the numbers South Korea has put out for numbers of infected vs tested and the extensive contact tracing they've done, it doesn't seem that this virus quite reaches that level of infectiousness. I think there's more to the story, like HCoV-19 may have a half life long enough for experiments to detect on surfaces and in an aerosol, but short enough that it doesn't present enough of a viral load to infect anyone relatively quickly.

altarius 7y ago

The only generally applicable information form the paper is the viral half-life in aerosols/on surfaces and comparing it to SARS-COV1. This won't help in determining how long to quarantine packages unless someone finds out what the typical viral transfer is e.g. when sneezing or when handling a package with contaminated hands - and how many/few viral particles "ingested" may cause an infection. I don't think one can simply conclude at all that "viruses will survive X days on cardboard/steel/plastic" because viral particles go through an exponential decay in the environment -- so more particles == more time to inactivate all the viruses, and the reverse. As far as I understand it, there's no predetermined "viable lifetime" (a sort of biologic clock and death) of a virus, the environment will just eventually destroy it and that point seems essentially random for an individual viral particle with different probability distributions on different surfaces. So if you start with a viral load that is higher, you will be able to detect viable viruses longer. So these numbers, e.g. detectable for 3 hours in aerosol don't mean anything unless the average human sneeze excretes as many viral particles as a "3-jet Collison nebulizer". If we excrete more than more viral particles remain viable longer and the detection threshold is reached later. If less, than those 3 hours don't apply.