11 ms·

Substantial undocumented infection facilitates rapid dissemination of SARS-CoV2

139 points by mcone 7y ago

joe_the_user 7y ago
The article is interesting but it seems to be just a mathematical model rather than a biological study actually finding and studying people who had undocumented infections. I know they have found people like that but I'd still be leery about going from data to a pronouncement since I assume the data just isn't extensive or reliable.
- gwbas1c 7y ago
  But you need actual testing in order to get real data
  - Taek 7y ago
    South Korea has done a good job of getting enough tests done to have meaningful data
    - iso947 7y ago
      Self selecting tests. Need the types of control data that polling companies use.
      - akiselev 7y ago
        South Korea has been doing extensive contact tracing and quarantining from the start. They're as close to a statistical sample as we're going to get until large scale random antibody tests are done. At best the US could probably fit it into the census process.
        spookthesunset 7y ago
        Until you get a good bit of random antibody tests, it is all speculation. Nobody really knows how widespread this thing is, what its actual death rate is or anything else. I personally wouldn't be surprised to learn the number of people who had it or have it now is hundreds of times higher than the "confirmed cases". I would also speculate that this virus has been in wide circulation for months now. But my guess is as good as anybody else. Until we get actual, statistically valid high quality data.... all we have is speculation. I sure hope we are making the right call shutting things down as much as we are. People have to remember that there are serious physical health consequences to the actions being taken. Suicide rates will climb, alcoholism & addiction will jump, crime will go up, etc. A few weeks of this kind of economic pause is one thing but at some point in the very near future people are going to want to know what the end game is.
        drivebycomment 7y ago
        As of today, Korea reports 274K tested, with 3.2% infected out of that. They also show strong signs of containment. Those two datapoints indicate that they didn't miss many infected cases.
        spookthesunset 7y ago
        Does that testing include people who had it before and just have antibodies? Or just active cases?
        dboreham 7y ago
        There is no deployed serological test at present.
  - m0zg 7y ago
    People overestimate the accuracy of this test as well. There's a doctor in Seattle who tested negative, and a few days later ended up in the ICU. He's currently in the process of dying. Just because the test says "no virus" (or vice versa) does not mean you're free and clear. Especially early in the disease cycle RT-PCR is known to produce false negatives sometimes.
- btilly 7y ago
  The Seattle flu study is an example of what you want. As https://komonews.com/news/coronavirus/seattle-flu-study-allegedly-tested-samples-for-covid-19-against-federal-state-guidelines https://komonews.com/news/coronavirus/seattle-flu-study-alle... shows, the USA was refusing to test Americans in Seattle while COVID-19 was actually spreading. When the Seattle flu study tested they found that it had already been locally spreading for weeks. And in fact most people who think that they have COVID-19 in the USA are unable to verify whether or not they have it.
taeric 7y ago
This feels mixed. If true, it is more than just explaining how rapidly it spread, as the spread happened months ago. It also raises the question of why is it so severe some places, but less so many others?
- SpicyLemonZest 7y ago
  The implication would be that, in the places where it's severe, transmission is actually completely uncontrolled and statistics fail to show it because of testing problems. I think Iran is the place to watch - there are other reasons to believe (such as the number of politicians infected) that the virus is there in large numbers everywhere.
  - roywiggins 7y ago
    They were spotted (from orbit) digging mass graves, so. Not optimistic.
    - nitrogen 7y ago
      Do you have a link?
      - belltaco 7y ago
        https://www.dailymotion.com/video/x7spz74 https://www.dailymotion.com/video/x7spz74
      - roywiggins 7y ago
        https://www.washingtonpost.com/graphics/2020/world/iran-coronavirus-outbreak-graves/?itid=sf_world https://www.washingtonpost.com/graphics/2020/world/iran-coro...
    - majos 7y ago
      The “from orbit” part is a little misleading I think. You can also see individual cars, down to their passenger windows, from orbit in the referenced photos. The photos are pretty detailed.
nmca 7y ago
Does this mean the mortality rate is, approximately, 10x less than currently estimated? (86% of cases unreported, eg about 1 in 10 reported, assume that number of unreported fatal cases is 0) Edit: closer reading suggests the optimism is sadly unwarranted, the headline under-reporting number of 86% is from the early pre-travel ban model, post-travel-ban estimates give a 65% detection rate, combined with the increased number of cases in this later period this implies that naive mortality estimates are more like 2x off than 10x off.
- nmca 7y ago
  I have been considering other ways to estimate this, and looked at numbers for Singapore, which I believe has particularly strict testing. They show a much lower mortality rate than the other estimates I have heard, but only at n=250. This may also be confounded by wealth/healthcare quality. Does anyone have a decent model of the mortality rate?
- arcticbull 7y ago
  Yeah so, what the data has been pointing to the whole time.
  - cycrutchfield 7y ago
    Which data?
    - arcticbull 7y ago
      Well the cruise ship showed 55% of folks being asymptomatic and 80% of the remainder have mild flu like symptoms, and with an R0 of 2-3 for every person you do see get tested positive, there’s a mountain of folks spreading it without symptoms. This also explains why Korea’s [edit: case fatality] rate is so low and so correlated with their high incidence of testing. I wouldn’t be surprised if the majority of us have already had it. There’s a decent shot this all amounts to a big ol nothing burger.
      - 7y ago
deleted 7y ago
[deleted]

139 points by mcone 7y ago

The article is interesting but it seems to be just a mathematical model rather than a biological study actually finding and studying people who had undocumented infections. I know they have found people like that but I'd still be leery about going from data to a pronouncement since I assume the data just isn't extensive or reliable.

gwbas1c 7y ago
But you need actual testing in order to get real data
- Taek 7y ago
  South Korea has done a good job of getting enough tests done to have meaningful data
  - iso947 7y ago
    Self selecting tests. Need the types of control data that polling companies use.
    - akiselev 7y ago
      South Korea has been doing extensive contact tracing and quarantining from the start. They're as close to a statistical sample as we're going to get until large scale random antibody tests are done. At best the US could probably fit it into the census process.
      - spookthesunset 7y ago
        Until you get a good bit of random antibody tests, it is all speculation. Nobody really knows how widespread this thing is, what its actual death rate is or anything else. I personally wouldn't be surprised to learn the number of people who had it or have it now is hundreds of times higher than the "confirmed cases". I would also speculate that this virus has been in wide circulation for months now. But my guess is as good as anybody else. Until we get actual, statistically valid high quality data.... all we have is speculation. I sure hope we are making the right call shutting things down as much as we are. People have to remember that there are serious physical health consequences to the actions being taken. Suicide rates will climb, alcoholism & addiction will jump, crime will go up, etc. A few weeks of this kind of economic pause is one thing but at some point in the very near future people are going to want to know what the end game is.
        drivebycomment 7y ago
        As of today, Korea reports 274K tested, with 3.2% infected out of that. They also show strong signs of containment. Those two datapoints indicate that they didn't miss many infected cases.
        spookthesunset 7y ago
        Does that testing include people who had it before and just have antibodies? Or just active cases?
        dboreham 7y ago
        There is no deployed serological test at present.
- m0zg 7y ago
  People overestimate the accuracy of this test as well. There's a doctor in Seattle who tested negative, and a few days later ended up in the ICU. He's currently in the process of dying. Just because the test says "no virus" (or vice versa) does not mean you're free and clear. Especially early in the disease cycle RT-PCR is known to produce false negatives sometimes.
btilly 7y ago
The Seattle flu study is an example of what you want. As https://komonews.com/news/coronavirus/seattle-flu-study-allegedly-tested-samples-for-covid-19-against-federal-state-guidelines https://komonews.com/news/coronavirus/seattle-flu-study-alle... shows, the USA was refusing to test Americans in Seattle while COVID-19 was actually spreading. When the Seattle flu study tested they found that it had already been locally spreading for weeks. And in fact most people who think that they have COVID-19 in the USA are unable to verify whether or not they have it.

taeric 7y ago

This feels mixed. If true, it is more than just explaining how rapidly it spread, as the spread happened months ago. It also raises the question of why is it so severe some places, but less so many others?

SpicyLemonZest 7y ago
The implication would be that, in the places where it's severe, transmission is actually completely uncontrolled and statistics fail to show it because of testing problems. I think Iran is the place to watch - there are other reasons to believe (such as the number of politicians infected) that the virus is there in large numbers everywhere.
- roywiggins 7y ago
  They were spotted (from orbit) digging mass graves, so. Not optimistic.
  - nitrogen 7y ago
    Do you have a link?
    - belltaco 7y ago
      https://www.dailymotion.com/video/x7spz74 https://www.dailymotion.com/video/x7spz74
    - roywiggins 7y ago
      https://www.washingtonpost.com/graphics/2020/world/iran-coronavirus-outbreak-graves/?itid=sf_world https://www.washingtonpost.com/graphics/2020/world/iran-coro...
  - majos 7y ago
    The “from orbit” part is a little misleading I think. You can also see individual cars, down to their passenger windows, from orbit in the referenced photos. The photos are pretty detailed.

nmca 7y ago

Does this mean the mortality rate is, approximately, 10x less than currently estimated? (86% of cases unreported, eg about 1 in 10 reported, assume that number of unreported fatal cases is 0) Edit: closer reading suggests the optimism is sadly unwarranted, the headline under-reporting number of 86% is from the early pre-travel ban model, post-travel-ban estimates give a 65% detection rate, combined with the increased number of cases in this later period this implies that naive mortality estimates are more like 2x off than 10x off.

nmca 7y ago
I have been considering other ways to estimate this, and looked at numbers for Singapore, which I believe has particularly strict testing. They show a much lower mortality rate than the other estimates I have heard, but only at n=250. This may also be confounded by wealth/healthcare quality. Does anyone have a decent model of the mortality rate?
arcticbull 7y ago
Yeah so, what the data has been pointing to the whole time.
- cycrutchfield 7y ago
  Which data?
  - arcticbull 7y ago
    Well the cruise ship showed 55% of folks being asymptomatic and 80% of the remainder have mild flu like symptoms, and with an R0 of 2-3 for every person you do see get tested positive, there’s a mountain of folks spreading it without symptoms. This also explains why Korea’s [edit: case fatality] rate is so low and so correlated with their high incidence of testing. I wouldn’t be surprised if the majority of us have already had it. There’s a decent shot this all amounts to a big ol nothing burger.
    - 7y ago

deleted 7y ago

[deleted]