5 ms·

There is a large number of asymptotic cases which is quite encouraging. In their preliminary conclusion they write: "By adhering to strict hygiene measures it

by Tepix 7y ago

There is a large number of asymptotic cases which is quite encouraging. In their preliminary conclusion they write: "By adhering to strict hygiene measures it is to be expected that the virus concentration of an infected individual can be reduced to the point that the illness manifests more mildly, with simultaneous development of an immunity." I wonder how they came to that conclusion. It would be great if it turns out to be correct.

point78 7y ago
So wash your hands and gargle and your symptoms are mild?
- rooam-dev 7y ago
  Interesting indeed, perhaps by reducing the quantity of virus we give more time to our body to prepare for the "invasion"?
  - Tepix 7y ago
    That's a theory I've heard before. I don't remember where, unfortunately. Does anyone have a source? The basic theory is that if you catch the virus, you want to have it in your nose first so your body has time to start a response before it reaches your lungs. If you get a large dose into your lungs at the start (perhaps because you work at a hospital with insufficient PPE) it's less likely to be mild.
    - usrusr 7y ago
      > The basic theory is that if you catch the virus, you want to have it in your nose first so your body has time to start a response before it reaches your lungs. That's a thought that has crossed my mind before: if it's better the farther up in the respiratory system the initial infection happens, then all that hand washing might be a bad idea, at least for the personal outcome. It depends a lot on wether you expect the full wave to eventually roll through until herd immunity or if you expect it to be stopped early, either by continued distancing until it's starved our by a vaccine.
      - coldtea 7y ago
        >That's a thought that has crossed my mind before: if it's better the farther up in the respiratory system the initial infection happens, then all that hand washing might be a bad idea, at least for the personal outcome. Huh? How does that figure? Hand washing will means less (or no) virii in your nose/mouth. So, isn't it (a) good in itself, and (b) totally orthogonal to the infection happening "farther up in the respiratory system" (aside the positive, that if it happens and is further up, it will also be less viral content)
        usrusr 7y ago
        > Huh? How does that figure? Hand washing will means less (or no) virii in your nose/mouth. If you make "first contact" by inhaling tiny droplets it's possible that they will make landfall right down in the lungs, whereas an infection from dirty fingers is guaranteed to start in the nose/mouth area and will already be an immune system project while it works it's way deeper down. Still worse than not getting infected at all, but if you assume that it will eventually hit you anyways, easing into the infection via the nose would surely be preferable to starting in the lungs where it's actually dangerous. The reverse of this would be accumulating an infective dose from the leakage amount allowed through by PPE while working in extreme exposure. I doubt that there is empirical data regarding viruses, but everything we've learned about particulate emissions suggests that smaller particles reach deeper into the lungs. So it seems quite convincing to me that people who do fall ill despite PPE fall ill harder. Might explain the prominent medical worker deaths.
        Aeolun 7y ago
        If you stick your unwashed vingers in your nose a few times a day then maybe that will cause you to get sick instead of someone sneezing in your face?
  - gwd 7y ago
    I've heard that as well. Basically, the spread of the virus inside your body is exponential too, whereas the immune system's response time will be fairly static. So if you're exposed to a little, the immune system has time to respond before the infection gets out of control; if you're exposed to a large amount, by the time the immune system starts to respond, the virus is already widespread in your system.
    - rooam-dev 7y ago
      Cool. Like a poor man's vaccine. Nature is amazing.
    - maxerickson 7y ago
      Why wouldn't it be the other way around? If the virus replicates very fast, people with minimum infectious doses have a couple replication generations of extra time. If the virus replicates more slowly, a large infectious dose would have the same impact as multiple replication generations. I'm not asserting the above is what happens, I'm asking the question.
      - kortex 7y ago
        Viral load V, dV/dt = rV. This loosely solves to V = a*exp(rt). The bigger your V0, the faster the initial rate of increase. The Vmin to be detected by your immune system is small. You want the most time between Vdetected and Vdanger.
        netjiro 7y ago
        There is an interesting accidental study about this regarding norovirus. (Back in 2014 I think, not the 2017 Tennessee thanksgiving event) Some guy vomited in a restaurant. Then you can clearly model the time from exposure to symptoms in everyone else based on how far away they were when the guy vomited. Though in this case the viral exposure was very high for everyone in the restaurant.
        maxerickson 7y ago
        My question is about how much r matters. For influenza, each infected cell apparently infects ~22 other cells: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1563736/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1563736/ So in 2 generations you have 500x the virus. If it were 'less' exponential, and each cell only infected, say, 5 others, then you get to 500x late in the 4th generation. In a cartoon example where a low exposure leads to 1 infected cell and a high exposure leads to 500 infected cells, the low exposure matters more if the reproductive factor is lower.
- oxymoran 7y ago
  I couldn’t get tested so not 100% that I actually had covid but as soon as I started having some symptoms I started gargling with diluted hydrogen peroxide and rinsing my sinuses with a strong saline solution. I can’t see how this would hurt and why this isn’t recommended given that the virus replicates in the nose and throat.
  - fsh 7y ago
    The viruses are replicating inside your cells. You can't just "disinfect" living tissue without killing it. There is a reason why medicine relies on evidence and does not recommend whatever random "treatment" someone came up with.
    - coldtea 7y ago
      >The viruses are replicating inside your cells. You can't just "disinfect" living tissue without killing it. Err, you can wash your hands, and it will "disinfect them". And if the viral content is still in your nose/mouth/neck, you can dissinfect that too to some degree. So, there's that...
      - fsh 7y ago
        You can wash or disinfect your hands because the top layer of the skin is not living tissue.
        coldtea 7y ago
        And you disinfect your mouth because disinfecting doesn't mean killing your mouth/tongue tissue. There are several mouthwashes on the market with antibacterial/antiviral properties, dentists do the same, etc...
  - papaf 7y ago
    I couldn’t get tested so not 100% In Bavaria they are only testing people with symptoms and the positive rate is around 10% [1]. Everybody thinks they have it but the symptoms could also be down to a cold. I am not pointing this statistic out to prove you wrong -- I just find it interesting. [1] https://www.lgl.bayern.de/gesundheit/infektionsschutz/infektionskrankheiten_a_z/coronavirus/karte_coronavirus/index.htm https://www.lgl.bayern.de/gesundheit/infektionsschutz/infekt... and search on the page for 'Laboruntersuchungen'. The left axis is number of tests and the right axis is percentage of positive tests.
- chippy 7y ago
  Another anecdote: someone online who works in a virus lab doing other stuff said that if you are ill, have a shower twice a day and rinse mouth with mouthwash to reduce viral load. If you need to go out, when you come back, remove all clothes and wash and then have a shower.
- odiroot 7y ago
  I wonder how much of the virus is enough to "catch it"? One droplet? 100 droplets?
  - netjiro 7y ago
    This is unknown, it's individual, and varies over orders of magnitude between different diseases.
benschulz 7y ago
I think it is based on the idea that staying as close as possible to the infectious dose leads to a better outcome/less severe progression. The infectious dose being "the average number of viral particles needed to establish an infection"[1]. [1]: https://www.newscientist.com/article/2238819-does-a-high-viral-load-or-infectious-dose-make-covid-19-worse/ https://www.newscientist.com/article/2238819-does-a-high-vir...
- chippy 7y ago
  So the studies show that there is no correlation between viral load and severity of symptoms. One study showed there was a correlation between amount of virus in the nose and severity of symptoms. No studies have looked at various levels of initial dose (does initial dose correlates to viral load?) I imagine such a thing is very hard to measure.
  - drclau 7y ago
    Can’t remember right now where I heard, it was in a podcast. Will return with the information if/when I find it. An epidemiologist said that there is correlation between the viral load and the severity of the resulting illness in studies on mice. He also said something that surprised me, namely that the mechanism involved is unknown. It seems fairly obvious that it has to do with the exponential growth of the pathogen inside the body.
- jpxw 7y ago
  There are also rumours (and I stress, rumours) that healthcare workers are getting more severe disease due to being infected with a higher infectious load. This would also fit with this theory.
  - drclau 7y ago
    Healthcare workers are also overworked nearly everywhere, due to the pandemic, which means their immunity is possibly weakened too.
Maarten88 7y ago
Yes that conclusion also struck me, there is nothing in the text that seems to support this. But maybe there are observations pointing to this? If true, would it be possible to infect yourself with a tiny concentration of the virus, then isolate, and expect mild illness followed by immunity?
usrusr 7y ago
Makes me wonder if it might be possible to deliberately infect body regions where the virus has a low chance of reaching the lung. Could the virus populate (until sufficient immune reaction) the lower intestine if put there, and not spread elsewhere due to the unambiguously directed flow down there (as opposed to bidirectional flow in the respiratory system) or would it be transmitted elsewhere nonetheless through the blood stream? Is this something that can and is checked with animal models?
s9w 7y ago
He spoke more about that than was written. It seems to be the case that the viral load of the point of infection is a major factor in determining how bad it gets. Therefore low-load infections are actually desirably since those are the asymptomatic cases.
- Aeolun 7y ago
  Isn’t that a super easy vaccine then? Insert super low load, stay home for two weeks, and you have been immunized.
  - s9w 7y ago
    That was actually my reaction, too. But I don't think that will go through any ethics commission. Also the immunity will also last for about a year he said. Which is mind-boggling in itself.
    - netjiro 7y ago
      Low viral load exposure will likely increase the chances of a milder progression. But that's a very risky gamble. Will still be way too lethal. It is still unknown if this effect is insignificantly small. Instead we could grow lots of viral particles. Irradiate them to certain death. Then use it to repeatedly challenge the immune system over a long period. Very expensive and nowhere near as effective or reliable as a proper vaccine, but would induce some level of resistance in a fraction of the population.
- mannykannot 7y ago
  Can this study really be expected to provide data on the viral load of the point of infection, and at the time of infection? (I would guess that measurements of the distribution of the viral load, after the infection has progressed for some time, would be dependent on how the person's imune system is responding, and conseqently not good evidence for this proposition.) If not, then is this a well-established feature of respiratory virus infections? In other words, to what extent is this claim backed by evidence? And is it evidence from studying C19 specifically?

by Tepix 7y ago

point78 7y ago

So wash your hands and gargle and your symptoms are mild?

rooam-dev 7y ago
Interesting indeed, perhaps by reducing the quantity of virus we give more time to our body to prepare for the "invasion"?
- Tepix 7y ago
  That's a theory I've heard before. I don't remember where, unfortunately. Does anyone have a source? The basic theory is that if you catch the virus, you want to have it in your nose first so your body has time to start a response before it reaches your lungs. If you get a large dose into your lungs at the start (perhaps because you work at a hospital with insufficient PPE) it's less likely to be mild.
  - usrusr 7y ago
    > The basic theory is that if you catch the virus, you want to have it in your nose first so your body has time to start a response before it reaches your lungs. That's a thought that has crossed my mind before: if it's better the farther up in the respiratory system the initial infection happens, then all that hand washing might be a bad idea, at least for the personal outcome. It depends a lot on wether you expect the full wave to eventually roll through until herd immunity or if you expect it to be stopped early, either by continued distancing until it's starved our by a vaccine.
    - coldtea 7y ago
      >That's a thought that has crossed my mind before: if it's better the farther up in the respiratory system the initial infection happens, then all that hand washing might be a bad idea, at least for the personal outcome. Huh? How does that figure? Hand washing will means less (or no) virii in your nose/mouth. So, isn't it (a) good in itself, and (b) totally orthogonal to the infection happening "farther up in the respiratory system" (aside the positive, that if it happens and is further up, it will also be less viral content)
      - usrusr 7y ago
        > Huh? How does that figure? Hand washing will means less (or no) virii in your nose/mouth. If you make "first contact" by inhaling tiny droplets it's possible that they will make landfall right down in the lungs, whereas an infection from dirty fingers is guaranteed to start in the nose/mouth area and will already be an immune system project while it works it's way deeper down. Still worse than not getting infected at all, but if you assume that it will eventually hit you anyways, easing into the infection via the nose would surely be preferable to starting in the lungs where it's actually dangerous. The reverse of this would be accumulating an infective dose from the leakage amount allowed through by PPE while working in extreme exposure. I doubt that there is empirical data regarding viruses, but everything we've learned about particulate emissions suggests that smaller particles reach deeper into the lungs. So it seems quite convincing to me that people who do fall ill despite PPE fall ill harder. Might explain the prominent medical worker deaths.
      - Aeolun 7y ago
        If you stick your unwashed vingers in your nose a few times a day then maybe that will cause you to get sick instead of someone sneezing in your face?
- gwd 7y ago
  I've heard that as well. Basically, the spread of the virus inside your body is exponential too, whereas the immune system's response time will be fairly static. So if you're exposed to a little, the immune system has time to respond before the infection gets out of control; if you're exposed to a large amount, by the time the immune system starts to respond, the virus is already widespread in your system.
  - rooam-dev 7y ago
    Cool. Like a poor man's vaccine. Nature is amazing.
  - maxerickson 7y ago
    Why wouldn't it be the other way around? If the virus replicates very fast, people with minimum infectious doses have a couple replication generations of extra time. If the virus replicates more slowly, a large infectious dose would have the same impact as multiple replication generations. I'm not asserting the above is what happens, I'm asking the question.
    - kortex 7y ago
      Viral load V, dV/dt = rV. This loosely solves to V = a*exp(rt). The bigger your V0, the faster the initial rate of increase. The Vmin to be detected by your immune system is small. You want the most time between Vdetected and Vdanger.
      - netjiro 7y ago
        There is an interesting accidental study about this regarding norovirus. (Back in 2014 I think, not the 2017 Tennessee thanksgiving event) Some guy vomited in a restaurant. Then you can clearly model the time from exposure to symptoms in everyone else based on how far away they were when the guy vomited. Though in this case the viral exposure was very high for everyone in the restaurant.
      - maxerickson 7y ago
        My question is about how much r matters. For influenza, each infected cell apparently infects ~22 other cells: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1563736/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1563736/ So in 2 generations you have 500x the virus. If it were 'less' exponential, and each cell only infected, say, 5 others, then you get to 500x late in the 4th generation. In a cartoon example where a low exposure leads to 1 infected cell and a high exposure leads to 500 infected cells, the low exposure matters more if the reproductive factor is lower.
oxymoran 7y ago
I couldn’t get tested so not 100% that I actually had covid but as soon as I started having some symptoms I started gargling with diluted hydrogen peroxide and rinsing my sinuses with a strong saline solution. I can’t see how this would hurt and why this isn’t recommended given that the virus replicates in the nose and throat.
- fsh 7y ago
  The viruses are replicating inside your cells. You can't just "disinfect" living tissue without killing it. There is a reason why medicine relies on evidence and does not recommend whatever random "treatment" someone came up with.
  - coldtea 7y ago
    >The viruses are replicating inside your cells. You can't just "disinfect" living tissue without killing it. Err, you can wash your hands, and it will "disinfect them". And if the viral content is still in your nose/mouth/neck, you can dissinfect that too to some degree. So, there's that...
    - fsh 7y ago
      You can wash or disinfect your hands because the top layer of the skin is not living tissue.
      - coldtea 7y ago
        And you disinfect your mouth because disinfecting doesn't mean killing your mouth/tongue tissue. There are several mouthwashes on the market with antibacterial/antiviral properties, dentists do the same, etc...
- papaf 7y ago
  I couldn’t get tested so not 100% In Bavaria they are only testing people with symptoms and the positive rate is around 10% [1]. Everybody thinks they have it but the symptoms could also be down to a cold. I am not pointing this statistic out to prove you wrong -- I just find it interesting. [1] https://www.lgl.bayern.de/gesundheit/infektionsschutz/infektionskrankheiten_a_z/coronavirus/karte_coronavirus/index.htm https://www.lgl.bayern.de/gesundheit/infektionsschutz/infekt... and search on the page for 'Laboruntersuchungen'. The left axis is number of tests and the right axis is percentage of positive tests.
chippy 7y ago
Another anecdote: someone online who works in a virus lab doing other stuff said that if you are ill, have a shower twice a day and rinse mouth with mouthwash to reduce viral load. If you need to go out, when you come back, remove all clothes and wash and then have a shower.
odiroot 7y ago
I wonder how much of the virus is enough to "catch it"? One droplet? 100 droplets?
- netjiro 7y ago
  This is unknown, it's individual, and varies over orders of magnitude between different diseases.

benschulz 7y ago

I think it is based on the idea that staying as close as possible to the infectious dose leads to a better outcome/less severe progression. The infectious dose being "the average number of viral particles needed to establish an infection"[1]. [1]: https://www.newscientist.com/article/2238819-does-a-high-viral-load-or-infectious-dose-make-covid-19-worse/ https://www.newscientist.com/article/2238819-does-a-high-vir...

chippy 7y ago
So the studies show that there is no correlation between viral load and severity of symptoms. One study showed there was a correlation between amount of virus in the nose and severity of symptoms. No studies have looked at various levels of initial dose (does initial dose correlates to viral load?) I imagine such a thing is very hard to measure.
- drclau 7y ago
  Can’t remember right now where I heard, it was in a podcast. Will return with the information if/when I find it. An epidemiologist said that there is correlation between the viral load and the severity of the resulting illness in studies on mice. He also said something that surprised me, namely that the mechanism involved is unknown. It seems fairly obvious that it has to do with the exponential growth of the pathogen inside the body.
jpxw 7y ago
There are also rumours (and I stress, rumours) that healthcare workers are getting more severe disease due to being infected with a higher infectious load. This would also fit with this theory.
- drclau 7y ago
  Healthcare workers are also overworked nearly everywhere, due to the pandemic, which means their immunity is possibly weakened too.

Maarten88 7y ago

Yes that conclusion also struck me, there is nothing in the text that seems to support this. But maybe there are observations pointing to this? If true, would it be possible to infect yourself with a tiny concentration of the virus, then isolate, and expect mild illness followed by immunity?

usrusr 7y ago

Makes me wonder if it might be possible to deliberately infect body regions where the virus has a low chance of reaching the lung. Could the virus populate (until sufficient immune reaction) the lower intestine if put there, and not spread elsewhere due to the unambiguously directed flow down there (as opposed to bidirectional flow in the respiratory system) or would it be transmitted elsewhere nonetheless through the blood stream? Is this something that can and is checked with animal models?

s9w 7y ago

He spoke more about that than was written. It seems to be the case that the viral load of the point of infection is a major factor in determining how bad it gets. Therefore low-load infections are actually desirably since those are the asymptomatic cases.

Aeolun 7y ago
Isn’t that a super easy vaccine then? Insert super low load, stay home for two weeks, and you have been immunized.
- s9w 7y ago
  That was actually my reaction, too. But I don't think that will go through any ethics commission. Also the immunity will also last for about a year he said. Which is mind-boggling in itself.
  - netjiro 7y ago
    Low viral load exposure will likely increase the chances of a milder progression. But that's a very risky gamble. Will still be way too lethal. It is still unknown if this effect is insignificantly small. Instead we could grow lots of viral particles. Irradiate them to certain death. Then use it to repeatedly challenge the immune system over a long period. Very expensive and nowhere near as effective or reliable as a proper vaccine, but would induce some level of resistance in a fraction of the population.
mannykannot 7y ago
Can this study really be expected to provide data on the viral load of the point of infection, and at the time of infection? (I would guess that measurements of the distribution of the viral load, after the infection has progressed for some time, would be dependent on how the person's imune system is responding, and conseqently not good evidence for this proposition.) If not, then is this a well-established feature of respiratory virus infections? In other words, to what extent is this claim backed by evidence? And is it evidence from studying C19 specifically?