9 ms·

Being infected isn't a binary thing. There is a big difference from swallowing 30 Coronavirus particles from touching your face to breathing in 300,000 from som

Being infected isn't a binary thing. There is a big difference from swallowing 30 Coronavirus particles from touching your face to breathing in 300,000 from someone coughing in your face. If you're young the first is probably a mild cold while the latter is a trip to the ICU. Part of bringing the virus under control is reducing the amount of particles people are exposed to so they have a better chance of fighting off the virus.

ArtTimeInvestor 5y ago
How do you know? It depends on how fast the virus population doubles. And how fast the immune system kicks in. If the virus population doubles every second then the person who swallowed 30 virus particles will be at 300,000 in just 14 seconds. If it doubles once per minute, it is 14 minutes. If it doubles once per hour, it is 14 hours. The question if that is a meaningful headstart depends on how fast the immune system reacts. And if it reacts faster to 300k viruses than to 30.
- corty 5y ago
  It doesn't only react faster, it will react differently. Up to a reaction called "sepsis" that can kill you even without the virus doing anything anymore. Research points to most covid complications being such (there are lots more, the immune system is the worst kind of spaghetti code you can imagine) massive immune reactions gone haywire. I'm not saying you are right or wrong. I'm saying that immune reactions aren't linear, straightforward, harmless or predictable. And that "more virus" usually isn't better.
  - berkes 5y ago
    As a type1 diabetic, I love the 'spagetticode' reference. Our biology is amazingly complex. And in a somewhat constant broken state. My immune system decided that crucial pieces of my own body, are dangerous invaders, and it then decided to attack it. The attack is ongoing, and successful: a crucial subroutine of me is being destroyed faster than another part of me can rewrite it.
- silverpepsi 5y ago
  >If the virus population doubles every second then the person who swallowed 30 virus particles will be at 300,000 in just 14 seconds That was also my intuitive response at the beginning of the pandemic. I assume one virus was plenty due to exponential growth. Having read every article I could in the past year, it's extremely rare to run across any details but: 1. I've read that scientists believe a coronavirus takes hundreds of viruses to successfully infect us. Not, for example, several dozen like some other viruses. 2. Next obvious question to me is, is this because one has to land on a lucky spot on the body and the rest somehow die before they can reproduce (so it's statistical odds that one virus gets the conditions it needs just like one sperm makes it to the egg)? Or can the body fight off a dozen or two dozen covid19 viruses so quickly that they never take hold? I only see two possibilities here. 3. If it is the latter, an answer I can't find anywhere, why did we need to waste so much time developing a vaccine? Wouldn't it be equally efficacious to introduce one virus to the body on day one, four on day two, and so on until immunity is achieved? Evidence of this possibility would be mixed in with the population they believe are asymptomatic, so unless researchers look for this they won't find it. (Basically a natural immunity hypothesis - based on repeated low viral count exposure.)
  - michaelmrose 5y ago
    A virus that doubled in a second would be perceived as a swarm that dissolved people before our eyes as it quickly ate the biomass of the planet. Think 2^86400 in one day. Fortunately it would need faster than light travel to keep replicating at that rate for long.
    - jamiek88 5y ago
      Why would it need ftl? Aren’t all the doublings local?
      - michaelmrose 5y ago
        I'm assuming it would consume all local mass shortly.
      - 5y ago
- Barrin92 5y ago
  Viral reproduction rate is not that fast. It's about 8 to 72 hours depending on the type of virus. This is why low viral load is generally associated with milder disease outcomes, the body has a significantly longer time to generate an immune response before the viral load becomes significant.
  - raphaelj 5y ago
    Parent was referring to the doubling rate. Cells produce more than one additional particule per reproduction cycle, so the doubling rate is lower than 8 to 72h.
- sateesh 5y ago
  Won't the immune system acts better when it gets infected by 30 (say) virus particles than swamped by 300k viruses (say).So my guess (as layman) is when infected with 30 viruses the growth might not be as uncontrollable (doubling per second). I think the virus load indeed matters too.
- bumbada 5y ago
  A very important thing is the topology of the infection. I had COVID last year and it progressed linearly over time, from the back of my nose(probably from a big water droplet I breathed)forwards(towards my nose) and downwards towards my lungs. I could measure the progress day after day. It progressed linearly because the breathing system is a duct. Like a fire needs a boundary to expand, a frontier. It is not 3D but 2 dimensional. You just can not do an exponential calculation, without taking into account the physical limits of the environment. Just before entering the lungs I did beat it. I coughed for a month or so,specially for the irritation in my glottis, but nothing serious. This year I got it again, the progress rate was very similar but my immune system reacted sooner. What is interesting is that I did not developed antibodies, my antibodies test were negative but the PCRs positives. This means that my T cells were already fighting the infection. That probably had something to do with living in China in the past and having developed immunity against SARS.
  - javagram 5y ago
    > That probably had something to do with living in China in the past and having developed immunity against SARS. Only about 8000 persons have been recorded to come down with SARS. Were you one of them with a diagnosed case of SARS (10% fatality rate)? The vast majority of residents in China would have no exposure to SARS.
  - thro1 5y ago
    > Just before entering the lungs I did beat it. How long it took / how fast it progressed from one drop almost to lungs (with what treatment)? Do you think this could have helped early in your case: Use of Povidone Iodine Nasal Spray.. https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3563092 https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3563092 (March 2020) or this: nasal rinse and mouthwash, Listerine Antiseptic https://doi.org/10.1002/jmv.26514 https://doi.org/10.1002/jmv.26514 if the virus landed on the throat ?
  - nopeBS 5y ago
    Alternative theory: you had something else for at least one of those reported illnesses, and your PCR test was a false positive. The rest is conjecture, anecdote, and speculation.
- 542354234235 5y ago
  This isn’t really accurate because it fails to take into account how infections work. Viruses don’t replicate like bacteria, so they don’t just double every X amount of time. They infect a cell and hijack the cell to produce copies (sometimes millions) of the virus until the cell exhausts itself and dies, bursting open and releasing all those copies of the virus. While this is happening, the body is attempting to fight this. What is particularly relevant are several of the varieties of T-cells, or killer cells. They are attempting to find cells infected with the virus and destroy them before they burst. While some copies of viruses escape cells as they are producing them, the overwhelming majority escape when it dies and bursts. What this means is that 30 viral particles do not become 300,000 in 14 seconds. Say that all 30 find cells and infect them, and T-cells destroy 50% before they burst. You have 15 cells that burst and release viruses to infect nearby cells. If you start with 300,000 infected cells, and T-cells destroy 50% before they burst, you have 150,000 cells that burst and release viruses to infect nearby cells. Low initial infections can often be well controlled and managed by the immune system in this way until antibodies are produced. High load infections can often spiral out of control due to so many initial cells being infected, the physical damage of higher numbers of killed cells, either burst or destroyed, and the high numbers outpacing the body’s ability. Of course this is also a simplification, but I think it demonstrates how initial viral load can have a big effect on outcome.
rscho 5y ago
You absolutely don't know that. Disease severity vs. contaminant load correlation is unknown.
- sgt101 5y ago
  You are right, but in the early phase of the pandemic this was raised by medics in the UK as a reason why some of them were dying. The pathology mentioned then was that a cytokine storm got kicked off in people with strong immune systems exposed to high load. This prompted changes in PPE for hospital staff - from light gear that would be worn in the face of flu patients (of whom, as we know some 1000's are hospitalised and die every year) to the space suit style gear that is now used in ICUs with COVID. If you are young and nursing a bunch of relatives at home it's reasonable to say that you are effectively exposed to ICU risks without ICU gear.
  - rscho 5y ago
    I work in an ICU. Bedside staff is equipped with PPE2. No space suit. I've spent months of my life wearing only a surgical mask in what is basically a COVID aquarium, with patients on non-invasive ventilation in open-space units spraying virus everywhere. Our staff case count of hospital-acquired infection is currently zero. So, I don't know what the ground truth is but it certainly seems like exposure is not the only factor.
    - sgt101 5y ago
      So - that's amazing to me. In the beginning of the pandemic the stats seemed to show that hospital staff were at significant risk. I think that this has faded from the numbers in the UK and my assumption was that this was because staff were now able to protect themselves with good PPE and vaccination.
- celticninja 5y ago
  https://www.bmj.com/content/371/bmj.m4763 https://www.bmj.com/content/371/bmj.m4763
squaredisk 5y ago
It makes logical sense, is there any study to support this

ArtTimeInvestor 5y ago

How do you know? It depends on how fast the virus population doubles. And how fast the immune system kicks in. If the virus population doubles every second then the person who swallowed 30 virus particles will be at 300,000 in just 14 seconds. If it doubles once per minute, it is 14 minutes. If it doubles once per hour, it is 14 hours. The question if that is a meaningful headstart depends on how fast the immune system reacts. And if it reacts faster to 300k viruses than to 30.

corty 5y ago
It doesn't only react faster, it will react differently. Up to a reaction called "sepsis" that can kill you even without the virus doing anything anymore. Research points to most covid complications being such (there are lots more, the immune system is the worst kind of spaghetti code you can imagine) massive immune reactions gone haywire. I'm not saying you are right or wrong. I'm saying that immune reactions aren't linear, straightforward, harmless or predictable. And that "more virus" usually isn't better.
- berkes 5y ago
  As a type1 diabetic, I love the 'spagetticode' reference. Our biology is amazingly complex. And in a somewhat constant broken state. My immune system decided that crucial pieces of my own body, are dangerous invaders, and it then decided to attack it. The attack is ongoing, and successful: a crucial subroutine of me is being destroyed faster than another part of me can rewrite it.
silverpepsi 5y ago
>If the virus population doubles every second then the person who swallowed 30 virus particles will be at 300,000 in just 14 seconds That was also my intuitive response at the beginning of the pandemic. I assume one virus was plenty due to exponential growth. Having read every article I could in the past year, it's extremely rare to run across any details but: 1. I've read that scientists believe a coronavirus takes hundreds of viruses to successfully infect us. Not, for example, several dozen like some other viruses. 2. Next obvious question to me is, is this because one has to land on a lucky spot on the body and the rest somehow die before they can reproduce (so it's statistical odds that one virus gets the conditions it needs just like one sperm makes it to the egg)? Or can the body fight off a dozen or two dozen covid19 viruses so quickly that they never take hold? I only see two possibilities here. 3. If it is the latter, an answer I can't find anywhere, why did we need to waste so much time developing a vaccine? Wouldn't it be equally efficacious to introduce one virus to the body on day one, four on day two, and so on until immunity is achieved? Evidence of this possibility would be mixed in with the population they believe are asymptomatic, so unless researchers look for this they won't find it. (Basically a natural immunity hypothesis - based on repeated low viral count exposure.)
- michaelmrose 5y ago
  A virus that doubled in a second would be perceived as a swarm that dissolved people before our eyes as it quickly ate the biomass of the planet. Think 2^86400 in one day. Fortunately it would need faster than light travel to keep replicating at that rate for long.
  - jamiek88 5y ago
    Why would it need ftl? Aren’t all the doublings local?
    - michaelmrose 5y ago
      I'm assuming it would consume all local mass shortly.
    - 5y ago
Barrin92 5y ago
Viral reproduction rate is not that fast. It's about 8 to 72 hours depending on the type of virus. This is why low viral load is generally associated with milder disease outcomes, the body has a significantly longer time to generate an immune response before the viral load becomes significant.
- raphaelj 5y ago
  Parent was referring to the doubling rate. Cells produce more than one additional particule per reproduction cycle, so the doubling rate is lower than 8 to 72h.
sateesh 5y ago
Won't the immune system acts better when it gets infected by 30 (say) virus particles than swamped by 300k viruses (say).So my guess (as layman) is when infected with 30 viruses the growth might not be as uncontrollable (doubling per second). I think the virus load indeed matters too.
bumbada 5y ago
A very important thing is the topology of the infection. I had COVID last year and it progressed linearly over time, from the back of my nose(probably from a big water droplet I breathed)forwards(towards my nose) and downwards towards my lungs. I could measure the progress day after day. It progressed linearly because the breathing system is a duct. Like a fire needs a boundary to expand, a frontier. It is not 3D but 2 dimensional. You just can not do an exponential calculation, without taking into account the physical limits of the environment. Just before entering the lungs I did beat it. I coughed for a month or so,specially for the irritation in my glottis, but nothing serious. This year I got it again, the progress rate was very similar but my immune system reacted sooner. What is interesting is that I did not developed antibodies, my antibodies test were negative but the PCRs positives. This means that my T cells were already fighting the infection. That probably had something to do with living in China in the past and having developed immunity against SARS.
- javagram 5y ago
  > That probably had something to do with living in China in the past and having developed immunity against SARS. Only about 8000 persons have been recorded to come down with SARS. Were you one of them with a diagnosed case of SARS (10% fatality rate)? The vast majority of residents in China would have no exposure to SARS.
- thro1 5y ago
  > Just before entering the lungs I did beat it. How long it took / how fast it progressed from one drop almost to lungs (with what treatment)? Do you think this could have helped early in your case: Use of Povidone Iodine Nasal Spray.. https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3563092 https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3563092 (March 2020) or this: nasal rinse and mouthwash, Listerine Antiseptic https://doi.org/10.1002/jmv.26514 https://doi.org/10.1002/jmv.26514 if the virus landed on the throat ?
- nopeBS 5y ago
  Alternative theory: you had something else for at least one of those reported illnesses, and your PCR test was a false positive. The rest is conjecture, anecdote, and speculation.
542354234235 5y ago
This isn’t really accurate because it fails to take into account how infections work. Viruses don’t replicate like bacteria, so they don’t just double every X amount of time. They infect a cell and hijack the cell to produce copies (sometimes millions) of the virus until the cell exhausts itself and dies, bursting open and releasing all those copies of the virus. While this is happening, the body is attempting to fight this. What is particularly relevant are several of the varieties of T-cells, or killer cells. They are attempting to find cells infected with the virus and destroy them before they burst. While some copies of viruses escape cells as they are producing them, the overwhelming majority escape when it dies and bursts. What this means is that 30 viral particles do not become 300,000 in 14 seconds. Say that all 30 find cells and infect them, and T-cells destroy 50% before they burst. You have 15 cells that burst and release viruses to infect nearby cells. If you start with 300,000 infected cells, and T-cells destroy 50% before they burst, you have 150,000 cells that burst and release viruses to infect nearby cells. Low initial infections can often be well controlled and managed by the immune system in this way until antibodies are produced. High load infections can often spiral out of control due to so many initial cells being infected, the physical damage of higher numbers of killed cells, either burst or destroyed, and the high numbers outpacing the body’s ability. Of course this is also a simplification, but I think it demonstrates how initial viral load can have a big effect on outcome.

rscho 5y ago

You absolutely don't know that. Disease severity vs. contaminant load correlation is unknown.

sgt101 5y ago
You are right, but in the early phase of the pandemic this was raised by medics in the UK as a reason why some of them were dying. The pathology mentioned then was that a cytokine storm got kicked off in people with strong immune systems exposed to high load. This prompted changes in PPE for hospital staff - from light gear that would be worn in the face of flu patients (of whom, as we know some 1000's are hospitalised and die every year) to the space suit style gear that is now used in ICUs with COVID. If you are young and nursing a bunch of relatives at home it's reasonable to say that you are effectively exposed to ICU risks without ICU gear.
- rscho 5y ago
  I work in an ICU. Bedside staff is equipped with PPE2. No space suit. I've spent months of my life wearing only a surgical mask in what is basically a COVID aquarium, with patients on non-invasive ventilation in open-space units spraying virus everywhere. Our staff case count of hospital-acquired infection is currently zero. So, I don't know what the ground truth is but it certainly seems like exposure is not the only factor.
  - sgt101 5y ago
    So - that's amazing to me. In the beginning of the pandemic the stats seemed to show that hospital staff were at significant risk. I think that this has faded from the numbers in the UK and my assumption was that this was because staff were now able to protect themselves with good PPE and vaccination.
celticninja 5y ago
https://www.bmj.com/content/371/bmj.m4763 https://www.bmj.com/content/371/bmj.m4763

squaredisk 5y ago

It makes logical sense, is there any study to support this