19 ms·

How many microbes does it take to make you sick?

145 points by meany 3y ago

3seashells 3y ago
A fascinating thing is that you can catch a infection early. If you know you have been exposed and time it right you can induce a artificial fever via sauna or steam bath. This catches the whole infection ahead of the curve and shortens reconvalescing and downtime significantly.
- BenjiWiebe 3y ago
  Sources? Has this worked for you? Maybe this is something I'll try.
  - 3seashells 3y ago
    https://en.m.wikipedia.org/wiki/Pyrotherapy https://en.m.wikipedia.org/wiki/Pyrotherapy
    - urbandw311er 3y ago
      “Later analyses have shown this might not have been true”
curiousObject 3y ago
>A tiny enough dose may even serve to remind our immune system of a pathogen’s existence, boosting our antibody response to keep us protected against it. This article should be required reading, whatever your views on Covid and other conditions. Although the attack method of the infection is significant, and the potential victim’s defenses are significant, the raw quantity of infectious agent and the exposure rate are also both important Nothing is certain. Everything is statistics.
- Sakos 3y ago
  This is one of the reasons why masks are so important and why they don't need to be 100% effective. Just reducing the amount of viral load could turn a serious infection into something you might barely notice. edit: Imagine this being controversial. I didn't realize there were Covid deniers and skeptics here, because what I've stated is completely within established science.
  - deleted 3y ago
    [deleted]
  - elsonrodriguez 3y ago
    The exploration of truth is anathema to those who claim to already have the truth.
  - pton_xd 3y ago
    > This is one of the reasons why masks are so important and why they don't need to be 100% effective. Just reducing the amount of viral load could turn a serious infection into something you might barely notice. It would be nice to have some numbers to back this up. Let's suppose the "viral load" to acquire a Covid infection is 18 particles, the same as norovirus detailed in the article. And let's say you're exposed to hundreds of thousands of viral particles every minute you spend near a sick person [1]. If a mask reduces your viral load by 50%, is that a worthwhile method of avoiding infection? [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7598485/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7598485/
    - sfblah 3y ago
      There are good studies on viral load reduction from masking with flu viruses from before 2020. After 2020 the topic became politicized so the studies are probably unreliable.
    - MrLeap 3y ago
      The assertion is that if you dump a gooey grey gallon of pure covid on someone, their symptoms will be more severe than if they only get 18 virions. Do you suppose that wouldn't be the case?
deleted 3y ago
[deleted]
swayvil 3y ago
There is also bodily vigor to consider. When you are strong you are resistant. When you are weak you are susceptible. The difference can be huge. It's a good argument for clean living, regular exercise etc.
- roywashere 3y ago
  When I was sixteen I sailed a lot on the lakes in my neighborhood. I was strong and healthy and thought: what could microbes do against 1 meter 90 of me? So I drank the water from the lake to see what would happen. I became rather sick to my stomach :-) and I considered defeat
  - yjftsjthsd-h 3y ago
    The claim was increased resilience, not perfect immunity.
  - smegsicle 3y ago
    about how much lakewater are we talking
- angst_ridden 3y ago
  Being in excellent health can increase the required pathogen dose, and help resist illness. It can also, paradoxically, cause worse results. See, for example, “cytokine storm.”
- user_7832 3y ago
  Why is this downvoted? Hygiene and exercise is sound advice that any doctor'd agree with.
  - extrememacaroni 3y ago
    Probably because the poor guy's theory isn't true for all possible cases ever, isn't peer reviewed etc.
  - dbsights 3y ago
sulam 3y ago
Just keep in mind, dose-dependence is variable. It’s not a virus, but even one cryptosporidium oocyst is enough to get you sick.
thenerdhead 3y ago
> Exposure is a function of pathogen concentration and contact time, so if you can reduce either of those, you can better avoid infectious diseases. What these articles don't talk about are the real-life challenges of concentration and contact time. For example, being a parent with a kid in school they might randomly sneeze or cough in my face while being completely asymptomatic. Then of course we all come down with covid later on. Secondly, the claims about viral load and shedding have conflicting science on new variants too: > https://www.nature.com/articles/s41591-022-01816-0#Sec7 https://www.nature.com/articles/s41591-022-01816-0#Sec7 i.e > Nevertheless, in our study, correlation between RNA and infectious VL was equally low between fully vaccinated and unvaccinated Delta-infected patients, indicating that factors other than mucosal neutralizing antibodies may be important for the reduction in infectious VL > Within 5 DPOS, we found higher RNA VLs but lower infectious VLs in swabs of unvaccinated patients with pre-VOC infections compared to Delta. These results disagree with other studies that analyzed only nucleic acid detection and found 3–10-fold-higher RNA copy number in Delta-infected patients compared to pre-VOC-infected patients > Although VL is a key element of transmission, the process of human-to-human transmission is complex, and other factors, such as varying recommended protection measures, overall incidence, perceived risks and the context of contacts (household versus community transmission), can influence outcomes in the studies reported. The best point from this article is the following: > Transmission dynamics are complex, but the interventions we can take to protect ourselves are comparatively simple.
uuuuuuuiiiiii 3y ago
[dead]
uuuuuuuiiiiii 3y ago
[dead]
gregwebs 3y ago
Great to see statistical thinking. There have been a lot of Covid shouting matches because people are trying to reduce things to binary. Masks don’t work! Actually, they work as advertised- only 95% effective at best (and a cloth mask may be 30%), not a binary protected or not. That’s effective at blocking particles. You are still guaranteed to get some virus particles. They are going to be in your respiratory tract trying to replicate, and maybe some are replicating-does that mean you are infected in a clinically meaningful way? Depends. Researchers will try to measure if some intervention like that works reporting binary PCR positive or negative- but we should want to know what was the severity of the illness. PCR positive with minor illness can be a good outcome indicating that the intervention helped lower the innoculum.
- PaulKeeble 3y ago
  Actually N95 is AT LEAST 95% effective. 95% is its worst case performance on a PM2.5 sized particle, at all other particle sizes it is better than 95% usually considerably. We also have N99 masks and even P100 respirators which do an even better job. We just need to start using them. We also need to educate ourselves how to fit and fit test a mask because if its leaking its not giving you that level of protection.
  - hamburglar 3y ago
    Well, the actual mask's performance is 95% effective, but you can't really make a guarantee about the overall worst case effectiveness when deployed by humans. N95 masks are not 95% effective on someone who has a big fluffy beard preventing a proper seal, for example. Or with people who use their gut feeling to decide where and when to put them on (like deciding if there's nobody in the elevator, you don't need it, ignoring the fact that someone may have gotten out of the elevator 20 seconds ago and left particulates in the air).
  - weaksauce 3y ago
    you're absolutely correct and furthermore smaller particles and larger particles are easier for the masks to catch to state it differently if it wasn't clear.
PaulKeeble 3y ago
Last paragraphs are really important recommendations for how to end the pandemic. "Masking, increased ventilation and distancing reduces the number of microbes you’re exposed to. Vaccination increases the infectious dose. " We really need to move beyond vaccine only, its not working Covid is just too transmissible.
- amanaplanacanal 3y ago
  Ventilation changes seem like a big deal. Unfortunately that requires businesses and government to spend money, instead of putting the burden on individuals. This would require regulatory action, and at least in the US we have important culture wars to fight instead.
zby 3y ago
If 400 microbes that contact your body makes you sick - then what if one virus gets into a cell and produces 400 copies? It is certainly possible: "For example, SIV, a cousin and model for the HIV virus, is released from infected T cells with a burst size of ≈50,000 (BNID 102377) whereas cyanobacterial viruses have characteristic burst sizes of ≈40-80" http://book.bionumbers.org/how-many-virions-result-from-a-single-viral-infection/ http://book.bionumbers.org/how-many-virions-result-from-a-si... So if not just one - then a few initial virions should be able to produce the infectious dose. I guess time is important here - the organism detects the initial virions and prepares defences - so if the infectious dose amount of virions comes after the organism is warned they fail to grow into an infection. But my intuition is that the complexity of that process and path dependence makes that infectious dose so variable - that it does not seem to be any useful.
- XorNot 3y ago
  No this is all statistics again: probability that a viral particles survives in the body, probability that it successfully enters the cell (this is all chemical kinetics so it's not 100%), probability the cell survives long enough to replicate the virus, probability of an immune response picking up the lyzed cell immediately and then repeat for the daughter copies. An analogous process would be human fertilization: it technically only takes 1 sperm to fertilize an egg, but it's millions in order to make the probability of it happening meaningfully high enough. Of course some viruses are stupidly good at this: it's estimated 5 norovirus particles will trigger a full blown infection.
HocusLocus 3y ago
Just one if it's a big one

145 points by meany 3y ago

A fascinating thing is that you can catch a infection early. If you know you have been exposed and time it right you can induce a artificial fever via sauna or steam bath. This catches the whole infection ahead of the curve and shortens reconvalescing and downtime significantly.

BenjiWiebe 3y ago
Sources? Has this worked for you? Maybe this is something I'll try.
- 3seashells 3y ago
  https://en.m.wikipedia.org/wiki/Pyrotherapy https://en.m.wikipedia.org/wiki/Pyrotherapy
  - urbandw311er 3y ago
    “Later analyses have shown this might not have been true”

curiousObject 3y ago

>A tiny enough dose may even serve to remind our immune system of a pathogen’s existence, boosting our antibody response to keep us protected against it. This article should be required reading, whatever your views on Covid and other conditions. Although the attack method of the infection is significant, and the potential victim’s defenses are significant, the raw quantity of infectious agent and the exposure rate are also both important Nothing is certain. Everything is statistics.

Sakos 3y ago
This is one of the reasons why masks are so important and why they don't need to be 100% effective. Just reducing the amount of viral load could turn a serious infection into something you might barely notice. edit: Imagine this being controversial. I didn't realize there were Covid deniers and skeptics here, because what I've stated is completely within established science.
- deleted 3y ago
  [deleted]
- elsonrodriguez 3y ago
  The exploration of truth is anathema to those who claim to already have the truth.
- pton_xd 3y ago
  > This is one of the reasons why masks are so important and why they don't need to be 100% effective. Just reducing the amount of viral load could turn a serious infection into something you might barely notice. It would be nice to have some numbers to back this up. Let's suppose the "viral load" to acquire a Covid infection is 18 particles, the same as norovirus detailed in the article. And let's say you're exposed to hundreds of thousands of viral particles every minute you spend near a sick person [1]. If a mask reduces your viral load by 50%, is that a worthwhile method of avoiding infection? [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7598485/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7598485/
  - sfblah 3y ago
    There are good studies on viral load reduction from masking with flu viruses from before 2020. After 2020 the topic became politicized so the studies are probably unreliable.
  - MrLeap 3y ago
    The assertion is that if you dump a gooey grey gallon of pure covid on someone, their symptoms will be more severe than if they only get 18 virions. Do you suppose that wouldn't be the case?

deleted 3y ago

[deleted]

swayvil 3y ago

There is also bodily vigor to consider. When you are strong you are resistant. When you are weak you are susceptible. The difference can be huge. It's a good argument for clean living, regular exercise etc.

roywashere 3y ago
When I was sixteen I sailed a lot on the lakes in my neighborhood. I was strong and healthy and thought: what could microbes do against 1 meter 90 of me? So I drank the water from the lake to see what would happen. I became rather sick to my stomach :-) and I considered defeat
- yjftsjthsd-h 3y ago
  The claim was increased resilience, not perfect immunity.
- smegsicle 3y ago
  about how much lakewater are we talking
angst_ridden 3y ago
Being in excellent health can increase the required pathogen dose, and help resist illness. It can also, paradoxically, cause worse results. See, for example, “cytokine storm.”
user_7832 3y ago
Why is this downvoted? Hygiene and exercise is sound advice that any doctor'd agree with.
- extrememacaroni 3y ago
  Probably because the poor guy's theory isn't true for all possible cases ever, isn't peer reviewed etc.
- dbsights 3y ago

sulam 3y ago

Just keep in mind, dose-dependence is variable. It’s not a virus, but even one cryptosporidium oocyst is enough to get you sick.

thenerdhead 3y ago

> Exposure is a function of pathogen concentration and contact time, so if you can reduce either of those, you can better avoid infectious diseases. What these articles don't talk about are the real-life challenges of concentration and contact time. For example, being a parent with a kid in school they might randomly sneeze or cough in my face while being completely asymptomatic. Then of course we all come down with covid later on. Secondly, the claims about viral load and shedding have conflicting science on new variants too: > https://www.nature.com/articles/s41591-022-01816-0#Sec7 https://www.nature.com/articles/s41591-022-01816-0#Sec7 i.e > Nevertheless, in our study, correlation between RNA and infectious VL was equally low between fully vaccinated and unvaccinated Delta-infected patients, indicating that factors other than mucosal neutralizing antibodies may be important for the reduction in infectious VL > Within 5 DPOS, we found higher RNA VLs but lower infectious VLs in swabs of unvaccinated patients with pre-VOC infections compared to Delta. These results disagree with other studies that analyzed only nucleic acid detection and found 3–10-fold-higher RNA copy number in Delta-infected patients compared to pre-VOC-infected patients > Although VL is a key element of transmission, the process of human-to-human transmission is complex, and other factors, such as varying recommended protection measures, overall incidence, perceived risks and the context of contacts (household versus community transmission), can influence outcomes in the studies reported. The best point from this article is the following: > Transmission dynamics are complex, but the interventions we can take to protect ourselves are comparatively simple.

uuuuuuuiiiiii 3y ago

[dead]

uuuuuuuiiiiii 3y ago

[dead]

gregwebs 3y ago

Great to see statistical thinking. There have been a lot of Covid shouting matches because people are trying to reduce things to binary. Masks don’t work! Actually, they work as advertised- only 95% effective at best (and a cloth mask may be 30%), not a binary protected or not. That’s effective at blocking particles. You are still guaranteed to get some virus particles. They are going to be in your respiratory tract trying to replicate, and maybe some are replicating-does that mean you are infected in a clinically meaningful way? Depends. Researchers will try to measure if some intervention like that works reporting binary PCR positive or negative- but we should want to know what was the severity of the illness. PCR positive with minor illness can be a good outcome indicating that the intervention helped lower the innoculum.

PaulKeeble 3y ago
Actually N95 is AT LEAST 95% effective. 95% is its worst case performance on a PM2.5 sized particle, at all other particle sizes it is better than 95% usually considerably. We also have N99 masks and even P100 respirators which do an even better job. We just need to start using them. We also need to educate ourselves how to fit and fit test a mask because if its leaking its not giving you that level of protection.
- hamburglar 3y ago
  Well, the actual mask's performance is 95% effective, but you can't really make a guarantee about the overall worst case effectiveness when deployed by humans. N95 masks are not 95% effective on someone who has a big fluffy beard preventing a proper seal, for example. Or with people who use their gut feeling to decide where and when to put them on (like deciding if there's nobody in the elevator, you don't need it, ignoring the fact that someone may have gotten out of the elevator 20 seconds ago and left particulates in the air).
- weaksauce 3y ago
  you're absolutely correct and furthermore smaller particles and larger particles are easier for the masks to catch to state it differently if it wasn't clear.

PaulKeeble 3y ago

Last paragraphs are really important recommendations for how to end the pandemic. "Masking, increased ventilation and distancing reduces the number of microbes you’re exposed to. Vaccination increases the infectious dose. " We really need to move beyond vaccine only, its not working Covid is just too transmissible.

amanaplanacanal 3y ago
Ventilation changes seem like a big deal. Unfortunately that requires businesses and government to spend money, instead of putting the burden on individuals. This would require regulatory action, and at least in the US we have important culture wars to fight instead.

zby 3y ago

If 400 microbes that contact your body makes you sick - then what if one virus gets into a cell and produces 400 copies? It is certainly possible: "For example, SIV, a cousin and model for the HIV virus, is released from infected T cells with a burst size of ≈50,000 (BNID 102377) whereas cyanobacterial viruses have characteristic burst sizes of ≈40-80" http://book.bionumbers.org/how-many-virions-result-from-a-single-viral-infection/ http://book.bionumbers.org/how-many-virions-result-from-a-si... So if not just one - then a few initial virions should be able to produce the infectious dose. I guess time is important here - the organism detects the initial virions and prepares defences - so if the infectious dose amount of virions comes after the organism is warned they fail to grow into an infection. But my intuition is that the complexity of that process and path dependence makes that infectious dose so variable - that it does not seem to be any useful.

XorNot 3y ago
No this is all statistics again: probability that a viral particles survives in the body, probability that it successfully enters the cell (this is all chemical kinetics so it's not 100%), probability the cell survives long enough to replicate the virus, probability of an immune response picking up the lyzed cell immediately and then repeat for the daughter copies. An analogous process would be human fertilization: it technically only takes 1 sperm to fertilize an egg, but it's millions in order to make the probability of it happening meaningfully high enough. Of course some viruses are stupidly good at this: it's estimated 5 norovirus particles will trigger a full blown infection.

HocusLocus 3y ago

Just one if it's a big one