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How many microbes does it take to make you sick?

quantamagazine.org

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Re: How many microbes does it take to make you sick?

#11

Post by jameshart »

dorfsmay wrote: post #8
curiousObject wrote: post #2

> 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 a…

> boosting ourantibody response What I wonder is if we can develop immunity (not boosting, assuming never been infected before) from being exposed to small doses, or do we need at least one full blown infection.

Not sure why you are suggesting the basic mechanism of inoculation, which has been known for centuries and is the fundamental mechanism behind vaccination, as if it’s a novel hypothesis. Have I misunderstood what you’re getting at?

Re: How many microbes does it take to make you sick?

#12

Post by pton_xd »

Sakos wrote: post #5
curiousObject wrote: post #2

> 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 a…

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.

> 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/

Re: How many microbes does it take to make you sick?

#14

Post by vikramkr »

dorfsmay wrote: post #8
curiousObject wrote: post #2

> 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 a…

> boosting ourantibody response What I wonder is if we can develop immunity (not boosting, assuming never been infected before) from being exposed to small doses, or do we need at least one full blown infection.

Yep that's called vaccination! No need to get a full blown infection it's how we eradicated smallpox

Re: How many microbes does it take to make you sick?

#15

Post by thenerdhead »

> 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

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.

Re: How many microbes does it take to make you sick?

#16

Post by sfblah »

Sakos wrote: post #5
curiousObject wrote: post #2

> 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 a…

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.

What you said isn’t controversial. It’s definitely right.

The issue with masks is one side started treating them like a talisman that makes infection impossible, which provoked the other side to say they do nothing.

On a population level, masks are probably close to ineffective against a viral pathogen. You can read the relevant Cochrane review to see that.

On an individual level they obviously do something, but you have to consider other factors as well, such as level/frequency of exposure and the like. Studies from prior to the pandemic suggested that a perfectly fitted N95 mask dramatically reduced flu virus penetration. For a more normally worn N95 the reduction was about 70%. For a surgical mask it was essentially nil. Importantly, a perfectly fitted mask required essentially gluing it to the face of a mannequin.

Final point is, with an intervention whose impact is measurable but imperfect, you have to consider the side effects. I personally know several friends of my teenage kids who now have odd (to me at least) social phobias for which the only “cure” is to wear masks everywhere. Just last weekend I was talking to a friend of my daughter who wears masks everywhere except indoors.

Re: How many microbes does it take to make you sick?

#17

Post by user_7832 »

swayvil wrote: post #4

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.

Why is this downvoted? Hygiene and exercise is sound advice that any doctor'd agree with.

Re: How many microbes does it take to make you sick?

#18

Post by sfblah »

pton_xd wrote: post #12
Sakos wrote: post #5

Earlier quoted context omitted.

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.

> 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…

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.

Re: How many microbes does it take to make you sick?

#19

Post by User23 »

Sakos wrote: post #5
curiousObject wrote: post #2

> 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 a…

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.

RCTs show surgical and cloth masks to be ineffective or nearly so for reducing the spread of respiratory viruses. Obviously the kinds of masks used in BSL labs do work to prevent spread.

However there are statistics that areas with more masking had less severe illness. However that’s uncontrolled and some other factors or factors might account for both increased masking and reduced spread. That’s probably the case otherwise the RCTs would show efficacy.

All of the subsequent work is just computer models and doesn’t actually tell us anything empirical. Obviously it’s easier to create a model that produces the desired result than it is an RCT.

Re: How many microbes does it take to make you sick?

#20

Post by MrLeap »

pton_xd wrote: post #12
Sakos wrote: post #5

Earlier quoted context omitted.

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.

> 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…

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?
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