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Yeah, it really doesn't seem all that plausible that cloth masks do much at this point. Not only was there never good evidence for them working, the best ones o

by makomk 5y ago

Yeah, it really doesn't seem all that plausible that cloth masks do much at this point. Not only was there never good evidence for them working, the best ones only block something like 90% of virus-bearing particles. To put this in context current estimates seem to be that people infected with Delta produce 100-1000x the amount of virus that previous variants did; the effect of mask wearing is absolutely miniscule compared to that.

ALittleLight 5y ago
How is blocking X% of the virus particles less impactful if there's more of them? Fewer particles admitted means reduced chance of infection, no? Always better to less virus particles than more.
- Veen 5y ago
  But almost no one is wearing the best sort of mask. They're wearing porous cloth masks that stop next to nothing.
  - kube-system 5y ago
    > next to nothing. Not true. https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/masking-science-sars-cov2.html https://www.cdc.gov/coronavirus/2019-ncov/science/science-br...
    - Veen 5y ago
      Are cloth masks any good? CDC says yes. BMJ says maybe, if you get the right masks. France says no and you should be wearing medical masks. DANMASK-19 says less than 50% effective and no significant difference in infections among populations who wear and don't wear masks. Who's a fellow to believe? - https://www.bmj.com/content/372/bmj.n432 https://www.bmj.com/content/372/bmj.n432
- chlodwig 5y ago
  Fewer particles admitted means reduced chance of infection, no? The thing to keep in mind is that blocking 50% of the particles does not mean a 50% reduction in infection. It may mean a 50% reduction in infection -- or it may mean a basically zero percent reduction. It depends on the exposure. Say that in a particular covid-filled room you have a 50% chance of being infected after 5 minutes and a 99.9% chance of being infected after an hour. Under a simple model, if you wear a mask that blocks half the particles, your chance of getting coronavirus in 5 minutes would be reduced to 25%, but your chance of getting it after an hour would be 97%. So if cloth mask is your primary defense against covid, you are eventually going to get covid if you are trying to live anything close to a normal life. Blocking 50% of particles is like wearing an condom that only blocks 50% of the sperm or an umbrella that blocks only 50% of the rain.
  - elmalto 5y ago
    I don’t think anyone is advocating for masks as your only line of defense, just one of a few (vaccines currently being the best)
  - kube-system 5y ago
    Pregnancy is boolean. A person's viral load is not a boolean value. The umbrella is a better comparison. My umbrella doesn't prevent 100% of the rain from coming in contact with me. This is good enough that the umbrella is still standard practice.
    - chlodwig 5y ago
      Are you referring to the theory that the severity of covid has a dose-response relationship with the infectious inoculum? It's an interesting theory, but I think it is far from proven. It's a shame that it's not studied, because if true it might actually make sense to just give everyone a very small infectious inoculum as a form of vaccination.
      - kube-system 5y ago
        The infectious dose of viruses is usually not (never?) a single particle. Depending on the virus, it may be tens or hundreds of particles required to infect a person. We don't know an exact number for COVID, but we know that it's likely some number that's greater than one. Whatever that number is, if we limit the number of particles in the air, we decrease the statistical probability that a person will come in contact to a number of particles exceeding that number. It's a "solution to pollution is dilution" issue. > it might actually make sense to just give everyone a very small infectious inoculum as a form of vaccination. The biggest issue with this, as I understand, is straddling the line between causing an immune response and hurting the patient. There are live vaccine viruses, but most (all?) attenuate the virus to prevent the latter.
andybak 5y ago
I don't follow this reasoning. An imperfect mask is surely going to result in a borderline contacts with infection being non-infections. The debate is "by how much" and without really clear evidence to the contrary, the precautionary principle wins. Wearing masks is usually only a minor inconvenience. I'm gobsmacked how it's become such a battleground.
- leereeves 5y ago
  > An imperfect mask is surely going to result in a borderline contacts with infection being non-infections. Not necessarily. The mask blocks the virus going both ways, so maybe only 10% of the virus particles get inside the mask, but 90% of those that would be exhaled also stay inside the mask. This is not an opinion on whether masks work, just an illustration that it's plausible they don't.
  - elmalto 5y ago
    Napkin math would be: 90% of infected person virus stays in 90% of virus does not get in for a healthy person So 1% (10% through * 10% through) of final particles will be inside the mask. Hence roughly 0.9% of particles (90% stays inside of the mask of the healthy person) would stick around by this logic Vs 100% of particles that could enter will enter without any sort of mask
    - leereeves 5y ago
      Even for napkin math we'd need reasonably good approximations, but we're missing a crucial number (how many virus particles are normally exhaled?) and I don't know if 90% blockage is accurate either (I'm just using it as an example because other posts in this thread have used that number).
      - andybak 5y ago
        > but we're missing a crucial number Exactly. We're lacking a crucial number. So wear a mask.
kiba 5y ago
That's why we social distance and use other methods. It's defense in depth. Though it seemed that these days we mostly stopped social distancing.
- nradov 5y ago
  You obviously can't expect people to continue social distancing. It's not sustainable, and harms mental health.
  - Bud 5y ago
    Killing your friends and family harms mental health a lot more.
hackinthebochs 5y ago
Viral load during initial infection is also implicated in severity of illness. Blocking 90% of particles can be the difference between life and death for some people.

by makomk 5y ago

ALittleLight 5y ago

How is blocking X% of the virus particles less impactful if there's more of them? Fewer particles admitted means reduced chance of infection, no? Always better to less virus particles than more.

Veen 5y ago
But almost no one is wearing the best sort of mask. They're wearing porous cloth masks that stop next to nothing.
- kube-system 5y ago
  > next to nothing. Not true. https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/masking-science-sars-cov2.html https://www.cdc.gov/coronavirus/2019-ncov/science/science-br...
  - Veen 5y ago
    Are cloth masks any good? CDC says yes. BMJ says maybe, if you get the right masks. France says no and you should be wearing medical masks. DANMASK-19 says less than 50% effective and no significant difference in infections among populations who wear and don't wear masks. Who's a fellow to believe? - https://www.bmj.com/content/372/bmj.n432 https://www.bmj.com/content/372/bmj.n432
chlodwig 5y ago
Fewer particles admitted means reduced chance of infection, no? The thing to keep in mind is that blocking 50% of the particles does not mean a 50% reduction in infection. It may mean a 50% reduction in infection -- or it may mean a basically zero percent reduction. It depends on the exposure. Say that in a particular covid-filled room you have a 50% chance of being infected after 5 minutes and a 99.9% chance of being infected after an hour. Under a simple model, if you wear a mask that blocks half the particles, your chance of getting coronavirus in 5 minutes would be reduced to 25%, but your chance of getting it after an hour would be 97%. So if cloth mask is your primary defense against covid, you are eventually going to get covid if you are trying to live anything close to a normal life. Blocking 50% of particles is like wearing an condom that only blocks 50% of the sperm or an umbrella that blocks only 50% of the rain.
- elmalto 5y ago
  I don’t think anyone is advocating for masks as your only line of defense, just one of a few (vaccines currently being the best)
- kube-system 5y ago
  Pregnancy is boolean. A person's viral load is not a boolean value. The umbrella is a better comparison. My umbrella doesn't prevent 100% of the rain from coming in contact with me. This is good enough that the umbrella is still standard practice.
  - chlodwig 5y ago
    Are you referring to the theory that the severity of covid has a dose-response relationship with the infectious inoculum? It's an interesting theory, but I think it is far from proven. It's a shame that it's not studied, because if true it might actually make sense to just give everyone a very small infectious inoculum as a form of vaccination.
    - kube-system 5y ago
      The infectious dose of viruses is usually not (never?) a single particle. Depending on the virus, it may be tens or hundreds of particles required to infect a person. We don't know an exact number for COVID, but we know that it's likely some number that's greater than one. Whatever that number is, if we limit the number of particles in the air, we decrease the statistical probability that a person will come in contact to a number of particles exceeding that number. It's a "solution to pollution is dilution" issue. > it might actually make sense to just give everyone a very small infectious inoculum as a form of vaccination. The biggest issue with this, as I understand, is straddling the line between causing an immune response and hurting the patient. There are live vaccine viruses, but most (all?) attenuate the virus to prevent the latter.

andybak 5y ago

I don't follow this reasoning. An imperfect mask is surely going to result in a borderline contacts with infection being non-infections. The debate is "by how much" and without really clear evidence to the contrary, the precautionary principle wins. Wearing masks is usually only a minor inconvenience. I'm gobsmacked how it's become such a battleground.

leereeves 5y ago
> An imperfect mask is surely going to result in a borderline contacts with infection being non-infections. Not necessarily. The mask blocks the virus going both ways, so maybe only 10% of the virus particles get inside the mask, but 90% of those that would be exhaled also stay inside the mask. This is not an opinion on whether masks work, just an illustration that it's plausible they don't.
- elmalto 5y ago
  Napkin math would be: 90% of infected person virus stays in 90% of virus does not get in for a healthy person So 1% (10% through * 10% through) of final particles will be inside the mask. Hence roughly 0.9% of particles (90% stays inside of the mask of the healthy person) would stick around by this logic Vs 100% of particles that could enter will enter without any sort of mask
  - leereeves 5y ago
    Even for napkin math we'd need reasonably good approximations, but we're missing a crucial number (how many virus particles are normally exhaled?) and I don't know if 90% blockage is accurate either (I'm just using it as an example because other posts in this thread have used that number).
    - andybak 5y ago
      > but we're missing a crucial number Exactly. We're lacking a crucial number. So wear a mask.

kiba 5y ago

That's why we social distance and use other methods. It's defense in depth. Though it seemed that these days we mostly stopped social distancing.

nradov 5y ago
You obviously can't expect people to continue social distancing. It's not sustainable, and harms mental health.
- Bud 5y ago
  Killing your friends and family harms mental health a lot more.

hackinthebochs 5y ago

Viral load during initial infection is also implicated in severity of illness. Blocking 90% of particles can be the difference between life and death for some people.