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Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

med.stanford.edu

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Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#181

Post by phreeza »

belorn wrote: post #124

Its interesting that the article do not mention a rather interesting finding in the study. For the age groups of Why aren't masks effective to reduce the spread for that age group? The discussion part of the study don't explore it. Is the distancing behavior of people aged 50 or higher different than those below? I would like to see further studies being done on the younger demographic in order to explain why the dat…

I think the limited specificity of their definition of COVID-19 means it is easier to detect effects for populations that have higher incidence.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#182

Post by polote »

daveguy wrote: post #148
polote wrote: post #127

Earlier quoted context omitted.

At the end of the day if the reduction is 11%, even if that works (because that reduce by 11%) that is still useless in order to control the epidemic. Unless we find 10 measures like that. But what they show is probably not the same that the impact of mask mandate or an `always wear mask` at the personal level. So not much is applicable about that study. Only that mask kind of reduce covid spread

It doesn't take 100% control to make a significant impact. Every % you take off of transmission is significant because the relationship between transmission and cases is exponential.

100% is impossible and was not the point I was making. The only things that is import is R is below or equal 1.

The relation between transmission and cases is not exponential as :

1. Cases can't go to infinity

2. R is variable, and actually changes a lot for plenty of reasons

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#183

Post by jacquesm »

polote wrote: post #180
jacquesm wrote: post #147

Earlier quoted context omitted.

You are making a number of pretty common errors: no anti-viral measure is going to be perfect, it is always going to be a layercake and an 11% improvement can make a huge difference because for one it might tip the balance from 1.05 to 0.95 which is the difference between a spreading disease and one that is on the return and because these percentages are multiplicative, not additive, so it would not take '10 measures…

I didn't come up to the number 10 because 10 * 11% is about 100%. its just a random guess about small impact measure We know that R of covid in a naive environment is probably more than 4. So any group of measure that dont reduce it 1 is not going to be enough. There is no 1.05 in reality for covid. When you are at 1.05 it is already because of group of measures are in place

> When you are at 1.05 it is already because of group of measures are in place

Ah and here I was thinking you thought those weren't effective. Ok, sorry.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#184

Post by nradov »

jacquesm wrote: post #147
polote wrote: post #127

Earlier quoted context omitted.

At the end of the day if the reduction is 11%, even if that works (because that reduce by 11%) that is still useless in order to control the epidemic. Unless we find 10 measures like that. But what they show is probably not the same that the impact of mask mandate or an `always wear mask` at the personal level. So not much is applicable about that study. Only that mask kind of reduce covid spread

You are making a number of pretty common errors: no anti-viral measure is going to be perfect, it is always going to be a layercake and an 11% improvement can make a huge difference because for one it might tip the balance from 1.05 to 0.95 which is the difference between a spreading disease and one that is on the return and because these percentages are multiplicative, not additive, so it would not take '10 measures…

The Delta variant R0 is in the 6-7 range.

https://www.npr.org/sections/goatsandsoda/2021/08/11/1026190...

There is no plausible way to bring it below 1 for an extended period of time. The most we can do is slow it down a little.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#185

Post by helge9210 »

WarOnPrivacy wrote: post #168
helge9210 wrote: post #157

Earlier quoted context omitted.

I totally agree. On the other hand I would like to opt out of this exercise, since I'm totally not concerned with COVID.

I know a place where workers keep having to quarantine following covid reoccurrences. Looking for a job?

Stop testing and there won't be new cases.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#186

Post by fulafel »

Is to possible to measure or control for behavioral, vs direct transmission blocking, effects of masks? If they seem more effective for old people, could it be that they help remind people about the ongoing pandemic and infection risk, and signal that mask wearers prefer to keep distance to others.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#187

Post by jacquesm »

nradov wrote: post #184
jacquesm wrote: post #147

Earlier quoted context omitted.

You are making a number of pretty common errors: no anti-viral measure is going to be perfect, it is always going to be a layercake and an 11% improvement can make a huge difference because for one it might tip the balance from 1.05 to 0.95 which is the difference between a spreading disease and one that is on the return and because these percentages are multiplicative, not additive, so it would not take '10 measures…

The Delta variant R0 is in the 6-7 range. https://www.npr.org/sections/goatsandsoda/2021/08/11/1026190... There is no plausible way to bring it below 1 for an extended period of time. The most we can do is slow it down a little.

You are mistaken about what R0 means. It is a compound number that describes a virus and its ability to spread from person to person in a community, with all the measures (or lack thereof) including vaccinations in place.

The 6-7 range would be in a theoretical environment where nobody is vaccinated, there are absolutely no countermeasures and the number of opportunities to spread is equivalent to the pre-COVID days. Obviously, we do not live in that world.

In short, R0 is not a property of a particular virus strain but of the sum total of virus + all factors relating to population, behavior etc.

It is also best determined afterwards the way it is being treated right now as though it is some kind of input variable which can be controlled for is fundamentally wrong.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#188

Post by nradov »

jacquesm wrote: post #187
nradov wrote: post #184

Earlier quoted context omitted.

The Delta variant R0 is in the 6-7 range. https://www.npr.org/sections/goatsandsoda/2021/08/11/1026190... There is no plausible way to bring it below 1 for an extended period of time. The most we can do is slow it down a little.

You are mistaken about what R0 means. It is a compound number that describes a virus and its ability to spread from person to person in a community, with all the measures (or lack thereof) including vaccinations in place. The 6-7 range would be in a theoretical environment where nobody is vaccinated, there are absolutely no countermeasures and the number of opportunities to spread is equivalent to the pre-COVID days.…

I understand what R0 means perfectly well. Vaccination and other factors can reduce it from the 6-7 level to something a bit lower. But there is no plausible sum of factors that will bring it below 1 for an extended period any time soon. Most interventions are correlated, not independent, and so the sum is less than the parts.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#189

Post by WarOnPrivacy »

helge9210 wrote: post #185
WarOnPrivacy wrote: post #168

Earlier quoted context omitted.

I know a place where workers keep having to quarantine following covid reoccurrences. Looking for a job?

Stop testing and there won't be new cases.

Because dead people don't replicate viruses well. Got it.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#190

Post by helge9210 »

WarOnPrivacy wrote: post #189
helge9210 wrote: post #185

Earlier quoted context omitted.

Stop testing and there won't be new cases.

Because dead people don't replicate viruses well. Got it.

Only 0.6% will die (on average over all age groups). 99.4% will have an immunity for half a year.
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