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

Re:Surgical masks reduce Covid-19 spread, large-scale Stanfo... by jacquesm on Friday September 03, 2021 @03:18PM (#28408206)

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 like that'.

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Re:Surgical masks reduce Covid-19 spread, large-scale Stanfo... by nradov on Friday September 03, 2021 @04:16PM (#28408866)

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.

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Re:Surgical masks reduce Covid-19 spread, large-scale Stanfo... by jacquesm on Friday September 03, 2021 @04:23PM (#28408942)

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.

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Re:Surgical masks reduce Covid-19 spread, large-scale Stanfo... by nradov on Friday September 03, 2021 @04:28PM (#28408988)

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.

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Re:Surgical masks reduce Covid-19 spread, large-scale Stanfo... by polote on Friday September 03, 2021 @04:06PM (#28408762)

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

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Re:Surgical masks reduce Covid-19 spread, large-scale Stanfo... by jacquesm on Friday September 03, 2021 @04:16PM (#28408865)

> 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.

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