Face masks effectively limit the probability of SARS-CoV-2 transmission • Hacker News Board

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#381

Post by simpleguitar » Sat, May 22, 2021, 4:05 PM UTC

nimish wrote: post #274

simpleguitar wrote: post #243

Earlier quoted context omitted.

One problem--ethics. Can't knowingly give humans less protection. It's not a money problem.

That is what you are testing! Equipoise demands you don't assume one outcome. Otherwise every single pharmaceutical trial would be impossible since "we can't knowingly give humans a placebo" If the effect is large and significant we will see it quickly and can halt asap.

"29. The benefits, risks, burdens and effectiveness of a new method should be tested against those of the best current prophylactic, diagnostic, and therapeutic methods. This does not exclude the use of placebo, or no treatment, in studies where no proven prophylactic, diagnostic or therapeutic method exists."

https://en.wikipedia.org/wiki/Placebo-controlled_study#Decla...

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#382

Post by dragonwriter » Sat, May 22, 2021, 5:42 PM UTC

asabjorn wrote: post #376

dragonwriter wrote: post #373

Earlier quoted context omitted.

> As some signal for this Florida is USAs old people home, so you would expect that if masks had a large positive mitigatory effect then Florida with its low mask use would do worse than CA and NY that has low mask use. Again, this has a problem of failing to address case timing and distribution, with CA and NY being hard hit and having COVID into the community before there was much awareness or any policy response (…

I tend to trust state policy and political leanings more as an indicator then a self reported study. Can you please dig into why you trust this self reported study on the politically charged mask use question? Especially when the study is performed by academics that is perceived to be too often left-wing activists by republicans and many libertarians? (And according to Haidt have a provably largely left leaning bias)…

> I tend to trust state policy and political leanings more as an indicator then a self reported study.

I don’t, in the absence of strong enforcement of policy (which did not exist in, e g., California COVID policy), especially on issues of strong partisan posturing; even solid red or blue states tend to be pretty closely balanced in the population; majoritarianism, reinforced by gerrymandering and related mechanisms, produces strong and durable political dominance from slight population imbalances, so “state dominant party” stereotypes and state policy vastly exaggerate differences in distribution of individual belief, preference, and, in the absence of effective compulsion, behavior.

> To indicate the problem you can observed how inaccurate polls around politically charged choices has become when compared to actual choices.

They...haven’t, really, become particularly inaccurate. Poll-based predictions of binary outcomes of things that poll very close to even have become somewhat less reliable than they very briefly were before (they were a fairly new practice compared to just reporting polls without predictions, anyway, so its not like there was a well-established baseline) because when polls are near even, very slight changes in accuracy have an outsize effect on binary predictions.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#383

Post by epivosism » Sat, May 22, 2021, 6:27 PM UTC

ppf wrote: post #264

epivosism wrote: post #59

Earlier quoted context omitted.

Yes. Crazy how hard it has been for people to get this: Imagine a bulletproof vest with three larger-than-bullet-sized holes in it. Say you know someone is going to shoot ten bullets at you - would you not wear the vest because "the attack vector can fit through the pores"? The point is people treat this as a binary 'safe' / 'not safe' switch, when actually risk is related to the distribution of exposure to dosage.

If we're talking about the size of the holes in a mask compared to a virus, then it would be more like wearing a "bulletproof" vest full of holes 10x bigger than a bullet.

I guess it's a choice of analogy. If virus particles are like bullets, protection can be viewed as proportional. But if it's viewed more like a liquid, seeping through any hole, then only full watertight protection works. I'd argue that the reduced transmissibility we see from outdoor exposure supports the first of those as a more apt analogy.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#384

Post by jonplackett » Sat, May 22, 2021, 7:17 PM UTC

mike_hearn wrote: post #379

jonplackett wrote: post #378

Earlier quoted context omitted.

Ok, makes sense. But why does this make any difference to the crux of my argument? - if that supermarket employee is wearing a mask, they’re going to spread it to less people.

R=1.1=everything goes to shit is not a valid inference. R is just the derivative of the case graph. It can and does change on a daily basis, says nothing about absolute levels, and says nothing about how it will evolve over time or what the actual peak levels of infections will be. You can find "exponential growth" in nearly any graph if you want, look at a sine wave for example, and viruses in particular are a curio…

Ok so what I mean is r being 1.1... over time.

I think you’re looking to find holes in a perfectly reasonable argument by adding complexity.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#385

Post by chrismcb » Sun, May 23, 2021, 4:56 AM UTC

boplicity wrote: post #338

andreygrehov wrote: post #210

Earlier quoted context omitted.

It's not a myth. I'm looking at statistics right now. A myth is that Florida has fared very badly (most likely a politically inspired myth). Compared to other states, it hasn't. It's indeed in the middle, meaning that Florida does better than half the states of the USA. It's on par with California numbers, but I've never heard anyone (in the media) slamming very badly on Cali. I honestly don't believe that a mask can…

I think you missed my point that the United States has fared very badly and that Florida sits right in the middle of the pack, in the States. California has fared very badly as well, but that's a separate point. I think many Americans are so insular, they forget there's more to the world than just the States.

US hasn't fared that badly, they are in the middle, as far as per population goes. But that isn't really the point, it maybe it is. The point is that comparing California and Florida, they did roughly the same, despite attacking the issue differently. This isn't to say how well Florida or California did compared to the rest of the world.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#386

Post by mhb » Sun, May 23, 2021, 1:08 PM UTC

admax88q wrote: post #357

mhb wrote: post #330

Earlier quoted context omitted.

Grant me the steel man. What's the mental model of the people wearing them outside on a walk in the woods or on a beach? Not the inconvenience of taking them off between stops at the bank and the drug store.

I don't know, but who cares. Maybe for pollen and dust allergies. Part of the problem is everyone feels the need to judge others. Why does it bother you that people wear masks on the beach? Why can't you just let them be?

I don't care what the others are doing per se. In fact, I think it's optimal if everyone else would wear a mask all the time.

What bothers me is that the sort of inconsistency I described is emblematic of the same muddled thinking that the CDC has demonstrated throughout. This is a problem for a number of reasons.

When people don't understand the reasoning behind a policy they are less likely to comply with it and it will lead to excess deaths.

Another reason is that, if no explanation or an incoherent explanation is given for a recommendation, people have to decide whether to follow it based solely on trust or the authority of the recommender. I don't think either of these is good for the long term health of society. You can see how this problem has manifested itself in the resistance of many people to being vaccinated or wearing masks.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#387

Post by mike_hearn » Sun, May 23, 2021, 1:36 PM UTC

jonplackett wrote: post #384

mike_hearn wrote: post #379

Earlier quoted context omitted.

R=1.1=everything goes to shit is not a valid inference. R is just the derivative of the case graph. It can and does change on a daily basis, says nothing about absolute levels, and says nothing about how it will evolve over time or what the actual peak levels of infections will be. You can find "exponential growth" in nearly any graph if you want, look at a sine wave for example, and viruses in particular are a curio…

Ok so what I mean is r being 1.1... over time. I think you’re looking to find holes in a perfectly reasonable argument by adding complexity.

Over how much time and how does that variable relate to the actual length of time an epidemic of an (apparently) seasonal respiratory virus is expected to last?

I don't think it's just a nitpicky minor thing. Governments have pretty regularly been making decisions and citing the value of "R" (they mean Rt), or "exponential growth", as a justification for new restrictions, apparently without realizing that by itself these things means little and justify nothing. Exponential growth can only be said to be a problem when taking into account the serial interval, the actual exponent, the starting population sizes, total population sizes, fixed capacity limits (e.g. hospital bed counts) and so on. Yet the scientists advising governments routinely ignore all those things.