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Updating Herd Immunity Models for the US: Implications for the Covid-19 Response

medrxiv.org

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Re: Updating Herd Immunity Models for the US: Implications for the Covid-19 Response

#121

Post by ignoramous »

jupp0r wrote: post #15

Keep in mind that "herd immunity" isn't really immunity, it's the point at which Rt (the average number of people each infected person passes the infection on to) drops below 1.0 and the spread shrinks instead of growing. Rt is dependent on how people behave. When behavior changes, Rt can change as well. Each herd immunity level is thus dependent on health measures, which is why "reaching" herd immunity and then loos…

> Each herd immunity level is thus dependent on health measures, which is why "reaching" herd immunity and then loosening up health measures won't work.

Yep. Here's a very approachable and well written paper on the topic: https://academic.oup.com/cid/article/52/7/911/299077

And my comment on it from 6 months ago: https://news.ycombinator.com/item?id=22818413

Re: Updating Herd Immunity Models for the US: Implications for the Covid-19 Response

#122

Post by maerF0x0 »

SpicyLemonZest wrote: post #8
blakesterz wrote: post #3

I really struggle reading academic studies still... "Heterogeneity in contact structure and individual variation in infectivity, susceptibility, and resistance are key factors that reduce the disease-induced herd immunity levels to 34.2-47.5% in our models." I THINK that means, in addition to how infectious COVID is, and how susceptible and resistant people are in general, one of the other things that impact herd imm…

Yeah, that's what it's referring to. People with more points of contact are both more likely to catch the virus and have a larger impact on herd immunity once they're immune.

An example of applying such a concept: vaccinating healthcare workers ahead of otherwise isolated people.

I presume many healthcare workers see orders of magnitude more people per day than average and those people are more likely to be sick (else why are they getting healthcare?) .

Re: Updating Herd Immunity Models for the US: Implications for the Covid-19 Response

#123

Post by mcguire »

hammock wrote: post #75
mcguire wrote: post #64

Earlier quoted context omitted.

Are you seriously suggesting we lock over 110,000,000 people (34% of the population) in close quarantine for the duration? How do you plan to feed them? Get them medical care (be sure you don't overwhelm the system with the under 50s that get sick)? Keep them from rioting against their captors? What happens when you decide it's good enough and release them, and the residual infection sweeps through that population li…

>Are you seriously suggesting we lock over 110,000,000 people (34% of the population) in close quarantine for the duration? As opposed to 100% of the population? It sounds like an improvement to me. I'm suggesting relaxing restrictions for a part of the population, not increasing them.

If you think 100% of the population of the United States is in quarantine now, I suggest you check the definition of quarantine.

If you relax "restrictions" on a part of the population, more of that population becomes infected. If you do not increase the restrictions on the remainder of the population, the higher prevalence increases the transmission rate in that remainder. And thus deaths.

I'm sorry if my existence is inconveniencing you.

Re: Updating Herd Immunity Models for the US: Implications for the Covid-19 Response

#124

Post by xadhominemx »

sfblah wrote: post #114
xadhominemx wrote: post #109

Earlier quoted context omitted.

Who is suggesting 100% of the population be under close quarantine? We haven’t seen anything like that since April.

Bay area resident here. My kids can't go to school. I barely go to the store. Even going for a walk is tricky, as unless you take massive precautions (which I'm fine with, btw) everyone yells at you. I basically have no human contact outside my family, and it's been like this for six months. So, yeah, for me the situation couldn't really get much more quarantined.

That doesn’t sound like close quarantine at all

Re: Updating Herd Immunity Models for the US: Implications for the Covid-19 Response

#125

Post by argonaut »

Animats wrote: post #84

Whatever happened to large-scale antibody testing? You'd think that someone would be testing a few thousand random people each week to see how many people have been infected to date. That sort of thing was being done in the US back in April.[1][2] But it seems to have stopped. If you're going to talk about "herd immunity", you need that info to get anywhere. [1] https://www.medrxiv.org/content/10.1101/2020.04.14.2006…

Unfortunately, even antibody testing is unreliable now because of waning antibodies.

(One might object and say that if someone has little to no levels of antibodies they must not be immune anymore, but immunity is complex and not solely determined by antibodies)

Re: Updating Herd Immunity Models for the US: Implications for the Covid-19 Response

#126

Post by bigbubba »

mikelward wrote: post #74
pbhjpbhj wrote: post #55

Earlier quoted context omitted.

FWIW they almost certainly didn't write on a cigarette package in this instance ;o) It's just the name of that type of maths because people used to use whatever small, available, piece of paper was around - so cigarette packs some time ago (you definitely could write on them with a ballpoint pen (ie un bic ). Getting tangential, napkins to me in the UK have always been cloth, and we have serviettes (a French word, me…

I can't decide whether to use the term cutlery (mainly UK) or silverware (mainly US). They're both inaccurate, especially when asking for plastic/disposable versions.

'Utensils' seems accurate, although imprecise.

Re: Updating Herd Immunity Models for the US: Implications for the Covid-19 Response

#127

Post by salmon30salmon »

xadhominemx wrote: post #111
timr wrote: post #35

Gabriela Gomes was one of the first epidemiologists making this observation (as far back as May), and has found even lower thresholds (10-20%): https://www.medrxiv.org/content/10.1101/2020.04.27.20081893v... https://www.medrxiv.org/content/10.1101/2020.07.23.20160762v... https://www.medrxiv.org/content/10.1101/2020.09.26.20202267v...

Well 20% of NYC had COVID and we are currently seeing outbreaks in communities that have relaxed social distancing measures, so it seems obvious that her calculations are incorrect.

That’s part of the thesis of the article. Some populations mix more than others. In the mixing populations the threshold will be higher. In populations with limited mixing, lower.

20% of NYC can have the virus and the general level for herd immunity can still be what is postulated. NYC is incredibly dense compared to the rest of the USA and as such will naturally have more mixing and a higher threshold than say Topeka, Kansas

Re: Updating Herd Immunity Models for the US: Implications for the Covid-19 Response

#128

Post by goalieca »

regularfry wrote: post #99
goalieca wrote: post #71

Earlier quoted context omitted.

This is roughly what is called for here by some of the leading experts: https://gbdeclaration.org/

These are not "some of the leading experts". https://www.wired.co.uk/article/great-barrington-declaration...

Wired? Seriously? I don’t even trust them for tech news.

Here are the authors. They are well credentialed

Dr. Martin Kulldorff, professor of medicine at Harvard University, a biostatistician, and epidemiologist with expertise in detecting and monitoring of infectious disease outbreaks and vaccine safety evaluations.

Dr. Sunetra Gupta, professor at Oxford University, an epidemiologist with expertise in immunology, vaccine development, and mathematical modeling of infectious diseases.

Dr. Jay Bhattacharya, professor at Stanford University Medical School, a physician, epidemiologist, health economist, and public health policy expert focusing on infectious diseases and vulnerable populations.

Re: Updating Herd Immunity Models for the US: Implications for the Covid-19 Response

#129

Post by JoshuaDavid »

oopsiforgot7 wrote: post #21
jupp0r wrote: post #15

Keep in mind that "herd immunity" isn't really immunity, it's the point at which Rt (the average number of people each infected person passes the infection on to) drops below 1.0 and the spread shrinks instead of growing. Rt is dependent on how people behave. When behavior changes, Rt can change as well. Each herd immunity level is thus dependent on health measures, which is why "reaching" herd immunity and then loos…

When non experts talk about herd immunity they mean herd immunity given no to minimal precautions. This is a well defined concept.

Yeah. The term "endemic steady state" would be more accurate, but "herd immunity" is the term everyone ended up using.

Re: Updating Herd Immunity Models for the US: Implications for the Covid-19 Response

#130

Post by emodendroket »

guscost wrote: post #117
meowzero wrote: post #101

Earlier quoted context omitted.

That is a good strategy. Unfortunately, ppl with survival rate above 99.99% might live with more vulnerable population. It'll be difficult to figure out how to effectively quarantine the more vulnerable population away from the less-vulnerable.

Why not allow healthy people to inoculate with a reasonable dose of the virus so they can control the timing, and then self-quarantine? I would have done that months ago if it was allowed. Even if it only has a partial chance of conferring immunity, doing that would have helped fewer vulnerable people get sick, but instead public health authorities are still clinging to “informed consent” nonsense, as if turning the…

Maybe I'm missing something but it seems like you're just independently inventing the concept of a vaccine.
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