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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

#81

Post by arrrg »

StevePerkins wrote: post #6
umvi wrote: post #2

So, according to this paper 34.2-47.5% of US citizens need immunity before the pandemic can be declared over? So best case scenario we can achieve herd immunity with roughly 100M infections/recovered. USA is currently at ~8M infections/recovered, so that means we are roughly 8% of the way to herd immunity (best case). At the current rate of +50K infections per day, that's 20 days per 1M infections, so we need 20 days…

> USA is currently at ~8M infections/recovered CONFIRMED cases. The total number of cases is probably 5-10x that. I live in the Deep South, and honestly I suspect that our curves have fallen simply due to a "limited" herd immunity effect (i.e. the groups of people most likely to catch COVID have already done so in large enough numbers). I certainly haven't observed any significant change in behaviors since the July p…

Deaths are probably more instructive – just to get a ballpark number. If only because deaths are less likely to overlook too many people.

If the IFR is around 1% we would expect around 1,000,000 deaths if one third of Americans have to be infected for herd immunity. So that would suggest the US is 20 percent of the way there.

Given the haphazard way of calculating these numbers I would, however, put huge error bars around some (something like ±15 percentage points at least).

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

#82

Post by majormajor »

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.

You would have to increase restrictions for the vulnerable group because if you allow them to mix at all (even at today's levels) with the "free spreading" group they are going to have much worse odds than they do today. Since you're intentionally trying to increase the proportion of sick people in the less-vulnerable group. People like the "grandma living with family with school age children" or the "30 year old immunocompromised cancer patient with a roommate" get fucked if all those people around them (and around them, etc) simply go back to normal and you don't more actively isolate them.

This might not be a terrible idea, though, if compared to a several-year-extension of what we have now... because over time, the cumulative probably of exposure for the vulnerable will just keep rising and rising if we stay at something like the status quo.

But... that's where things like vaccine and treatment development come in. If a vaccine makes catching it much less likely in 6 months, or treatment improvements make it much less deadly even for the vulnerable in six months, then it's worth spending another 6 months in the current situation.

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

#83

Post by Buttons840 »

tzs wrote: post #70
e40 wrote: post #14

Earlier quoted context omitted.

I wonder if this also means that only 35% of us need a vaccination to declare it over. I had previously read 60-70% were needed and that 35% of Americans get a flu shot. That depressed me. EDIT: seriously, downvoting this comment? Can't imagine why and would like to know.

I don't understand why more people do not get flu shots, unless they have no medical insurance and cannot afford the cost. It's not always effective, because they have to predict when they make it what strains of flu will be prevalent in the next flu season, and they don't always get that right, but in that case you are no worse off than if you had not gotten the vaccine. But when they do get it right, it can save yo…

Aren't flu shots usually free? The last few I've gotten were.

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

#84

Post by Animats »

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/10.1101/2020.04.14.20062463v...

[2] https://abc7ny.com/coronavirus-testing-antibody-new-york-ny/...

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

#85

Post by hcknwscommenter »

jwlake wrote: post #62
hcknwscommenter wrote: post #58

Earlier quoted context omitted.

Because no demographic has been demonstrated to have a 99.99% survival rate?

Source? 0-4 and 5-17 are definitely that high. The 18-45 demo is different, but there's a lot more heterogeneity in that population as well. https://www.cdc.gov/nchs/nvss/vsrr/covid_weekly/index.htm

I cannot fathom how your link could possibly support your contention that 0-4 and 5-17 are "definitely" a 99.99% survival rate (IFR of 0.01% or 1 fatality out of every 10,000 infections). I suspect you are misreading the table? Care to elaborate?

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

#86

Post by joshuamorton »

just-juan-post wrote: post #27
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 This seems like something you made up. Can you cite your source? How exactly does your rule apply to non-humans? What "health measures" do packs of wild horses take when disease comes to the herd?

When cows get mad cow, you quarantine and then kill potentially infected cows. Wild horses have behaviors. They may not change their behaviors when they find a virus, but that doesn't mean that the reproductive rate is independent of the horses behaviors. It absolutely still is.

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

#87

Post by Buttons840 »

bigbubba wrote: post #39
jackpeterfletch wrote: post #30

Earlier quoted context omitted.

This is fag packet math, so I'll spare any exact figures. But if the second wave data for the UK is anything to go by, confirmed cases vs actual cases was at _least_ 5x for the first wave. There obivously are other factors, but with increased testing that multiplier only climbs, bringing herd immunity numbers actually within reasonable grasp. I strongly suspect there have been similar effects in the US.

(People scribble on cigarette packages? Aren't those waxed cardboard or something? I wouldn't expect a pen to work well on those.)

I carry a Fisher Space Pen in my pocket with my keys. It can write on wax paper. The ink cartridges are pressurized.

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

#88

Post by rimliu »

hcknwscommenter wrote: post #58
hammock wrote: post #23

Earlier quoted context omitted.

Why the massive downvotes?

Because no demographic has been demonstrated to have a 99.99% survival rate?

I think in Italy they had 100% for 10-19 bracket.

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

#89

Post by watwut »

war1025 wrote: post #51
watwut wrote: post #47

Earlier quoted context omitted.

> Also I've lost faith in the "we're not doing enough testing" argument since we went and tried to get tested and they turned us away. That does not imply that there is enough testing. That just implies that your doctor or health care system is unwilling to test someone in your circumstances. "Not doing enough testing" is not referring to just test kids not being available, it is also referring to health system polic…

I guess to clarify, it has been my impression that the healthcare industry are the people telling us we are not doing enough testing. We attempted to get tested and they said no, not worth the bother. That seems contradictory to me.

The epidemiologists and some in healthcare industry are saying that.

The reason is not that some people are not willing to get test. The reason is also capacity, aldo policies on who is allowed to get test etc. Your case is literally someone who should be tested and was not, hence "not enough testing".

Here, I can get comertial test if I am willing to pay. No one will send me home. And if I was in contact with covid infected person, I get test for free (it is mandatory). And if I live in household with sick person, I have mandatory quarantine.

Sounds like where you live is no contract tracing and thus not enough testing.

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

#90

Post by School-Cotton »

matthewdgreen wrote: post #69
StevePerkins wrote: post #16

Earlier quoted context omitted.

I think the common perception on HN, Reddit, etc is that COVID spread in the U.S. is primary a matter of conservative people flouting its seriousness. I understand the satisfying appeal of that picture. However, I'm looking at my local health department's ZIP-code-by-ZIP-code infection map of the metro area. And it seems almost entirely correlated with poverty, not privilege. Infection spread seems mostly due to "ess…

I think the reason that HN, Reddit et al. have this impression is that state policies in conservative states are explicitly less restrictive than those in less conservative states. Florida just removed all stadium event attendance limits, for example. Within any given state there are all kinds of political beliefs and economic situations that may be more or less correlated with spread, but state governance is a very…

Is there any evidence that level of restriction correlates with severity of outbreaks, though?
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