
Why herd immunity to Covid-19 is reached much earlier than thought - stimme
https://www.nicholaslewis.org/why-herd-immunity-to-covid-19-is-reached-much-earlier-than-thought/
======
acqq
Just note: written by "Nicholas Lewis, an independent Climate Science
Researcher, based in the UK."

That is, this Lewis is Lewis from all "Lewis and Curry" papers, which are
known to be among the favorites of various climate denialists.

Here is a non-inclusive list of Curry's misinformation:

[https://www.skepticalscience.com/skeptic_Judith_Curry.htm](https://www.skepticalscience.com/skeptic_Judith_Curry.htm)

It seems that Lewis is "independent" but managing to more formally support
these activities, writing papers with Curry.

Which doesn't mean that what he writes now in this article shouldn't be
evaluated on its own merit -- it's just that everybody's "prior" for the
expectations can be reasonably adjusted: personally, my first reaction was
"well, interesting". My second reaction was "now, let's see who's this guy".
My third reaction was... I've decided I personally won't spend much time
investigating his claims, and I won't hope for much to turn out to be true,
based on these (my own) priors. But it's only my own preference.

Also personally, the first time I've read the arguments "Sweden was soo
different in measures" I almost believed it. But then I've just checked
myself: their universities and schools were also closed at the time when most
of the Europe had theirs closed too (the kindergartens weren't -- that's at
least _something_ different). Their workers also worked from homes. There was
a lot of limiting of the contacts, even when politicians didn't made laws or
orders or something for that. I could conclude that what happened in Sweden
was definitely not what seemed that those who made the "difference" claims
implied.

So reader beware. Check what is claimed as premises, and check if even that is
true, before proceeding. Also carefully compare the real numbers. The last
time I've checked, Sweden had more deaths per capita from Covid-19 than the
U.S. and it's still open how much they have not counted and not reported:
still, even comparing these reported, there were something like 4 dead Swedes
for every 3 dead U.S. Americans, on average, even if it appears that Swedes do
live a bit more healthy (~3 years longer life expectation, before). At least
they did 40% more tests per capita than the U.S. up to now.

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weare138
Maybe someone here knows the answer but doesn't the 'herd immunity' theory
assume we build a long term immunity to the disease in question after being
infected? What happens if COVID turns out to be like the influenza virus and
constantly mutates or like ebola where our immunity is temporary?

~~~
lmilcin
Imagine a world where only 1% of population is ever leaving homes and 99% is
forever chained to their desks.

It would seem that it would be enough for only that 1% of population to build
immunity to largely stop transmission of the virus. Of course, it would still
be possible for somebody to move the virus from home to home without getting
infected, but the idea is that you will not get a pandemic from that because
it would not be enough to sustain it.

The whole premise of article is that the population is not homogenous and
different people are responsible for transporting viruses in different way. If
a small proportion of population that is outsize contribution into
transmission gets immunity, then the entire population benefits much more than
if these people were part of completely homogenous population described by
simple equations.

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cozzyd
Considering that the estimated population fatality rate in Bergamo Province is
~0.6 percent (from e.g.
[https://www.medrxiv.org/content/10.1101/2020.04.15.20067074v...](https://www.medrxiv.org/content/10.1101/2020.04.15.20067074v2)),
either the IFR there must be much higher than elsewhere (maybe an older
sicklier population or something)? or ~50-60% of the province must have been
infected.

I am interested in the predictions of herd immunity from mass agent-based
simulations, such as the CityCOVID model used by modelers at Argonne national
lab (can't really find a good public reference and the slide deck I've seen
about it is not public, but it's based on
[https://github.com/Repast/chiSIM](https://github.com/Repast/chiSIM)).

~~~
majewsky
> either the IFR there must be much higher than elsewhere (maybe an older
> sicklier population or something)?

Overloaded ICUs as far as I'm aware.

~~~
rasz
What good is ICU when nobody survives it?

Italy Cremona
[https://www.youtube.com/watch?v=rfkbv_WQtn0](https://www.youtube.com/watch?v=rfkbv_WQtn0)
Italy Bergamo
[https://www.youtube.com/watch?v=_suhYeWEcJg](https://www.youtube.com/watch?v=_suhYeWEcJg)

------
loopz
Due to people getting infected, dying and public recommendations, Sweden and
other places lower R by behaving as in lockdown, even when partially they
still get hit hard twice. Don't see this paper adress change of behaviour
after "Italy".

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redis_mlc
HN: told you so.

The Sweden paper results matches the Bay Area to a T.

(My estimate is that the Bay Area already reached herd immunity in March based
on corona arriving in Dec. and flat hospital rates in the local dashboard.)

[https://www.sccgov.org/sites/covid19/Pages/dashboard.aspx#ho...](https://www.sccgov.org/sites/covid19/Pages/dashboard.aspx#hospital)

~~~
greesil
I'm sorry, but the estimates of covid-19 IFR range to over 1% to 0.1%. Out of
~2M people in Santa Clara County, the death toll is 129 as of today. Bump that
up because some people died at home, but let's start with 129. If the IFR is
~0.5%, that means ~26K infections. 26K / 2M is 1.3% infected. And you think
we've reached herd immunity here? The blog post predicts herd immunity at
~25%.

~~~
kyran_adept
The same as you assume some people died at home, some people got infected
without symptoms at home and are now recovered. Unless you do a mass test of
antibodies it will be hard to estimate the real number of infected and
recovered people.

~~~
fspeech
That is why gp used an IFR to estimate the number of infections. They already
took untested infections into account.

