[ExI] The Japanese mystery: why so few COVID cases?

[Rafal Smigrodzki]

On Sun, Jun 28, 2020 at 10:30 PM Stuart LaForge via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

>
>
> https://www.embopress.org/doi/10.15252/emmm.202012481?fbclid=IwAR3YClOFxx3Vy6hOD0VqLCynrTxRQxrUigVvLfMhkxRqHPxST9VdEhGWSlk&
>
> --------------Excerpt------------------------------------------
> Despite early exposure, its dense and aging population, and little
> social distancing measures, Japan reports low infection and low death
> from COVID‐19. Here, we speculate on and discuss the possible reasons
> that may account for this anomaly.
>
> There is a lot of interest brewing as to why Japan has such low
> numbers of confirmed infected cases of the COVID‐19 disease, caused by
> the SARS‐CoV‐2 virus (Fig 1), despite its high population density
> (over 6,100 persons/sqkm in Tokyo, 2.4 times higher than New York
> City) and large percentage of high‐risk individuals over 65 years of
> age (about 26%, compared with 15% in the USA). In Singapore and Hong
> Kong, rapid and strict quarantine rules and contact tracing have
> helped to “flatten the curve”. In South Korea, mass testing and
> quarantine measures appear to have reduced the rate of new cases.
> However, Japan has not engaged in expansive testing, contact tracing,
> or strict quarantine measures and yet is reporting a slow growth rate
> of infected persons and a death rate that is currently just 1/10th of
> world average. It is difficult to make direct comparison of infection
> rates, because the number of tests per capita varies dramatically
> between countries. However, this low death rate cannot be simply
> explained by lack of testing or reporting, as no surge in death from
> respiratory syndromes has been reported either.
> -------------------------------------------------------------------
>
> Is it due to differences in the prevalence of underlying conditions?
> This one has me stumped.
>
>
### Graphs of per capita cumulative infections and deaths on

https://ourworldindata.org/coronavirus-data-explorer?zoomToSelection=true&casesMetric=true&interval=total&aligned=true&perCapita=true&smoothing=0&country=~USA&pickerMetric=location&pickerSort=asc

are incredibly interesting.

Why are there orders of magnitude differences between countries that are
presumably providing reasonably honest statistics, so we are talking about
actual differences rather than fakery?

There is hardly any pattern - high-density population, mask wearing,
lockdowns don't seem to be correlated to outcomes, or at least are swamped
by other, order of magnitude more powerful factors. Race may play a role -
South-East Asians, the Han, seem to be doing much better on average, than
Europeans and Africans outside of Africa. But even among Europeans there
are enormous differences that are hard to pin on something specific.

My guess is that there are regional differences in the rates of
pre-existing immunity to Covid-19, driven by rates of prevalent coronavirus
infections, and perhaps by race. There are some genetic determinants of
response to coronavirus infections. That's why the Japanese can survive
their metro while the New Yorkers get wiped out in theirs.

My Nebula account told me I don't have the protective alleles, so my
personal genetic risk of being harmed by the Wuhan virus is slightly above
average.

Rafal
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