
Genes, blood type tied to risk of severe Covid-19 - rkolberg
https://directorsblog.nih.gov/2020/06/18/genes-blood-type-tied-to-covid-19-risk-of-severe-disease/
======
superbatfish
FWIW, The blood type correlation had already been found by a months-old study
in China. But that was via ordinary blood type tests, not GWAS. I guess it
lends credibility to this method that their findings are consistent with the
other study.

As the proud owner of ~5 liters of type-A blood, I’m less than pleased to see
this finding confirmed.

~~~
sjg007
I presume A+ falls under A... ?

~~~
loa_in_
Yes, the +/\- denotes another, not correlated property. I'll leave finding out
details as an exercise to the reader.

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hprotagonist
In general, i regard GWAS as fishing expeditions that are more or less
guaranteed to find spurious correlations. Von Neumann's old saw about "With
four parameters I can fit an elephant, and with five I can make him wiggle his
trunk." absolutely applies here without other information.

That said, finding associations with ACE2 and blood type regions are not
totally insane!

~~~
rossdavidh
My thoughts exactly. The article seemed to suggest that they looked at a truly
ginormous number of SNP's, which suggests a high susceptibility to the xkcd
"green M&M" type problem ([https://xkcd.com/882/](https://xkcd.com/882/)).

However, the good thing about blood type is that it should be reasonably
easy/quick to do a followup where you examine a lot more patients, or even
just randomly selected individuals, to see if it really holds up. As a type O
person myself, I am hopeful.

~~~
bobcostas55
GWAS studies typically use a p-value cutoff of 5*10^-8 to avoid exactly that
problem.

~~~
glofish
p values cutoff can't salvage that

as a matter of fact artificially raising the cutoff to make the results sound
more convincing is a form a p-hacking

it is exactly the opposite of how p-values work. a smaller p-value does not
make a result more reliable, it makes no sense whatsoever to reject a 10^-7
but trust in 10^-8

the misuse of p-values in the world is rampant - the only people that don't
misuse them are those that do not use them ;-)

~~~
drocer88
See here: [https://en.wikipedia.org/wiki/Genome-
wide_significance](https://en.wikipedia.org/wiki/Genome-wide_significance)

"The most commonly accepted threshold is p < 5 × 10−8, which is based on
performing a Bonferroni correction for all the independent common SNPs across
the human genome"

------
murphyslab
23andMe also reported on their blog that their preliminary data also supports
a protective role of blood type O:

> Individuals with O blood type are between 9-18% percent less likely than
> individuals with other blood types to have tested positive for COVID-19,
> according to the data.

and

> While it is still very early in the study, 23andMe’s preliminary
> investigation into genetics seems to support these findings. Comparing the
> research participants who reported that they tested positive for COVID-19 to
> those who tested negative, our researchers identified a variant in the ABO
> gene associated with a lower risk. (The single nucleotide polymorphism in
> the ABO gene is rs505922, a T at that location is associated with lower
> risk. The P-value for the association is 1.4e-8, OR = 0.88).

See:

* [https://blog.23andme.com/23andme-research/23andme-finds-evid...](https://blog.23andme.com/23andme-research/23andme-finds-evidence-that-blood-type-plays-a-role-in-covid-19/) * [https://www.snpedia.com/index.php/Rs505922](https://www.snpedia.com/index.php/Rs505922)

~~~
hinkley
With those sort of numbers I kind of wonder if there isn't some other gene
that is correlated with type O blood, rather than the blood type itself.

~~~
DoreenMichele
Given how it impacts the blood (clotting), I don't see any reason to think you
need to look for some other explanation beyond blood type.

------
sethammons
> [T]he findings suggest that people with blood type A face a 50 percent
> greater risk of needing oxygen support or a ventilator should they become
> infected with the novel coronavirus. In contrast, people with blood type O
> appear to have about a 50 percent reduced risk of severe COVID-19.

~~~
thephyber
The prior part of the paragraph that you didn’t copy pasta was critical in
understanding context here.

The study didn’t look at blood types directly, but looked at genes which
express as those two blood types, finding that the genes correlate with
supplemental oxygen need during severe symptoms.

~~~
dnautics
Blood type phenotype correlates nearly exactly one to one with their synthesis
gene genotype, so this semantic distinction is not very important.

------
glofish
Wait, first and foremost age is tied to severe Covid-19

Then overall health, how many other pre-existing conditions and ongoing health
issues patients already have.

Then there is the dose and the exposure the patient has.

These are by far the largest contributors.

I find it hard to believe that they have successfully disentangled all these
confounding factors.

Then and only conditionally perhaps the factors that the director lists. In
all, I find the blog a staggering piece of how NOT to communicate, how not to
send the wrong message. Most people will read this as: "blood type A is really
bad"

GWAS in general is weak stuff, even in the cited paper the odds ratios are 1.5
and 1.77 which does not indicate a particularly strong effect. Statistically
may be significant, but in a practical sense not actionable. As far as GWAS
studies go most turn out to be nonsense anyway.

~~~
bobcostas55
>As far as GWAS studies go most turn out to be nonsense anyway.

[citation needed]

~~~
glofish
A continuously updated list of bad genetics studies

[https://massivesci.com/notes/gwas-complex-behavior-bad-
biorx...](https://massivesci.com/notes/gwas-complex-behavior-bad-biorxiv-
genome-wide-association-study/)

the only reason why not most GWASare listed there is because it does not pay
to prove that a GWAS is a nonsense,

it is way too much work to disprove, and you don't get paid/supported for
doing so

~~~
drocer88
Were any of those particular papers disproven, retracted or were not able to
be reproduced?

This paper , "Genome-wide association studies: the good, the bad and the ugly"
:
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4952840/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4952840/)
claims "the vast majority of associations identified by GWASs are extremely
robust statistically and are reproducible in additional studies.".

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neals
How do so many people now their bloodtype? I have no idea what mine is. Is
there a simple test?

~~~
JshWright
It's a common "experiment" run in high school science classes. It can be done
with very little equipment (just a disposable lancet to prick the skin, and a
disposable card to give you the results), and lends itself to interesting
lessons on genetics, antibodies, etc.

~~~
czzr
Dangerous experiment. Must have found at least a few illegitimate children, if
it is done routinely.

~~~
JshWright
That's assuming the students know their parents' blood types with high
confidence.

