
The year you were born predicts flu risk - sciadvance
https://directorsblog.nih.gov/2016/11/22/birth-year-predicts-bird-flu-risk/#more-7263
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8ig8
Was hoping I could enter my birth year and get back some risk prediction.

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Senji
If the data is open, kickstart a webpage or heroku or githubio with js.

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sushid
Not sure if it'd be that simple. The authors discuss only a few specific
countries and admit that although the differences in the risk is "remarkably
small, some noise arises from generalization across time and countries" [0].

And if you factor in that they were studying mostly Asian countries, Egypt,
and Germany, there might be even more discrepancies to account for.

[0]
[http://science.sciencemag.org/content/354/6313/722.full](http://science.sciencemag.org/content/354/6313/722.full)

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Zenst
I'm wondering if this is also a factor in transplants and one area of
complications that could be identified prior to transplant. A differing immune
system and white blood cells would explain many failed transplants and also
this might be one instance in which the immune systems of like blood types
differ and effect outcomes. May be more case of not only matching blood type
but also immune system compatibility, with this being once example of how they
differ.

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maxerickson
The understanding of compatibility is already factoring in a great deal more
than blood type, it's just that there is so much variation that donors rarely
match recipients. See the HLA Typing part of this:

[http://www.ucdmc.ucdavis.edu/transplant/livingdonation/donor...](http://www.ucdmc.ucdavis.edu/transplant/livingdonation/donor_compatible.html)

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tominous
> [In 1968] a pandemic of H3N2 influenza, known as the Hong Kong flu,
> completely replaced the H2N2 and H1N1 seasonal influenza strains that
> circulated earlier.

I'm curious about the idea of flu viruses completely replacing each other. Do
they interact or compete for resources in some way? Could we design a very
mild flu which would replace other variants?

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akiselev
It's less like they're competing for resources and more like they're competing
to see which one will survive the longest against the immune system. The human
body is a nearly infinite source of food for pathogens but antibodies aren't
always very precise in the strain they target. False positives are largely
harmless so the B-cells that produce antibodies are even less discriminating.

When you have similar strains of a bacteria or virus, they can all cause the
same immune reaction (which is how vaccines work) but tiny genetic variations
in each strain can also drastically change how effective the reaction is
against variant. Since bacteria/viruses reproduce very vast and the immune
system is very good at its job, you essentially get an accelerated arms race
that heavily favors the survival of the fittest. Even one part per million
difference in probabilities is almost enough to guarantee the dominance of a
single strain.

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tominous
That explains tiny variations, but the article is talking about a shift to a
new variant which requires a different immune response.

The question is why did this new variant "completely replace" the old ones in
the population, instead of just operating in parallel?

The only thing I can think of is that the old flu variants were in decline
already due to herd immunity, but the article seemed to imply there was more
to it than that.

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SamBam
If it turns out that the very first fly virus you're exposed to has such a
large effect on the immune system, it sounds like this could be great news for
developing a better fly vaccine to give as a baby's first shot.

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kodt
That fly virus can be nasty, just ask Jeff Goldblum.

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SamBam
I have no idea how I typed that twice in a row...

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JoelBennett
It's almost too bad there isn't some way of manufacturing all 18 varieties of
hemagglutinin, and wrapping them all into a single vaccine.

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rsync
Do we want to not get the flu ?

I really hate getting the flu ... I hate feeling terrible for 12-24 hours, I
hate missing multiple workouts ... hate hate hate.

However, in recent years I've stopped my (seemingly ineffective) efforts to
avoid the flu at all costs and _further_ have started to appreciate the
positive effects that getting the flu every 12-18 months might have.

In an otherwise healthy adult, what puts your immune system through it's paces
- what gives your immune system a workout - like having the flu ?

What happens to my immune system if I don't give it that thorough workout
every year for ... say ... 40 years ? What kind of immune system do I end up
with at the other end of avoiding the flu for a large chunk of my life ?

Related to that, what else gets killed every 12 months when my temperature
goes up to 102 or 104 for half a day ?

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danudey
> In an otherwise healthy adult, what puts your immune system through it's
> paces - what gives your immune system a workout - like having the flu ?

That's not how immune systems work. This isn't just a round of going to the
gym. Getting a vaccine also gives your immune system a chance to learn and
react, but without the severe degradation of your condition and the
significant risk of secondary infection.

> What happens to my immune system if I don't give it that thorough workout
> every year for ... say ... 40 years ?

First of all, you run less of a risk of getting secondary infection when your
immune system is weakened. Secondly, you run a higher risk of transmitting the
flu to people who can't be vaccinated (for example, babies or the elderly),
putting their lives at risk.

[Herd immunity:
[https://en.wikipedia.org/wiki/Herd_immunity](https://en.wikipedia.org/wiki/Herd_immunity)]

> Related to that, what else gets killed every 12 months when my temperature
> goes up to 102 or 104 for half a day ?

That's the opposite of how your immune system works. While your system is
focussed on fighting off one infection, it's less able to deal with secondary
infections. You can end up spreading your system too thin and your health can
deteriorate much more rapidly.

[Secondary/opportunistic infection:
[https://en.wikipedia.org/wiki/Infection#Primary_versus_oppor...](https://en.wikipedia.org/wiki/Infection#Primary_versus_opportunistic)]

In other words, not getting a vaccine is unwise both for yourself and for
other people.

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smallnamespace
> That's not how immune systems work. This isn't just a round of going to the
> gym. Getting a vaccine also gives your immune system a chance to learn and
> react, but without the severe degradation of your condition and the
> significant risk of secondary infection.

Citation please. I'm somewhat skeptical about GP's viewpoint, but equally
skeptical that you can so confidently dismiss him, given the number of things
we still don't understand about the immune system. For example, doctors still
haven't managed to cure any autoimmune illness, even though we've studied them
for quite some time.

Full disclosure: I suffer from autoimmune illness, and every time I ask me
doctor about my condition, the answer is often 'we still haven't figured it
out'. The sheer complexity of all the different immune cell types, cytokine
signaling, antibody production, etc. is mind-boggling, and is the product of
millions of years of evolutionary arms race.

In particular, vaccines predispose your immune system towards an immediate
Th2-type (humoral) response, while acute viral infection prompts first a Th1
(intracellular) response, then a Th2 response during recovery.

A strong Th1 immune response is generally more effective against viral
illnesses, so it's possible that if you had a different concurrent viral
infection, getting the flu could encourage your body to clear both at the same
time.

Also,
[https://en.wikipedia.org/wiki/Hygiene_hypothesis](https://en.wikipedia.org/wiki/Hygiene_hypothesis)

> you run less of a risk of getting secondary infection when your immune
> system is weakened

That's true, but you haven't shown that getting the flu weakens your immune
system.

> While your system is focussed on fighting off one infection, it's less able
> to deal with secondary infections.

Your citation doesn't actually support your claim. Latent subclinical
infections are real, and it's possible that acute febrile illness can
stimulate the immune system to go after other bugs that have been hiding or
dormant.

There is some evidence that ongoing viral infections can weaken your bodies
defenses against bacterial illnesses and vice versa.

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brazzledazzle
We may not have a complete picture of the immune system but one of these
comments is square in the realm of "not science but sounds pretty good" and
one at the very least in the ballpark of "conventional science we learn in
school". Even if the former turns out to be correct several years from now it
won't have been because of the revolutionary new hypothesis first put forth in
an HN comment. They've done something we all do where we draw conclusions from
our own experience which frequently turns out to be absolutely bullshit.
Humans tease out patterns where there are none.

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sna1l
I feel like while this does open up a lot of new interesting questions, it
could also just be happenstance.

It seems like there would be so many potential factors that could be causing a
distribution like this. But I'm not a scientist, so dunno.

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oska
From a bird flu perspective, 1970 doesn't look like a good year to be born.
Has relatively high contraction rate for both H7N9 _and_ H5N1.

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eatbitseveryday
I'm a little confused. The figures show number of cases. Higher number of
cases = greater risk?

