
The Unforgiving Math That Stops Epidemics - nature24
https://www.quantamagazine.org/the-unforgiving-math-that-stops-epidemics-20171026/
======
smallnamespace
The math makes it clear why giving everyone absolute freedom to choose whether
to immunize or not doesn't work very well.

If everyone else is immunized to the point where there is significant herd
immunity, but immunization has a low but non-zero cost (e.g. feeling crappy
for a few days), then the rational selfish action is to be a free rider and
not immunize.

However, if everyone did that, then herd immunity can collapse down to a level
where there is no herd immunity; people rationally choose to immunize only to
protect themselves. However, given that immunizations aren't perfect shields,
in that scenario, even immunized individuals will be at risk to infections
spreading through the population.

~~~
orf
That's why a lot of things, like liberterianism (optional taxes) and communism
don't work in practice..

Edit: I mean everyone thinking "well someone else will do it, I dont have to",
specifically regarding to paying taxes or contributing to society.

~~~
wonderwonder
In this case would communism not actually be a positive? If the communist
government decided everyone has to get vaccinated it seems the problem would
be solved.

Not an advocate of communism as a whole but it is an interesting mention that
it would if applied by an aggressive state actor go a long way towards
eliminating certain diseases assuming it has the financial resources.

~~~
kevinnk
Communism is not authoritarianism (except maybe in practice). Lots of
communists are essentially anarchists.

~~~
wonderwonder
Unfortunately, all modern implemenatations of communism are authoritarian.
USSR, China and NK. I understand that in theory it should not be that way but
it is.

------
mayneack
I've always wondered why the flu shot wasn't 100% free even without insurance.
It wouldn't surprise me if one insurance company (or a collective of
companies) could lower their net payout by increasing the number of total
vaccinated people. A one day clinic recently that I went to only charged $30
for uninsured people.

~~~
toss1
It would not surprise me if the math actually worked out that it would be best
to pay people $5 or something to get the shot.

It's be especially good if the payout was perhaps $2 to get it but $5 if more
than 50% of the pop in an area got the shot. Maybe manageable with an Etherium
contract?

~~~
mayneack
Yeah, I guess instead of rolling the dice on herd immunity by subsidizing
everyone. they could just offer monetary incentives for their customers.

------
sunstone
This all makes sense except perhaps for the flu. Only about 30% of people that
come down with "flu like symptoms" actually have the flu. On the other hand
the effective of flu vaccines can vary widely from year to year. This is
because it takes months to make all the doses that are needed so the vaccine
make up, which changes every year, has to be estimated in the advance. The
actual prevalent flu though can change significantly by the time flu season
starts.

The upshot is that the public doesn't necessarily perceive the benefit of the
shot because a) they might get what they think is the flu (but isn't) and b)
they might get a variant of flu that was not adequately covered by the
vaccine. Obviously a more universal flu vaccine would help out a lot.

------
vanderZwan
This was all over the news when it was discovered, but for those who missed
it: measles vaccination protects against _other_ illnesses too, because the
measles causes your immune system to "forget" previously learned immune
responses to other pathogens[0].

I wonder if this applies more broadly: if you're already immune to one
disease, it would be reasonable to expect that your body has more energy left
to fight any unknown diseases it comes across.

[0] [https://www.newscientist.com/article/dn27481-measles-
leaves-...](https://www.newscientist.com/article/dn27481-measles-leaves-you-
vulnerable-to-a-host-of-deadly-diseases/)

------
favorited
Anyone interested in these topics should look into the books "The Hot Zone"
(about the first filovirus outbreaks, including Ebola) and "The Demon in the
Freezer" (about several biological agents, most notably Smallpox, and their
potential for use in warfare).

"The Demon in the Freezer" goes into the story of the eradication of Smallpox
in the natural world, and talks a lot about containment of viral breakouts as
well as the role of vaccination.

------
deepsun
Article doesn't mention that flu shots are always against previous year virus,
not current. Developing a vaccine is a time consuming process (even one year
is already a huge achievement).

So I'm still not convinced about flu shots. Other vaccines, like measles, are
clear win, of course.

~~~
doitLP
Huge point. I agree. The flu virus has mutated over loads of generations
before it arrives again (it circles the globe with the seasons). The vaccine
is a total crap shoot.

~~~
geomark
More like a coin flip since it's about 50% effective.

------
aaron695
> They’re about achieving a collective resistance to disease that goes beyond
> individual well-being

We don't get the flue vaccine for herd immunity and never have. I've never
heard this argument from health departments or doctors.

This article seems to be confusing issues.

If the flue vaccine does help others they need to start publicizing that if
it's true. If they are trying for heard immunity they also need to publicize
that.

I don't watch ads but if people can link to any that claim this I'd be
interested. If it was true then the vaccine sellers would be shouting it from
the roof tops I would think.

------
ryanpcmcquen
Great article. They did themselves a bit of a disservice referencing the Flu
shot though. It is the most ineffective vaccine used in America. This would be
more convincing to those against vaccination if they had just left it out of
the discussion.

------
awful
The 1918 flu pandemic killed what, 5% of the world population? The next
predicted pandemic is to be much worse IIRC. Chief Justice Roberts called the
simple efficiency gap math "gobbledygook"; is he, or is he not, willing to say
the same about this math? what if push comes to shove and has to force America
the free individual to be inoculated, saving the herd? This simple thought
experiment highlights we are all connected, there is only the illusion of
individual liberty because the herd would never intentionally let you kill it
off.

------
mitchtbaum
If humans are so afraid of strangers with needles, then why not turn our
efforts to environmental tools for microbe management?

------
ashwinpp
I have a counterpoint for discussion against taking the flu vaccine based on
the facts we know, and a two independent assumptions I make.

We know that influenza is different from other viruses because 1) There are
many strains of influenza, it has a high mutation rate 2) Flu vaccines are
based on a forecast of likely strains and typically cover only at most 50% of
the strains in a given year [1]

Now let us make the following assumption - Actual flu infection boosts
immunity after recovery from the infection compared to vaccination (perhaps an
analogy would be how muscle recovery happens after microtears after a strength
training workout with heavier weights).

In which case, one might conclude - Since a stronger immune response is great
against a fast mutating virus and around 50% of strains are not covered by
vaccines anyways, that the benefit of boosting immune response against future
infections (beyond the current year) outweighs cost of getting infected and is
a better choice than getting immunized against 50% of the strains with
increased chances of getting flu due to the other 50% anyways

Assumption 2 - Getting exposed, but not infected by flu, increases the number
of strains one's body is immune to. Something sort of like vaccination, but
without taking the vaccines themselves.

For the purpose of modelling, let us also make the assumptions that all
strains arise and propagate independently. That is the strains not covered by
vaccination expose the same number of people unaffected by herd immunity,
while the strains covered by the vaccination face herd immunity.

Now consider the strains covered by the vaccine, whose spread is reduced due
to herd immunity. It is great for everyone vaccinated against the strains, but
for people not vaccinated against it, it prevents exposure from and hence
immunity. This might be a case where the utility of vaccination decreases for
non-vaccinated individuals instead of increasing (herd immunity) as a function
of the fraction of vaccinated population. In other words, the more people
vaccinated for flu, the less likely an non-vaccinated person is to get
exposed, the less likely is he/she to develop immunity towards those strains
naturally. Thus this would prevent population level immunity from arising,
where it would have arisen naturally.

Note that in this scenario, one might question that in the natural course of
events, a certain percentage of population will develop immunity anyways and
hence become equivalent to the scenario where some part of the population is
vaccinated. However there are three major differences. First is that there is
a certain delay between getting infected, spreading to others and gaining
immunity. Thus for the same percentage of immune population, there might be
larger population exposed in the natural course of events. Second is that many
individuals might get infected, transmit and immunized to a strain without
getting infected, thus such an individual gets all the benefits of
vaccination, but might help others get exposed and immunized to a strain. And
third that vaccination is more aligned with socio-economic factors while
infection less so.

To conclude, if any of the two assumptions I state are true, then we should
perhaps not blindly apply the same logic that applies to other viruses for
which we have vaccinations.

[1]
[https://news.ycombinator.com/item?id=15562258](https://news.ycombinator.com/item?id=15562258)

------
suneilp
So now, what am I supposed to think of all those claims that the flu vaccine
is essentially a step or two behind nature.

Then, for me, I worry about the adjuncts and other stuff added to the standard
vaccines as I have autoimmune problems. There are alternative vaccines that
are available but I don't remember their efficacy.

So I refuse taking vaccines unless absolutely necessary until I see viable
alternatives without aluminum, any kind of mercury, and so on.

~~~
apsec112
These fears are based on bad science. The alleged "toxins" in vaccines are
either present in microscopic quantities - micrograms or less - or were simply
never there in the first place. It's like worrying about "sugar being bad for
you" \- which it is, in large enough amounts - because a single grain of table
sugar got into your cereal. Details: [https://sciencebasedmedicine.org/toxic-
myths-about-vaccines/](https://sciencebasedmedicine.org/toxic-myths-about-
vaccines/)

~~~
suneilp
That page was interesting. Yet, I keep seeing conflicting reports stating that
the removal of thimerosal from vaccines to be exaggerated, etc.

