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[GavJ]

But so what? Eliminating outbreaks should not be your main goal. Minimizing deaths should be your main goal, and they are NOT the same thing.

But they are directly proportional

Nope, deaths from disease are proportional to number of outbreaks.
TOTAL deaths (disease + vaccine complications) are not proportional to outbreaks, but will instead likely follow a complex curve of some sort, due to both having conflicting influences.

[Sergarr]

But so what? Eliminating outbreaks should not be your main goal. Minimizing deaths should be your main goal, and they are NOT the same thing.

But they are directly proportional

Nope, deaths from disease are proportional to number of outbreaks.
TOTAL deaths (disease + vaccine complications) are not proportional to outbreaks, but will instead likely follow a complex curve of some sort, due to both having conflicting influences.

Disease outbreaks tend to kill much more people than vaccine complications, unless you're trying to say that vaccines complications can be in outbreaks too.

[Leafsnail]

That was before I looked up the Italian datapoint, which allowed me to infer some sort of a rough trendline. Before that, it might have been zero!

Holy fucking shit, you were seriously claiming to have performed a "thorough mathematical consideration" without looking at any data at all?  In any case though you should look at all the other European countries with higher vaccination rates where measles is endemic too (such as the UK and France).

I assumed you were using the "herd immunity threshold" cited in various places, except:
1) That's not it for measles. That's on the high end of a 10% range of about 85-95%.

You have provided absolutely no evidence to suggest this is true, while I have provided studies and (as you've conceded) this is cited all over the place (eg by the WHO and almost every other health organization) as the required level for measles eradication.

2) The "herd immunity threshold" is pretty technical threshold that does not really factor in here much. It is defined as "the coverage level where disease would sputter out from a single index case even in a completely otherwise uninfected population.

No it isn't, you have completely misunderstood the concept.
http://jid.oxfordjournals.org/content/189/Supplement_1/S27.full.pdf
It's the vaccination coverage for which each infected case causes, on average, less than one further infection (the number of new infections for each case is referred to as R).  That's what you need in order to prevent the disease from re-establishing itself and becoming endemic (otherwise the number of people infected will increase over time).  It's true that post-elimination epidemics can burn themselves out, yes, but ultimately you really cannot rely on that - if the disease manages to spread into a large enough community you will instead get epidemic cycles, with the levels of the disease fluctuating but never falling to zero (since yes, R will temporarily fall and become less than 1 after an outbreak, but the disease will be able to hang on in a few individuals until the population has once again become susceptible and then break out again)

Note that after considering this factor and many others it was concluded that critical vaccination rates of under 90% could be precluded (see the 9th citation in that article).

This article also includes a few other interesting considerations that the very basic maths that gives the 85-95% does not include, such as the fact that it takes time to give people vaccines, and as such it's impossible to achieve herd immunity in the age group that has not yet had both of their shots for measles.  This means that you need a higher rate in schoolchildren to maintain immunity over the whole population, particularly when you consider the high transmission rate in schools.

This study does conclude that yes, you could theoretically have some groups within your country with R>1 and still achieve measles eradication, but you need to be careful to keep them small or else they will allow an endemic to take hold when their population is above the "critical community size".  Certainly the US has a large enough population to sustain an endemic, so you couldn't allow R overall to be greater than 1 and expect measles to stay eradicated.

ALSO it is often (not always) calculated from computer models, not even actual observations of the infection rate. I don't know if the measles one is observed or simulated.

For the record it's a mixture of both, but I think this is pretty rich coming from someone who did not bother to research a single country where measles (or indeed any other vaccine-preventable disease) is endemic before writing a "thorough mathematical consideration" of the subject.

[Neonivek]

I don't know how we can even have "mathematical consideration" when all we know is

Vaccine Fatalities > 0%

And even practically we don't even know if vaccines are purely at fault or if the person just rolled the dice and it landed on death (which is a shame... but it happens)

[Leafsnail]

It's true that we haven't run impossibly large clinical trials on the effects of vaccines, but we have a pretty good idea of the vaccination rate required to eliminate measles (it's high), and once it's eliminated we will never have to deal with either the disease or the vaccine again.

[Neonivek]

At least we know that the Vaccines killed people instantly and kept the costs down.

[i2amroy]

it's better politically and medically to simply choose one side of the argument and stick to it until proven different.

Why? This is not how science works. Without positive results, you keep an open mind, not "pick something randomly and promote it..." Go ahead, go attempt to submit an article to any peer reviewed journal and tell them "Well I don't really have data for this, but it would be SO HARD to get any, so I just chose this theory by coin flip. Please publish. Kthxbai" and see how that works out.

I admit that as a scientist I'm also not a politician or a medical doctor, though. Can you further explain a reason why it is better for them to ignore the scientific choice here and "just pick one side" instead?

Mainly because people are contrary and don't like being told what to do. We know that regardless of how well vaccines are suggested there are going to be some people who (for a variety of reasons) are not vaccinated. We also know that in the case of more deadly diseases (such as smallpox) there is significant proof that vaccines have now saved more people then they have killed (just compare number of deaths prior to the vaccine multiplied by the number of years since and you get a high enough number that unless a significant portion of vaccinated smallpox people died it's saved more, and that number will only go up with the coming years). As such there is a good medical trend that infers that vaccines should be pushed for, regardless of if we don't know the exact risk/reward point.

If 59,900 people out of 60,000 should be vaccinated to match the actual risk/reward point, and we just tell everyone that they should be vaccinated, there is a good chance that you aren't going to be able to control exactly where the actual population ends up, but saying "everyone should be vaccinated" is more likely to get you closer to 59,900 then actually saying "59,900 people out of 60,000 should be vaccinated", if only to account for the portion that purposely is going against your intended will. This is also compounded by the fact that people are lazy, and if you give them an exception or excuse many will not do it simply because they don't want to take the time/money to do so. It's part of the whole "that will never happen to me" bias, and as such saying that some people don't have to do something will result in a much higher percentage choosing not to do it comparatively than saying everyone should do something. (And since our breakpoint is relatively close to everyone being vaccinated, we only want a small portion to not be.

Also politically it's much better to simply set a rule then try to set a percentage. Laws might have things like exceptions, but they only very, very rarely have a dice roll or raffle in them (the draft being one very rare exception, and even with that everyone is still required to sign up). Similarly people like to see a solid stance on things, not a "do this most of the time, but then do this", type stance, so people who hold a solid value tend to do better off in elections.

To put it simply, we know the actual data point for the risk/reward balance is somewhere near the "most people are vaccinated" end, and saying "everyone should be vaccinated" puts us closer to that end than not saying anything, or saying that only some people have to, simply because we don't really have a solid way of enforcing whatever decision we make upon the populace of the world as a whole.

[Neonivek]

Well most people don't get vaccinated not because they are against vaccines...

But mostly because they find it inconvenient or don't see the need to.

SURE the stupidity of the vaccine myths continue but I doubt they are a large contribution.

Or rather because of Laziness.

I got my Flu shot because I tend to get sick a lot. Which for me is because of bad habits and allergies.

[Sergarr]

It's true that we haven't run impossibly large clinical trials on the effects of vaccines, but we have a pretty good idea of the vaccination rate required to eliminate measles (it's high), and once it's eliminated we will never have to deal with either the disease or the vaccine again.

But you see, for GavJ, the only people that matter are the people that exist now. Fuck the future generations! They can die all they want, it's only us, the glorious present generation that truly matters!

[Teneb]

It's true that we haven't run impossibly large clinical trials on the effects of vaccines, but we have a pretty good idea of the vaccination rate required to eliminate measles (it's high), and once it's eliminated we will never have to deal with either the disease or the vaccine again.

But you see, for GavJ, the only people that matter are the people that exist now. Fuck the future generations! They can die all they want, it's only us, the glorious present generation that truly matters!

Present-timer master race represent.

[GavJ]

Holy fucking shit, you were seriously claiming to have performed a "thorough mathematical consideration" without looking at any data at all?  In any case though you should look at all the other European countries with higher vaccination rates where measles is endemic too (such as the UK and France).

I stated quite clearly in the OP that the OP was about the case study of measles in America in 2014. Researching countries with lower rates of vaccination is not really relevant for the main question of "should our American 2014 policy be to push people to vaccinate higher than the current 90%?"

Since then, the thread has progressed to broader worldwide and more generic discussion.

-----

Regarding endemic disease and herd immunity thresholds, there are several considerations to take into account:

1) First of all, we have to consider that it is not actually necessarily needed to wipe out endemic disease in someplace like the UK YET, while we are still waiting on places like India with much higher population density, worse sanitation, and worse healthcare still being at 70%ish (IIRC) coverage. Even if there is endemic UK disease, if it's only among a few hundred people, most of whom are documented, then they present little threat to significantly spreading the disease elsewhere.

You  have to consider the possible strategy of "Wait until all major countries that have air travel and contagion between them are within reach of possibly achieving wipeout levels of vaccination, and then simultaneously push up to those levels when everybody is ready" to actually achieve the wipeout.

Until then, you case the possibility that you are over-vaccinating (in terms of overall deaths from vaccines vs. disease) and killing unnecessarily many people while you are sitting around waiting for other countries, in the name of eradication which you already know isn't possible yet until those other countries catch up.

2) Ignoring #1 for now, the herd immunity thresholds published by the CDC and WHO are also NOT the levels at which endemic disease is containable. They are the levels at which outbreaks are not supposed to occur anymore.  These are different things, for multiple reasons:

a) The reproduction ratio assumes a completely uninfected population (which stops being true after just the second infection and becomes progressively inaccurate)
b) The ratio assumes zero natural immunity (same story)
c) The ratio assumes natural spread with no government intervention (yet in reality we do have government intervention of course)
d) The ratio also often assumes pretty dumb behavior with regard to staying home when sick, etc. although this varies depending on who is simulating the ratio and what parameters they choose.

In reality, all of these and other factors can and do push the actual reproduction ratio way down below theoretical starting levels as an outbreak grows. Thus, outbreaks can and do reliably fizzle out even with basic reproduction ratios well above 1.0

Not infinitely above 1.0. At some point, it will overwhelm these factors and become endemic. But that point is not the same point as that suggested by herd immunity thresholds. It is X% lower, which experts might know, but since they don't publish those numbers, we can only make educated guesses in the thread. X is definitely > 0 though.




I am also confused about why you're arguing with me about "completely misunderstanding the concept" and yet later in the same post mention that the studies you cited discuss exactly what I'm saying above (that eradication can occur / endemic be avoided above ratios of 1.0). If you're hinging this entirely on this "critical community size" concept, you need to really expand on that a lot more, because from my understanding, the entire U.S. is not a "community" in that sense.

[Neonivek]

"should our American 2014 policy be to push people to vaccinate higher than the current 90%?"

Isn't the vaccination rate for measles in the USA like... 80%?

[GavJ]

Mainly because people are contrary and don't like being told what to do

Uh... so therefore the best policy is to issue a blanket declaration that "this is what everybody needs to do. And there will be punishments if you don't. And don't ask us to prove that this is actually best."

The rest of your post doesn't really line up with the claim at the beginning of it...

(except the somewhat separate part about ongoing benefit of eradication, for which please see my previous post above this one)

But you see, for GavJ, the only people that matter are the people that exist now. Fuck the future generations! They can die all they want, it's only us, the glorious present generation that truly matters!

No, I am taking into account future generations. As I have said about 10 times now, the optimal vaccination rate is whichever one of the two is higher:
1) Balanced risk/reward point.
2) Rate at which endemic disease stops occurring (not the same as herd immunity threshold, see previous post).  Possibly only relevant if/when other countries are also ready to achieve this level, but that's a tangential debatable point.

Which is indeed prioritizing the (potentially infinite) number of people in future generations, since #2 overrides #1 if relevant.

Isn't the vaccination rate for measles in the USA like... 80%?

90.8% as of 2012

[Leafsnail]

2) Ignoring #1 for now, the herd immunity thresholds published by the CDC and WHO are also NOT the levels at which endemic disease is containable. They are the levels at which outbreaks are not supposed to occur anymore.  These are different things, for multiple reasons:

a) The reproduction ratio assumes a completely uninfected population (which stops being true after just the second infection and becomes progressively inaccurate)
b) The ratio assumes zero natural immunity (same story)
c) The ratio assumes natural spread with no government intervention (yet in reality we do have government intervention of course)
d) The ratio also often assumes pretty dumb behavior with regard to staying home when sick, etc. although this varies depending on who is simulating the ratio and what parameters they choose.

In reality, all of these and other factors can and do push the actual reproduction ratio way down below theoretical starting levels as an outbreak grows. Thus, outbreaks can and do reliably fizzle out even with basic reproduction ratios well above 1.0

Not infinitely above 1.0. At some point, it will overwhelm these factors and become endemic. But that point is not the same point as that suggested by herd immunity thresholds. It is X% lower, which experts might know, but since they don't publish those numbers, we can only make educated guesses in the thread. X is definitely > 0 though.

They don't assume any of these things, did you actually read the article I posted?  Outbreaks fizzle out if you're in a sufficiently small community - that's why, say, the Amish cannot sustain a measles endemic.  The US as a whole is not a sufficiently small community.  What you'd see in the US as a whole would be
- Outbreak happens until R<1 due to the infected
- Number of people with measles shrink, but due to the large population a few cases remain
- R becomes greater than one as more unvaccinated/infected people are born, and the cycle begins again
Now I guess hypothetically you could maybe make R such a tiny amount above one that the "critical community size" becomes greater than 300 million, but I seriously doubt this would require a vaccination level that is much below the herd immunity level, and if you think it would then I would like to see some mathematical analysis or a source to back that up.

I am also confused about why you're arguing with me about "completely misunderstanding the concept" and yet later in the same post mention that the studies you cited discuss exactly what I'm saying above (that eradication can occur / endemic be avoided above ratios of 1.0). If you're hinging this entirely on this "critical community size" concept, you need to really expand on that a lot more, because from my understanding, the entire U.S. is not a "community" in that sense.

Eradication can occur even if some small communities in your country have ratios above 1.0.  Not if your entire country has a ratio above 1.0 (unless maybe your country is really tiny and you don't have much cross-border movement).  Because if your overall ratio is above 1.0 then the outbreak can easily spread across your entire country, rather than being contained in one small community where it will die off.

If you want to understand the concept of a "critical community size" then I suggest you read the article I provided, because that explains it very well in simple terms.

[Neonivek]

Also you could compare Canada to the USA where the only time we have had a Measles outbreak were in poor communities without measles shots.

With the lesser ones infecting about... 2 people.