Breaking News: Herd Immunity Still Important

Rugbyologist

More Articles

About Josh

Welcome to the home of the rugbyologist. Come along as I wander far and wide (and near, too), stop to smell the roses of intellectual fancy, and...

View Josh's Profile

Josh Witten

Herd immunity describes a situation where so many individuals in a population are immune to a disease that the disease cannot maintain itself in that group thus preventing epidemics. Herd immunity is also critically important to protect those who cannot or have not had the opportunity to develop immunity to these diseases. Despite the fact that vaccination is a rare situation where both the rational self-interested act and the selfless charitable act are one and the same, vaccination rates have been dropping due to baseless fear-mongering that vaccines cause autism. This purported connection has been repeatedly disproven by science and thoroughly rejected by the US Vaccine Court.

Science has once again stepped in to show the value of herd immunity. In a theoretical study in PLoS One, Guy Katriel and Lewi Stone look at the effect of herd immunity on pandemics. They demonstrate that the probability of a pandemic increases non-linearly as immunity levels in a population decline.

In particular, we note the dramatic nonlinear increase in attack rate as
a function of the percentage of susceptibles initially present in the
population.

Small decreases in herd immunity have potentially large consequences in terms of disease.

Assuming , the attack rate (continuous line) is plotted as a
function of the initial fraction of susceptibles in the population. An epidemic will not trigger
unless the initial susceptibles are greater than , due to herd immunity. The dashed line shows the
naive prediction for the attack rate, obtained by extrapolating linearly
from the attack rate for , which can be well below the theoretical estimate.

Comments

Herd immunity still important? Sounds like some weird sort of group selection fantasy to me! Welcome to the club Groupie Josh!

Steve Davis | 03/16/10 | 23:43 PM

Steve, everything sounds like a weird group selection fantasy to you.

Josh Witten | 03/17/10 | 04:41 AM

Is that the way groupies talk to each other?
When can we expect your first anti-Dawkins article?
It's a pre-requisite for full membership!

Steve Davis | 03/17/10 | 05:04 AM

Technically, I already wrote one, but not one, however, that would give you much comfort, as it goes against the hyperadaptionist paradigm, a philosophy also embraced by group selection advocates. The "anti-Dawkins" nature is also rather superficial as I will repeat for the n^th time that Richard Dawkins is not an evolutionary biologist, nor is he a significant contributor to the field. Dawkins popularized of the consensus opinion of evolutionary theory emerging from the modern synthesis. He was the first to explain the implications of the conclusions underlying quantitative genetics and evolutionary biology to the public. Unfortunately, the signal that your obsession with Dawkins sends is that you lack a serious understanding of the principles and intellectual history underlying modern evolutionary theory and research.

Furthermore, herd immunity is not group selection, due in part to both time scales of infection versus group turnover/reproduction as well as ready pathogen migration between groups (i.e., lack of population isolation).

Josh Witten | 03/17/10 | 07:40 AM

your obsession with Dawkins

Surely, is it not Dawkins himself who is the Obsessed One? (Al-Mahwûs, according to the Hedghogatollah)?

Calling Steve Davis "obsessed" is a bit like going to Khartoum and calling General Gordon a fanatic as he is about to be cut down by the followers of the Mahdi.

Erinaceus Europaeus | 03/17/10 | 09:21 AM

Obsession has nothing to do with popularity. It has to do with one's focus on a topic. Steve references Dawkins negatively almost as frequently as Rycharde Manne references resonance positively.

Josh Witten | 03/17/10 | 10:07 AM

Mate, whatever happened to ya sense o' humour?!
All this personality stress is no good for ya (herd) immune system!

Steve Davis | 03/18/10 | 04:36 AM

The alternative hypothesis is that my sense of humor is just fine. Perhaps, it's the jokes that are lacking. Or, perhaps I am just grumpy due to the spate of poor science-ish writing that appears to be going around lately.

Seriously though, focusing on Dawkins undermines any arguments you might make for group selection. It is an interesting question, but Dawkins is not an important figure in the development of evolutionary theory. Focus on the issues, not the man.

Josh Witten | 03/18/10 | 05:23 AM

Boy, am I hitting all the right buttons! If you keep this up Josh, you'll become known as "Pavlov's dog" - I mention Dawkins and you start salivating!
Richard Dawkins.... SEE WHAT I MEAN! WIPE THAT CHIN!
Seriously though, you've to a certain extent misread both the tone and content of my articles. My intention has not been to push group selection, even though I've argued that all natural selection can be viewed as group selection. My main focus has been on the lack of substance behind selfish gene theory, no matter if that has been pushed by Hamilton, Dawkins, White or Elmouden.
And I have to say without a hint of humility, that so far no-one, including you, has made a serious dent in my position, or that of Gerhard Adam who has argued a similar line from a slightly different angle.
It's interesting that in our recent exchanges you've criticised my attitude, but have been careful not to venture too close to the issues.

Steve Davis | 03/18/10 | 19:35 PM

I'm commenting, here, on the perception your approach gives, not its substance.

Steve, I have succinctly (and on occasion not so succinctly) rebutted the central assumptions of your critique of selfish gene theory repeatedly (i.e., your critiques only work in the special case where every single resource in an environment is unlimited).

It is true, however, that no reasoned criticism has budged your personal position one single millimeter. Fortunately, science is not dependent on our individual perception of the quality of our arguments.

Josh Witten | 03/19/10 | 05:31 AM

I have succinctly (and on occasion not so succinctly) rebutted the central assumptions of your critique of selfish gene theory repeatedly...
Not only is that not the case Josh, I see in the article that you provided a link to, that you continue to promote one of the great fallacies of selfish gene theory, the alleged self-replication capacity of genes. One of my core arguments has been that selfish gene theory has been designed to give genes a greater role in evolution than actually exists in reality. This self-replication ability is the favourite ploy. Gene replication, as you well know, is a function of the cell.. But we can't have the cell as the primary level of life, can we? Because that would mean that cooperation is the primary function of life.

Steve Davis | 03/19/10 | 20:31 PM

The issue with Dawkins has very little to do with you. It has to do with the fact that Dawkins is publicly the face of evolution and selfish gene theory, when he has very little to do with the development of the theory. As a controversial figure, this association unfairly reflects on evolutionary theory.

Josh Witten | 03/19/10 | 05:33 AM

...Dawkins is publicly the face of evolution and selfish gene theory, when he has very little to do with the development of the theory.
Dawkins has had plenty to do with the development of the theory;it was he who was the propagandist for the theory, he who gave it a profile. To say now that his association with the theory unfairly reflects on evolutionary theory when he is as you say, the public face of evolution and selfish gene theory, is baffling, it does not make sense. You seem to be suggesting that he has somehow become an embarassment, if that's the case you should be supporting my criticisms. But you can't do that because you support the Dawkins view.

Steve Davis | 03/19/10 | 20:20 PM

Yes, the public face. I did not learn my evolutionary biology from the public face. I have several of the best text books on evolutionary biology and quantitative genetics sitting here on my desk. Dawkins name does not appear on any of them. Instead, they have names like Lynch, Falconer, and Futuyma on them. In the professional, academic context, the teaching of evolutionary theory is not based on popularization, but on the success of evolutionary theory scientifically.

My issue with Dawkins revolves around his emphasis on selection over drift in evolution. This makes communicating the concept of non-adaptive evolutionary processes to the public very difficult. It leads to a great deal of bad science communication. In this focus on selection, you are far more the Dawkins supporter than I. You just disagree about the level.

Josh Witten | 03/19/10 | 20:57 PM

"I have several of the best text books on evolutionary biology and quantitative genetics sitting here on my desk. Dawkins name does not appear on any of them. Instead, they have names like Lynch, Falconer, and Futuyma on them."
And I'll bet that Dawkins is mentioned in at least one of them, probably all.
I know for a fact that Futuyama provided a summary of Dawkins' view. Is that not influential enough for you? And you are ignoring the fact that I have also criticised others involved in the deception.
"My issue with Dawkins revolves around his emphasis on selection over drift in evolution."
I'm puzzled by what you mean here. There might be arguments as to how variation arises, but evolution involves selection, no matter what.

Steve Davis | 03/21/10 | 21:10 PM

As I recall Futuyma uses less than one page in a several hundred page text book. He discusses Lamarck at greater length.

I do not ignore those critiques. I simply point out, for your benefit, that your critiques give the appearance of hyper-focus on Dawkins as opposed to the issues.

There might be arguments as to how variation arises, but evolution
involves selection, no matter what.

Its comments like that betray a lack of deep understanding of evolutionary theory and make it hard to accept that you have discovered glaring holes in evolutionary theory that have eluded or been ignored by experts in the field. In fairness, there is virtually no popular evolutionary literature that addresses this nuance.

Evolution is a process driven by four forces. Two reduce variation: selection and drift. Two increase variation: mutation and migration. Dawkins' approach favors selection over drift as the most important force driving evolutionary change. I suggest that he is over-enthusiastic in his application of adaptive narratives to most evolutionary results.

You should read the writings on the implications of neutral theory and nearly neutral theory by Motoo Kimura, Tomoko Ohta, or Michael Lynch (more recently).

Josh Witten | 03/22/10 | 05:52 AM

"Dawkins' approach favors selection over drift as the most important force driving evolutionary change."
Are you really suggesting that a mathematical process based on chance is the most important force driving evolutionary change? That it is more significant than the ever-present, never-sleeping process of natural selection?

Steve Davis | 03/22/10 | 20:54 PM

Depends on the trait and species in question. The key point is the influence of that chance process must be disproven first, before one can start spinning tales of selection. Chance sleeps even less than selection. Don't be too hard on mathematical processes based on chance. Mutation is also a chance process and is absolutely essential for evolution. It may shock you to learn that this point of view is not controversial in evolutionary theory, although other biological disciplines like genomics and evolutionary psychology have been slow to follow.

Josh Witten | 03/23/10 | 04:24 AM

"Mutation...is absolutely essential for evolution."
I think you're over-excited.
"...make it hard to accept that you have discovered glaring holes in evolutionary theory that have eluded or been ignored by experts in the field."
I wouldn't 'ave raised it myself, cos I'm far too 'umble young sir, but that's just what I've done.

I've found that there is an appalling lack of logical thought by many of your experts, compounded by a drive to deceive. As in the fabrication that genes self-replicate, a deception that you appear to participate in.
I've found that cooperation is regarded by many of your experts as a problem for evolutionary theory when it is in fact the primary function of life itself.
I could go on, but I feel an article coming on.

Steve Davis | 03/23/10 | 18:34 PM

Without mutation, you do not have heritable variation. Without heritable variation, you do not have evolution. I'm not over-excited. I just know what I am talking about.

Please read the moderation rules before that article gets the best of you. This statement:

"...make it hard to accept that you have discovered glaring
holes in evolutionary theory that have eluded or been ignored by experts
in the field."
I wouldn't 'ave raised it myself, cos I'm
far too 'umble young sir, but that's just what I've done.

seems to run counter to point 2B.

Josh Witten | 03/23/10 | 19:02 PM

I've got to admit Josh, you do make me smile!

Steve Davis | 03/24/10 | 22:02 PM

I just know what I am talking about.
You know what you are talking about, but you have not heard of recombination or gene flow? Now I know you have heard of these, so I can only conclude that sometimes you just enjoy being dogmatic, even if that detracts from the discussion.

Steve Davis | 03/24/10 | 22:40 PM

I have replied here in the main thread as this was getting very thin for someone with my broad, manly shoulders.

Josh Witten | 03/25/10 | 02:29 AM

At last, some evidence that the acquisition of a Phd has not completely removed your sense of humour!
But some advice from an old footballer; KEEP YOUR EYE ON THE BALL!

Steve Davis | 03/25/10 | 23:03 PM

On't Telly last night there was a news item about Oxford and Oxford Brookes Universities attempting to contain an outbreak of mumps among students who didn't have their second MMR jab.

Oxford Mail report.

The doctors here in Blighty are very concerned about the loss of herd immunity, especially in regard to Measles, and it's certainly no "airy-fairy" concept.

—

Robert H. Olley
Physics Department
University of Reading
England

Robert H Olley | 03/17/10 | 04:15 AM

Yes. Gene flow cannot introduce genetic variation that has not
previously arisen. Recombination can introduce variation, when it
mutates a segment of DNA (i.e., changes the code). Evolutionary theory
uses the term mutation is a somewhat more sophisticated way than it is
used in the Fantastic Four or X-Men. Mutation is necessary to introduce
new variation - variation that does not currently exist within that
species.

Steve, we would all take your diatribes against modern evolutionary
theory much more seriously if you demonstrated actual knowledge of the
theory your are criticizing. As I would tell a creationist student, I am
not asking you to accept evolutionary theory, but you need to
understand it, especially before attempting a critique at that level.
Unfortunately, you seem to think that you do have such an understanding.

To make matters worse, you have decided what the shape of reality should
be and continue to bend all evidence to fit that shape.

Josh Witten | 03/25/10 | 02:27 AM

...your diatribes against modern evolutionary
theory...
Ah, but that's where you reveal your lack of understanding.
Some of my arguments I developed myself and later found that others, in the field, have presented them also.
Some of my arguments have come directly from others in the field.
So your image of me as some lone misguided soul tilting at windmills is, sadly, way off line.
Your image of evolutionary theory as a unified field that only needs reference to text books of your choosing for all to be revealed, is also way off line. There are many critics of selfish gene theory, and many of those are far more qualified to speak on the matter than you or I. But is anyone really an expert in a field that is still evolving?
And if my arguments against selfish gene theory have been so weak, why is it that your attempts at criticism have been so few and so futile?
But you've managed to get way ahead of yourself here.
Earlier I mentioned "apparent deceit."
I think your readers deserve a clarification. You need to tell them that gene self-replication is a fact, or that it is not a fact and you just gave that impression through careless language.

Steve Davis | 03/25/10 | 22:58 PM

Steve, I regularly discuss debates within the field of evolutionary
biology. Evolutionary theory is an exciting and dynamic field, within
which their are a variety of ideas of varying quality. I have referenced
leading texts for two reasons and two reasons only: 1) To contradict
your claims of Dawkins' influence on the field, and 2) because your
repeatedly demonstrated superficial understanding of evolutionary theory
(e.g., your confusion over mutation and drift and your nonsensical
concluding challenge) would greatly benefit from a basic understanding
of the theory, before you tried to engage it and evaluate the debate at a
significant level.

i cannot imagine a critique of your
hypotheses that you would not consider futile. I have critiqued, found
it severely wanting, and those critiques have not been addressed. I see
no need to keep repeating those criticisms like a scratched record.

I
will give you a tip. The fact that I do not support your conjectures
does not necessarily make me a defender of genic selection (nor does
this statement mean that I am not).

Josh Witten | 03/26/10 | 17:19 PM

"The fact that I do not support your conjectures
does not necessarily make me a defender of genic selection (nor does
this statement mean that I am not)."
So cryptic!
I would have thought that one so proud of his "broad manly shoulders" would have the courage to answer a simple question. The question, by the way, referred to gene self-replication, not gene selection. Perhaps you would like some more time to think about it? It cuts right to the heart of selfish gene theory, so I can understand your reluctance to respond.

Steve Davis | 03/26/10 | 20:52 PM

Personally, I find your default association of "manly shoulders" with "courage" to be both sexist and demeaning to women in general, broad shouldered women in particular, and especially narrow-shouldered men. Your apparent degree of self-loathing disturbs me.

Your question is far to vague to permit a sensible answer. Feel free to revise and try again. I know you think you have figured out a great GOTCHA! question, but unfortunately there is no possible interpretation of that query that is relevant to the "heart" of genic selection.

Josh Witten | 03/26/10 | 21:31 PM

You keep trying to move the discussion away from the difficult question, but there's more to selfish gene theory than gene selection, as you know.
I'll ask the simple question.
Is self-replication by genes a fact?
You appear to have aligned yourself with those who believe it is a fact.
Here's an opportunity to clarify the matter.
Please answer the question.

Steve Davis | 03/27/10 | 01:31 AM

Your childish "triple-dog dare" schoolyard rhetoric makes me nostalgic
for my misspent youth. Your strategy - converting a complex issue
into a simple yes-no question to create the false impression of
dichotomous factions that you can exploit - in addition to the irrelevance of the question to the validity of genic
selection leaves me disinclined to
humor you. Because you do not define "self-replication", nor any parameters for the term "fact" (e.g., time frame, level of certainty, etc.) it is actually not possible to give a coherent answer without great exertions of time and energy.

Genic selection is the name for "selfish gene theory". The latter term is just a popularized bastardization based on the popularity of Dawkins' book. Perhaps, while you are defining "self-replication", you can define what you mean by "selfish gene theory".

Josh Witten | 03/27/10 | 10:20 AM

So I can take that as a "No, I will not answer the question" can I?

Steve Davis | 03/27/10 | 20:36 PM

If you manage to rework it into a sensible question - as I have described above, I will be happy to reconsider my position. Or, you are free to go back to calling me dishonest, a coward, and questioning my "manhood".

On a side note, I know I am annoying, but you really have not been a great spokesperson for the idea that "cooperativity, not competition" is the raison d'etre of life.

Josh Witten | 03/28/10 | 07:39 AM

"you are free to go back to calling me dishonest, a coward, and questioning my "manhood".
But its not me that has been hurling the insults, is it Josh?
You've tried to turn my good natured banter into a "my dick's bigger than yours" exercise, but I'm not coming into it.
Because this was never a "Gotcha!" exercise on my part. I happen to believe that gene self-replication is deceitful, you appear to have endorsed it, I've given you the opportunity to clarify your position. I even gave you a face-saving exit that you were too proud to accept.
The concept was a simple one when you used it as an analogy for ideas replication in the article you linked, it must be simple or readers will not make the connection and the analogy will fail. But now, apparently, a simple question about it has you so concerned with hidden traps that you cannot answer. Suddenly it's a "complex issue" that requires "great exertions of time and energy."
But I think that I, and we, have learned all that we need to know about your position, your pride, and your capacity for self-promotion.

Steve Davis | 03/28/10 | 19:32 PM

Based on the number of page views I get, you may be overestimating my capacity for self-promotion.

In my article on the propagation of slightly deleterious ideas by chance, the concept of replication is simple, because the mechanism for that replication exists and is readily understood. Indeed, right now you are trying to migrate your meme into my idea population.

Your persistent unwillingness to define the term "self-replication" in your question to make sure that we are operating from the same definition would make anyone see a trap. From reading your writing, I would be surprised if the question is not leading to a discussion as to how the present mechanisms for DNA replication evolved. Furthermore, you ask the question from an adversarial position, not a curious one. Please explain what interest I should have in providing an answer to a question that will have me attacked regardless of my answer, as an "imbecile" if "yes" and a "hypocrite" if no.

Josh Witten | 03/29/10 | 03:41 AM

I would be surprised if the question is not leading to a discussion as to how the present mechanisms for DNA replication evolved.
Ummm...I do believe it was you who turned this into a serious discussion of evolution. But that's so far back its assuming historical proportions.
You painted yourself into a corner. We all make mistakes. Get over it.

Steve Davis | 03/29/10 | 16:58 PM

What is so upsetting about me asking for you to define the terms and parameters of your question? Given your recalcitrance, and prior knowledge of your writings and positions, my skepticism is quite legitimate.

I don't know, this corner seems awfully spacious.

Josh Witten | 03/29/10 | 17:38 PM

Comments

Oxford Mail report.

Add a comment

Know Science And Want To Write?

What's Happening

Books By Writers Here

Related Articles Here On Scientific Blogging

Comments

Oxford Mail report.

Add a comment

Know Science And Want To Write?

What's Happening

Books By Writers Here