I as well, am no medical practitioner, but vaccinations help prevent the affliction of disease on the host, so I believe that they are in line with evolutionary medicine. I don't honestly believe that you can bypass a specific part of the immune system, the entire system works together for a common goal.

Jayne, I think it might be wise to clear up a few confusions posed by your reply.

Most vaccinations are not given into the bloodstream, when you are given a vaccine, say the flu vaccine or Hep B vaccine it is given intra-muscularly. The administering practitioner does not gain IV access and inject you with an antigen. This is potentially dangerous and might precipitate an anaphylactic reaction. Its true that intramuscular injection might also but it is less likely.

In the case of the argument for healthy people just having the disease instead there are many more dimensions to this than that which you ask. 1) Many diseases are likely to be fatal and therefore vaccination is preferable to disease eg. Hepatitis B. 2) Many diseases are unlikely to be fatal or cause long term morbidity such as the flu and therefore vaccination is not preferable to disease in the healthy person. It is preferable to vaccinate in the case of flu for the very young, very old, people with respiratory illnesses, and in the case of the recent swine flu (h1n1) for key medical personnel. Then there are a whole range of diseases in between, many of which are nonetheless very unpleasant.

Would our immune systems be better off if we catch the disease itself, yes, in that immunity conferred is stronger usually from catching the actual disease than by being vaccinated. This has to do with the fact that when we catch a disease our immune systems are exposed to all of the antigens the disease carries, when vaccinated we might (depending on the type of vaccine) be exposed to only some or one of the antigens the disease carries. However this is often more than sufficient to allow us to produce large, quantities of antibody rapidly, should we ever encounter it again.

We have evolved over millions of years alongside disease and as far as I can see the only harm vaccination might do to us evolutionarily, is to prevent natural selection from selecting the most disease resistant of us to carry on our genetic lineage and increase disease resistance in future generations. However as many of us will potentially reproduce before encountering a disease this argument is weakened. We have used technology to solve a lot of our problems, we are not using natural selection, and vaccinations are one of the key technologies in medicine. They are in fact far more successful in reducing the harm of the diseases they work against than almost all treatments for those diseases.

This opens up a far larger debate about the role natural selection has for modern humans. Perhaps it will result in our increasing reliance on technology to survive. We do not after all deliberately choose a hairier partner in order to produce offspring with, if we live in colder climates. We use warmer clothing. In this regard my contention is that natural selection is far less potent in humans than in probably every other species on earth. We evolve our behaviour not our bodies to cope with our changing environment and we do this by education not natural selection. I would even go as far as to say that natural selection and indeed evolution itself may in fact stop altogether in humans as the pressure to adapt our bodies to our environment is not really there. We do not survive by being fitter, we survive by being more intelligent and inventing solutions to our problems, i.e. the problems of shelter, heat, light, food are all approached from a tecnological standpoint not a biological one.

To widen it even further; Is the human race losing its own genetic diversity? Yes, in that we travel around the globe, we partner with and produce offspring across racial lines, one might envisage a world in the distant future where many of the distinct races no longer are distinct but instead everyone is more alike, although this might take quite a long time.

Coming back to medicine, the need to alleviate the suffering of the people of today will always take precedence over the evolutionary needs of future generations, even if this might seem short sighted. Some might even say that our ability to prevent disease from regulating the numbers of people on earth may be our very undoing. Unpalatable though population control discussions actually are to a surprisingly large number of people, all of the recent furore about the environment, climate change and the like is really about population size. If we had 10 million people on earth then we would have a sustainable population even if we individually had a remarkably high standard of living and consumed vast resources per person. A population of 9 billion by 2050 is a big problem.

Jayne, I initially had difficulty understanding the aim of your question, but on further readings I have tried to break it down in stages and hopefully provide the answer you seek.

Firstly you said, in relation to vaccinations in general:

"I am...a skeptic in terms of a one-size-fits-all approach."

I understand what you are trying to say is, you believe that a single vaccine, for say Polio, may not work for everyone because each individual may have evolved a different immune system in relation to Polio as an example.

I think what you are missing is that the Polio strain is the same whoever it infects and thus the immune response required will be the same. Therefore if we create a vaccine for a particular pathogen strain we would expect the immune response to be against that strain. Whether two people have differently evolved ways of responding to that strain is inconsequential, the reality is they will respond to it accordingly. Everyone's body will try to fight of foreign invaders and once they have done it once their immune systems learns to respond or builds up a strength of response if ever they meet the same invader.

A vaccine is just a way of safely introducing someones immune system to a potential invader and thus giving them the tools to respond themselves.

You then go on to say:

"I would suggest that vaccinations may not fit in with evolutionary medicine as the disease is entered straight into the blood stream, thus by-passing other (potentially important) components of the immune system."

From this I think you are trying to argue that pathogens enter the body through cuts, grazes, inhalation, absorption *etc, etc...* and by giving vaccines via injection into blood stream or muscle that it somehow bypasses the correct path for the immune system to respond to. You postulate therefore that a vaccine should be given in the same way as the target pathogen enters the body.

To address this you must understand that the immune system is not distinct for the nasal passage or lungs or gut or skin. It is the same system throughout the body, thus introducing a vaccine to the body is always done in order to give the best immune response i.e. Get as much of the vaccine to come into contact with the immune system. If you just inhaled, swallowed or rubbed onto the skin then other defence mechanisms (e.g. Gut enzymes/acid) would break the vaccine down and not enough would get through to cause a sufficient response and you would therefore need to provide larger doses of vaccine in order to illicit the correct response. So the current methodology is such that we can use smaller doses, which is inherently safer and more pleasant for the recipient and yet achieve the correct response. Whether a pathogen exists in you toe or your nose your immune response will be the same and it will respond according to how much pathogen exists in your body.

"I would love to hear any biological arguments supporting a positive relationship between vaccinations & evolutionary medicine."

Vaccinations just elicit a response that has been evolved over many 1000's of years so therefore they are not contradictory to evolutionary principles, they are in fact in synchronisation with it. If there was no positive relationship then vaccines simply wouldn't work in the way that they do and wouldn't be the success story they have become.

Important Note: I have not mentioned that some people have over-sensitive/under-active immune responses compared to the general populus. These are often caused by other medical conditions and not as a process of being on a different evolutionary branch to everyone else. If by some chance someone has developed a predetermined immunity to HIV for example then it would be hard to identify because they either; would not get ill or they haven't contracted the virus and thus their immunity remains anonymous. If it were to be discovered then there may be reason to assume we could learn something from it and use that to develop a vaccine for it.

I am not a medical practitioner, but my opinion is that vaccinations are in line with evolutionary medicine because the effect of the vaccine is to prevent the virus / disease from affecting the host, thus causing the host to either evolve immunity to the virus, evolve resistance to the vaccine or for the virus to evolve resistance to the vaccine.

The human immune system is a multi-facet system and cannot be "bypassed". The system however, can react in benign ways allowing disease to co-exist with the immune system. HIV is one such virus which is able to co-exist and infect the immune system itself. The reaction of the immune system is not always positive.

I don't think evolution theories have anything to do with the mechanism a vaccine is deployed. The choice of inhaling versus injection is subject to how affective the vaccine is absorbed by the body.

I have some medical training although am not a medical doctor. I do not understand the relevance to evolutionary medicine, or really what this means.

Vaccines work by causing the body to "sample" an antigen (harmful agent, be it a virus or part of one, a bacterium or part of one etc...) and effectively program a set of immune cells to produce antibodies, little pieces of protein which specifically lock onto and deactivate the harmful agent when it is next encountered. Our body does this any time a disease attacks us, a common cold prompts production of antibodies and we overcome the virus. Having antibodies already i.e. being immune by having had the disease before, or by being vaccinated, speeds up this process and may prevent the diease from taking hold in the first place.

Various vaccines are adminstered in different ways. Polio vaccine for example is swallowed, flu vaccine is injected into muscle in the upper arm or buttocks. As far as I am aware few if any vaccines are injected into the blood, but instead into muscle. The reason for this is it allows the deactivated virus (or particles of virus) which comprise the vaccine to sit in the tissue for enough time to develop an immune response. Vaccines are administered in the way which most effectively causes the patient's body to have the appropriate response and sample and store the antibody it needs for future defence.

http://www.amazon.com/Why-We-Get-Sick-Darwinian/dp/0679746749

I found this book to be a good introduction into Evolutionary Medicine.

It's about recognising when medicine is helpful & when it may potentially be unhelpful to the body from an evolutionary perspective. I think most people are primed to reach for the medicine cabinet the minute they feel a sniff, but perhaps it's time we stopped doing that? For example, getting a raised temperature is a normal part of the immune system when fighting an invader & in many circumstances, instead of reaching for the paracetemol, we'd probably be better off leaving the body to get on with it.

My questions for an evolutionary biologist would be along the lines of asking if vaccinations actually help the immune system long term or do they potentially mess it up? Is there an argument for vaccinating via the normal ways disease enters our bodies - via the respiratory system, the eyes, the digestive system, instead of directly into the bloodstream? (because apart from things like tetanus, most diseases don't enter our bodies this way) Is anybody doing research in this area? And would our immune systems be 'better off' if healthy people with no underlying medical conditions caught some of the diseases we routinely vaccinate against? On a biological level are we asking for trouble with the blanket silver bullet approach? We have evolved over millions of years alongside viruses & disease, if we attempt to eliminate them all through vaccinations, will our immune systems be worse off in the long run?

I deliberately haven't given much detail because I'm not a scientist so I know I'm out of my depth - I'm a journalist, so just full of questions (I'm not writing an article or anything, I'm just personally interested in this area). I also understand that the immune system is an incredibly complex creature & that the existence of antibodies doesn't necessarily result in immunity, however, if there were any good biologists out there who can enlighten me about whether they think vaccinations are in line with evolutionary medicine, I'd be very grateful.

As I said, I am also sceptical about a one-size-fitting-all approach to medicine & the role Big Pharma plays in vaccinations.

Thank you.

I just wanted to say thank you very much for your thoughtful & excellent answer - you've given me much to think about.

Glad to be corrected about the whole 'bloodstream' thing - that's the result of lay people like myself talking nonsense in a field in which we're scuppered by lack of knowledge.

I completely agree that vaccinations & the relief of suffering have a valuable place, especially where the disease is more likely to cause death / serious complications & they are particularly useful in protecting the vulnerable.

However, my bugbear has always been the blanket immunisation programmes, such as those we inflict on children - what effects are these having from an evolutionary perspective? I just wonder if it's not better for natural selection if we only offer some these vaccinations to vulnerable children & not necessarily all. Yes, it's advisable that all children receive a diptheria jab, for example, but whooping cough? Next we'll be told about the impending doom of chicken pox as that jab becomes a mainstream part of the childhood vaccination programme.

Mixing into this the role of big pharma & it's often difficult for people like myself to decipher objectively what's 'best'. Especially when we consider some of the ingredients of vaccinations such as aluminium & formaldehyde & a distinct lack of research into the long term effects......anyway, that's an aside....I really hope I'm not coming across as one of Ben Goldacre's ill-informed middle-class Islington types, as one feels one might be labelled the minute we start to question 'modern medicine'.......I really do want to absorb every slice of information as possible & strive to remain as objective as I can...

You said: "We have evolved over millions of years alongside disease and as far as I can see the only harm vaccination might do to us evolutionarily, is to prevent natural selection from selecting the most disease resistant of us to carry on our genetic lineage and increase disease resistance in future generations. However as many of us will potentially reproduce before encountering a disease this argument is weakened". Could it not be argued that whether we've reproduced or not by the time we get a disease makes little difference, seeing as we don't pass immunity on to our offspring? Is it not about the certain genetics that have been / will be passed on?

I really appreciate your angle on over-population, which ultimately leads my initial question to morphing into: 'should we be relying more on natural selection than modern medicine?'........now that DOES set me thinking..........

Anyway, thank you again for your considered reply, I really appreciate it.

Vaccines are precisely in line with, and are predicted to be effective by, evolution and evolutionary medicine. Traditionally medicine has overlooked evolution, referring to the a changes in a pathogen's structure by synonyms instead. Viruses and bacteria "adapt," "develop resistance," or "mutate" over time. What medicine means by this is (whether recognizing it or not), an infectious disease evolves. When we adopt the word evolve, we bring the entire conceptual framework--the explanatory power--of evolution; and most importantly, the mechanism by which evolution occurs: Natural selection. In fact, a pathogen experiences the same selective pressure(s) to evolve as does every other living thing.

Take, for example, the flu virus. While of the same family, Orthomyxoviridae, there is a genetic variability resulting in many different strains, or evolved variants of the original. While it is true we know of many of the strains, periodically, a strain will pick up a piece of RNA from another flu virus or evolve to infect a human host where it might have infected another species (the avian, H5N1 virus) for instance. At this point our immune system may not recognize the evolved form and must play catch-up.

Such pathogens and their hosts (or potential hosts) co-evolve. Over many hundreds of thousands of years humans have evolved a very responsive immune system, which continues, no doubt to evolve slowly. We live many, many decades, often beyond child-bearing age. The pressure to evolve a substantially more effective immune system is low. However, pathogens are often short-lived: Hours, days. The pathogen needs to evolve rapidly to survive, especially where there is herd immunity (or other factors) where pathogen survival is low. The selective pressure to evolve is much greater.

So under the evolutionary medicine model, we have two co-evolving organisms (see Table 2, page 423 of this link): Host and pathogen. For the host to keep up with the rapid evolution of the pathogen science offers the vaccine. The vaccination results in an permanent epigenetic evolution of the immune system, enabling the immune system to respond quickly and decisively to an actual infection. A vaccination's mechanism(s) of action is wholly consistent with evolutionary medicine.

But can it not be argued that there's nothing 'natural' (as in natural selection) about artificial immunity & that we're possibly ramping-up the competition between us & pathogens by using an increasing amount of vaccinations? Is this a more dangerous path to take - to 'provoke' pathogens to keep on mutating in order to survive?

What are the evolutionary alternatives? Quarantine?

As I understand it, pathogens don't necessarily want to kill the host & are less 'severe' when they're contained / stopped from being passed from host to host (please excuse my lack of biological terminology). They only mutate to survive when 'provoked' - can it not be argued that vaccinations are artificially provoking them & that we have ignored possible alternatives as a result of utilising cheap & 'efficient' vaccines prolifically in recent years?

Luckily, a forever-mutating pathogen provides a nice bit of continuing work for Big Pharma doesn't it?....

Originally I was excited about this question. First, because I know, as Skrivener urges us not to forget, how important vaccines are to the reduction of human suffering. Second, because I know how important evolution has been to understanding virtually everything larger than the atom: From the chemistry of the gene to geopolitics. Third, because of how little I knew of evolutionary medicine: How the mechanisms of evolution explain or model human health. I wanted to do the research and reading that would allow me to make a contribution. Like all skeptics I love making the cases for vaccination and evolution. I wanted to be part of understanding how the two relate.

Now I am not so excited about this question. When I originally read it, I understood the question to be: Are vaccinations consistent ("in line") with evolutionary medicine. This would suppose the questioner understood both vaccination and evolutionary medicine well enough to suspect there might be an inconsistency...that one might be out of line with the other. It suggested that a non-expert who accepts evolutionary medicine might find it difficult to reconcile vaccination with their view medical view. As this dialogue has continued, it is no longer clear that the questioner intended this at all. I think I misunderstood the intent. I am not sure what the intent was or is.

My question to the original questioner Jayne, just as Richard Stelling asked in his comment: What do you mean when you use the term evolutionary medicine? And, what did you mean by "in line with"?

Since there has been a conversation of sorts, I'm joining in part way through. I may miss some points above, but I believe I understand a little more where you're coming from and can perhaps be of help now.

But can it not be argued that there's nothing 'natural' (as in natural selection) about artificial immunity & that we're possibly ramping-up the competition between us & pathogens by using an increasing amount of vaccinations? Is this a more dangerous path to take - to 'provoke' pathogens to keep on mutating in order to survive?

Firstly, beware of using words such as 'natural'. It's not a very useful term. Everything is natural. Humans, and what we do are natural. Arsenic is an element - you don't get much more 'natural' than that - and so is Mercury, but I wouldn't advocate gargling them at bedtime.

Secondly, natural selection results from the death of individuals before reproduction. So to advocate increased natural selection among humans is to advocate allowing the deaths of the infirm and disadvantaged. Is that what you're intending?

Thirdly, doctors do not arbitrarily throw vaccines out into the population without careful thought, reasoning, debate, and research. Many government, medical, and educational bodies are involved in vaccine development and deployment, not just "Big Pharma".

Fourthly, "Big Pharma" is not necessarily working for the benefit of humanity, but beware because neither are the many misguided anti-vaxers, and well-meaning but misinformed members of the media and the public at large.

Fifth, vaccines use our own immune systems in the way that they evolved to operate to fight disease. Our immune systems have an innate ability to respond to an infection and to create a memory of that infection in order to better respond in future. A vaccine triggers our immune system to respond as if a virulent infection has occurred, when it has not (or has in a very weakened state), and develop an "immunity memory" against that infection. Depending on the type of vaccine, the specificity of that memory (and the exact nature of immune stimulation introduced to the body) will vary.

Our bodies already do this by themselves all the time. Every time you catch a sniffle, and many times when you notice nothing at all, your immune system is working to recognize and prepare to combat pathogens and recognize and not overreact to more innocuous environment agents. It's an especially common part of growing up, and when it goes wrong that's how you get things like allergies - overresponse of the immune system to an innocuous agent.

Are vaccines without risk? No, and the medical establishment have never said so. It is well known that vaccines themselves may result in allergic reactions, for example. A given vaccine is carefully weighed against the potential for harm by the disease vs. vaccine before a decision is made to introduce the vaccine to the public at large. That said, vaccines are relatively safe compared to the diseases they prevent.

Sixth, vaccination does not provoke pathogens to mutate, that is their own innate behavior. Vaccines don't affect natural selection of the pathogen directly, although they prevent selection of humans - but that is how we operate as a compassionate society. Allowing some humans to die in order to allow a given infection to propagate will not prevent that infection from mutating at any later point.

Because it doesn't act on the pathogens directly, vs. say an antibiotic on bacteria, it is possible to eradicate a disease by widespread vaccination, as was done with smallpox. There are several diseases (Polio, for example) that should have been similarly eradicated by now if vaccination was better implemented.

Seventh, pathogens don't 'want' anything. It is possible for infections to reach a stable state where the impact on the population is non-lethal by selection pressures on the host population to develop resistance. At any point the pathogen might then mutate to become more virulent, resulting in more frequent deaths until the population is selected for resistance again. It's also possible for a pathogen to be completely virulent to the point of wiping out most or all of the population - see the contagious tumors currently destroying the Tasmanian Devil population. It might be an evolutionary dead-end for the pathogen, but that's little comfort to the dead population.

Eighth, it's common to forget how our global society has changed the nature of disease transmission. It is now extremely easy for pockets of new, mutated, or non-eradicated virulent infections to be tapped and rapidly spread. The threat is real, and the response must be ready, and where possible implemented in advance.

Finally, many forget that the diseases being vaccinated against are god-damn fucking awful diseases, that - before widespread vaccination - killed many and maimed many others. This includes influenza, not to mention measles, mumps, and rubella, chicken pox, smallpox, etc.

I'm not providing a bunch of references, just writing from my knowledge of immunology, which has faded a little since uni, so I may strike some wrong notes, but I hope I have given you a better overall picture of what's involved.

EDIT: I'm going to address some more points you made earlier.

I think most people are primed to reach for the medicine cabinet the minute they feel a sniff, but perhaps it's time we stopped doing that? For example, getting a raised temperature is a normal part of the immune system when fighting an invader & in many circumstances, instead of reaching for the paracetemol, we'd probably be better off leaving the body to get on with it.

This is a very specific point and unrelated to vaccines. I won't get into it in detail therefore, but I suggest you ask about fever vs. fever suppression in a separate question.

I would say, however, that you can't generalize effectively about whether a given medical remedy (when provided to alleviate symptoms) is preferable or not to allowing the patient to suffer the symptoms. There are cases where providing a treatment is not desirable, as with antibiotic prescriptions in many cases, but nor should we assume that because someone is suffering that is necessarily a good thing and symptoms should not be addressed. You would be best to examine each case on its own merits.

I'm a journalist, so just full of questions (I'm not writing an article or anything, I'm just personally interested in this area).

Are you in a position to write an article? I would think it would be quite interesting, but I would suggest interviewing or corresponding with immunologists and medical professionals directly, and doing more reading on basic immunology and the role of vaccines first so as to approach them with a better understanding. That way you can digest and report the fundamentals for your readers/viewers succinctly and spend the time with the professionals getting to the bottom of issues specific to your evolutionary interest.

http://www.youtube.com/watch?v=pcnCJqDa1us

Please also watch this fascinating series of Richard Dawkins & Randolph Nesse interviews for a basic understanding of evolutionary medicine

http://www-personal.umich.edu/~nesse/Articles/Nesse-Stearns-GreatOppty-EvolAppl-2008.pdf