Evolution and vaccinations

iVillage Member
Registered: 04-08-2003
Evolution and vaccinations
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Tue, 09-02-2003 - 2:08pm
A friend brought up his thoery to me that I found interesting. He said that he thinks we are maybe stalling human evolution by vaccinating. It used to be survival of the fittest and now it isn't. I am not saying I agree with him, but I found his arguement interesting. He has no scientific research or anything to back it up, it was just his personal theory. What do you think?

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Avatar for catherina
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Registered: 03-27-2003
Tue, 09-02-2003 - 4:40pm
Interesting thought - I know I stalled evolution by having DD by C-section. I would have taken DD and me out of the gene pool otherwise ;0)

The question of VPDs and "weeding out the weak" has been addressed by Peter Aaby in this publication:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11738762&dopt=Abstract

Vaccine. 2001 Dec 12;20(5-6):949-53.



The frailty hypothesis revisited: mainly weak children die of measles.

Aaby P, Whittle H, Cisse B, Samb B, Jensen H, Simondon F.

Projecto de Saude de Bandim, Bissau, Guinea-Bissau.

It has been suggested that measles infection mainly kills frail children who are likely to die anyhow of other infections. If that were true, the proportion of frail children should increase after the introduction of measles vaccination and post-measles mortality compared with mortality in uninfected children should increase when the case fatality declines and frail children are no longer dying of measles. The latter deduction was investigated in Niakhar, Senegal, where the measles case fatality has declined markedly. Measles has been studied in Niakhar during 12 years from 1983 to 1994. We compared long-term mortality after measles infection in periods with both high and low case fatality. The acute measles case fatality rate (CFR) declined from 6.5% in 1983-1986 to 1.5% in 1987-1994, an age-adjusted decline of 66% (RR=0.34 (0.19-0.58)). Between 1983-1986 and 1987-1994, mortality in the first year after measles infection declined by 35% (RR=0.65 (0.37-1.16)), the pattern being the same in the second and third year after infection (RR=0.63 (0.33-1.21)). This reduction could not be related to introduction of immunization, treatment of measles with Vitamin A, or prophylactic use of antibiotics. Controlling for age, immunization, and season, the decline in post-measles mortality was similar to the fall in non-measles-related mortality between the two periods (mortality rate ratio=0.72 (0.64-0.80)). Since the mortality decline in survivors of measles was as large as the decline in mortality among uninfected children, reduction in acute measles mortality did not lead to accumulation of frail children. We doubt measles infection ever eliminated mainly weak children; it always killed a broad spectrum of children, most of whom were "fit to survive". Hence, it seems unlikely that measles vaccination has contributed to the survival of more frail children.

Food for thought

Catherina

Avatar for kidoctr
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Registered: 03-25-2003
Tue, 09-02-2003 - 10:44pm
Interesting theory that likely comes from someone who considers himself to be one of the "fit". It moved far, far away from "survival of the fittest" well before vaccines came into the picture and I find nothing wrong with that at all. I, for one, am glad that the "survival of the fittest" mentality has gone by the wayside - it's ridiculous to assume that those with (or destined to have) life threatening conditions are not worthy of intervention. My family would also not be around had it been deemed "ok" to allow children with pyloric stenosis to simply waste away and die. Maybe the way to look at it would be to see human evolution actually being "speeded up" by all the people who would never have lived to do great things. Maybe by saving an extremely premature infant we would see that infant go on to make the greatest medical breakthrough in history someday(greater than vaccines, lol - kidding - sorta). If we consider vaccines to be an impedement to human evolution, there's no reason to not consider any other medical intervention to do the same. I don't think that the case, though.

Eve

 
 
iVillage Member
Registered: 03-27-2003
Wed, 09-03-2003 - 2:34pm
I have heard this theory articulated wrt our modern way of life in general, and while I would not adopt the radical position that we should "allow the so-called weak to persih", the point is quite valid, all ethical considerations aside.

WRT vaccination/suppression of acute illnesses in the mass popululous, there is ample scientific data to back up the theory that widespread experience with infectious agents "immunizes" a population against future mortality, whereas mass vaccination is less reliable in this respect, esp. on a genetic level (multigenerationally).

Coincidentally, I just saw a very interesting program on this very subject last night; looking at the "Black Death" of the middle ages and the genetic charateristics of those who survived infection/death. Turns out there was a genetic mutation involved, which was passed on to the decendents of the survivors, rendering them immune to infection or death, depending on whether they carried one or two copies of the gene.

Further turns out that this very same gene is also protective against HIV infection.

Now, had mass vaccination existed against the "black death" (bubonic and pnemonic plague), this mutation would either not have arisen or would have been diluted out of existance over time. By any accounts, far fewer would carry it, and far more would currently be vulnerable to these two illnesses, with what consequences??

Of course, we would just have to continue mass vaccination forever, but as the number of pathogens and the vaccines for them increases, that becomes an increasingly untenable prospect, with increasingly relevant risks.

Other recent research has discovered that chimps, many of whom prove immune to HIV infection and/or illness, carry genetic clues to a massive epidemic which desimated their population many thousands of years ago, leaving mostly the immune to reproduce. In such ways do species "erradicate" pathogens as a source of grave morbidity and mortality, and it is this process we are subverting. Are we, in some cases, reversing the gains made against certain pathogens by our antecedents by rendering moot this process of selection? Perhaps.

What about all the once common childhood illnesses we now mass vaccinate for? We have engineered a population that has no natural immunity to these pathogens, is permanently dependent upon their suppression, and which does not select for resitance/survival.

And of course, we also artificially protect many who would perish from other causes/genetic and other weaknesses who would otherwise not have survived to reproduce, with definate impacts on the future genetic and other characteristics of our population.

As I said, as humans, we muct also consider the ethical ramifications involved, but as far as science and nature goes, there is little question that we are subverting the proven process. The ultimate results remain to be seen. It may turn out that we condemn more to death in the future than we save in the present. A complicated and controversial issue.

Kimberly

Avatar for keeley_14383
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Registered: 03-27-2003
Wed, 09-03-2003 - 8:58pm
Wasn't that a fascinating show?! I posted about it some time ago after I saw it (didn't catch it this time around.) I was struck by the fact that genetics CAN be so important regarding infectious disease. I had no idea -- I assumed enviromental factors were much more important. It was disconcerting to realize that although undoubtedly there are factors you can influence (such as good diet, adequate rest, etc), whether or not you contract a disease can be so clearly out of your control (assuming you are not a hermit and so never risking exposure, LOL).

It is fascinating that HIV virus cannot infect those people with two copies of the mutated gene. Also curious (and very unfortunate) that the mutation is seldom seen in Africa.

I had to respond to this paragraph of yours: "Other recent research has discovered that chimps, many of whom prove immune to HIV infection and/or illness, carry genetic clues to a massive epidemic which desimated their population many thousands of years ago, leaving mostly the immune to reproduce. In such ways do species "erradicate" pathogens as a source of grave morbidity and mortality, and it is this process we are subverting." (*****here's me again ****)This could well be true -- but who is to say it is better to allow our population to be *desimated* rather than try to create vaccines to avoid this type of tragedy? Mother Nature's ways might get the job done, but she sure is tough. I don't believe you meant to say it is GOOD for massive epidemics to occur and kill many people, but this argument would lead to the conclusion that it is necessary to allow epidemics to weed out the weak. We either try to prevent them, or we suffer through and allow the "strong" to continue reproducing. Of course, a big hole in this argument is that there is no guarantee those who are "strong" enough or genetically gifted enough to survive this particular epidemic have genes that are especially worthy of continuing when considering other important qualities. Or even genes that are especially resistant to other infections. (Ugh, re-reading those two sentences just gave me nasty chills, imagining gene research leading to engineering babies to resist infection and for other desired traits -- But now I'm getting *completely* OT! Let's not go there.)

Ethically, we have to do what we can to save lives, as best we know how at the point in time. The results of which certainly might make our species "weaker." (As a side note, add me to the group of weaklings who would not exist without modern medicine -- I would have died at age 4 from an anaphylactic reaction. Of course, my mother would have died at age 2, so I could go on and on here!! I am surely not fit to breed by the standards some would use.)

I would add another point, however. I believe the most valuable resource in the world is the human mind. By saving these lives, we may well be saving the mind that will make a major breakthrough in how we treat/prevent disease. Hmmm...seems like you can make a half-empty argument or a half-full argument, it's all in the current perspective! As you said, it certainly is an all-around complicated and controversial (and, I'll add, fascinating)issue.

Keeley

Avatar for joolsplus2
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Registered: 03-27-2003
Thu, 09-04-2003 - 7:47pm
Think back to when explorers and settlers spread disease to Native Americans (and other native peoples...Hawaiians, Australian Aboriginals, New Zealand Maoris...and all the others of course). Imagine if they had brought smallpox vaccines with them (and other diseases, but this was a biggie)....Imagine how much culture wouldn't have died off with those native peoples! And how much knowledge of the land, and OTHER ways that made people FIT for their environment.

Yes, it's probably valid to argue that vaccines are making us somewhat less fit to survive in some environments, but by the same token, one would have to argue that we shouldn't use sunscreen, and that those of us who aren't FIT to live in sunny climes, should just die of skin cancer, or that we should not fortify milk with vitamin D in colder, darker regions, and those with dark skin who can't make as much vitamin D as they need for strong bones should just die from rickets...and there are SO many examples of people not being truly fit for survival, but that we have been able to take care of.

Really, it's not possible to judge what great threat will face us all tomorrow, and genetics is important, but it isn't everything. For instance, the number one cause of death in this country for people ages 1-34 is auto crashes...should we give up on passenger safety measures like seatbelts and carseats, so that only the people with genetic traits that allow them to withstand massive G-forces and impacts be the ones allowed to survive?

Just thinking too much,

Julie

Julie

9 out of 10 carseats are installed wrong.  Could yours be?

iVillage Member
Registered: 03-27-2003
Sat, 09-06-2003 - 2:57pm
Julie, I wouldn't worry about "thinking too much"; most think too LITTLE, lol!

One thing about the introduction of pathogens to indigenous populations that has to be mentioned is that, more often than not, other factors were introduced at the same time. Refined sugar, alcohol, coffee, refined flours, changes in housing (rel. airtight structures as oppsed to well ventilated structures), not to mention general trends of cultural and literal genocide with the displacemnt and other stress that goes along with it. Not to dismiss the effects of lack of experience with a particular pathgen entirely, but many other factors at play to consider as well.

Re' sunscreen, studies have found that those who wear the most sunscreen have the highest skin cancer rates. One explaination is that those who tend to wear the most protection live where it is most needed and have a resulting greater risk, and/or that they have a false sense of security which causes them to over-expose themselves.

Another hypothesis is that the use of sunscreens weaken the natural resistance to sun exposure by short-curcuiting the production of vitamin D (which is tied up with calcium and magnesium utilization, blood-circulating calcium being protective of the skin) and by preventing the production of melatonin, which serves to protect the skin as well.

As for vit. D (actually a hormone) there are, geographically, very few who cannot produce enough even in winter through 15-30 min. of exposure to sunlight. Those who sometimes cannot, such as the Eskimos, have traditionally also been forced into diets containing animal stores of the hormone. I think most of the deficiencies we see reported recently are the result of over-cautiousness of/lack of exposure to the sun, and could be safely remedied by increasing exposure moderately. One needn't spend hours (or any time at all) in the noonday sun, (DUH! Maddogs and Englishmen, as they say;), to get the required 15-30 minutes on the forearms; a half hour of 10 am or 5 pm walking outside will usually do it.

The auto fatality/seatbelt analogy is an odd one, considering that we were never "designed" to go hurtling through space at 70 mph in metal boxes anyway, LOL! The whole process consitutes a serious modification in itself.

Kimberly





Avatar for kidoctr
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Registered: 03-25-2003
Sun, 09-07-2003 - 11:47pm
>"What about all the once common childhood illnesses we now mass vaccinate for? We have engineered a population that has no natural immunity to these pathogens, is permanently dependent upon their suppression, and which does not select for resitance/survival."<<

Doesn't it? What about selecting for those able to "withstand" vaccination and produce immunity and, eventually the "bonus", eradicating these diseases? Oops, that's not what mother nature "intended" so we shouldn't do it?

>>"As I said, as humans, we muct also consider the ethical ramifications involved, but as far as science and nature goes, there is little question that we are subverting the proven process"<<

The "proven process"? Um, one of these proven processes is the "natural selection" of those with sickle cell anemia trait that protects against malaria infection but with the big OOPS problem of an autosomal recessive disease that results in excruciatingly painful crises. What makes it a "proven" process? The fact that you're alive to proclaim it as one? Hm, I would tend to disagree. I think nature is far, far from perfect.

>>"The auto fatality/seatbelt analogy is an odd one, considering that we were never "designed" to go hurtling through space at 70 mph in metal boxes anyway, LOL! The whole process consitutes a serious modification in itself."<<

As though we were "designed" to withstand nature's volcanic, earthquake, hurricane, tsunami, tornado, etc, etc, etc activities? LOL!

Eve

 
 
Avatar for joolsplus2
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Registered: 03-27-2003
Mon, 09-08-2003 - 1:11pm
How about we look at it from a different perspective...the germ's perspective. Why do THEY get to evolve as they wish and WE just have to lie back and take it, because we happen to be or not be genetically immune?

I highly recommend the book "Guns, Germs, and Steel: The Fates of Human Societies" by Jared Diamond...in which I learned that smallpox spread throughout the Americas even before settlers worked their way inland...so you really can't blame the crummy diet being brought by 16th century explorers as leading to the downfall of health in these societies due to introduced germs. Instead, it shows how populace, sedentary societies (ie, NOT small bands of hunter-gatherers) allowed these nasty germs to flourish in the first place, by living in close quarters with farm animals, having poor or no sewage systems, and plain old living next to lots and lots of other people. We have cleaner living now, but still have lots of contact with other people, so if most of us weren't vaccinated, we'd still be seeing lots of VPD's making lots of people sick.

As for car crashes...just because it's hard to imagine what we'd look like if we were "immune" to those (because, say, someone with a genetic mutation for a REALLY strong skull mangaged to have more offspring than those of us with skulls as we know them, for instance), doesn't mean it couldn't eventually happen.

http://www.amazon.com/exec/obidos/tg/detail/-/0393317552/ref=lib_rd_btb/102-5829413-8760146?v=glance&s=books













Julie

9 out of 10 carseats are installed wrong.  Could yours be?

Avatar for kidoctr
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Registered: 03-25-2003
Mon, 09-08-2003 - 2:54pm
Julie - I agree with you. Why should germs be the ones allowed to run rampant at the expense of human lives? Who made mother nature the "boss"? The idea of "survival of the fittest" is terribly antiquated. That book sounds interesting... I just finished reading "The Physician" by Noah Gordon - a gift from my sister. Took me a LONG time to finish the 700+ pages. LOL. Now on to the rest of my reading list...

Eve

 
 
iVillage Member
Registered: 03-27-2003
Sat, 09-13-2003 - 1:40pm
Well, FTR, it's not 'my theory', or one I even necessarily ascribe to in all (or even most) aspects. Someone raised it and I responded with some comments and speculations. So I do not feel terribly compelled to defend it.

I will say that we have a very limited understanding of "mother nature" (who was "made boss" long before WE came on the scene, and is, in a very real sense, STILL "boss", despite our attempts to make an employee of "her".)

That does not mean we should not try to improve things, but I pers. conclude that trying to do so by treating nature as an enemy, rather than by working with nature, is counterproductive. JMHO. Nature is not some personified being out to get us, but a logical force which strives for equilibrium in all things, like gravity or magnetism, imo. Once you understand such a force, you can devise ways to work with it/make it work for you, but you can never supercede it entirely, or avoid the consequences of trying to do so.

Who are we, at this stage of our development, to judge that "germs are running rampant"? We do not even fully understand the functioning of our own immune systems, for heaven's sake, much less say the multitude of interactions or organisms involved at the microscopic level. We have come far enough to realize that most microorganisms are beneficial, or even a requirement of our existance. We learn more all the time through trial and error. It is this that I, as a parent, have to concern myself with, given the very recent emergence of mass vaccination in general and specific vaccines in particular. Trial and error is not a sound enough basis upon which for me to base decisions re' my children on, JMHO.

Kimberly

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