Question from BL Facebook pg about vaccination & evolution

(Christy Hemphill) #1

Occasionally people send questions to the BioLogos page inbox that would be better addressed by a group. Any input, folks?

Lori asks:

With all the hoopla concerning whether to vaccinate or not, are there any resources you may have on this?

Not having grown up learning about evolution, (young earth Christian school) I’m probably asking a dumb question, but would enough people not vaccinating have an effect on the evolutionary process?

I’m looking for resources and facts more than a debate.

(Stephen Matheson) #2

It’s not a dumb question. The answer is that yes, in principle, the evolutionary process is affected by vaccination, just as it is affected by sanitation (clean water), antibiotics, C-sections, and essentially every medical intervention. In the absence of such things, people who regularly survive childhood today would instead die as children before reproducing. This can (and probably does) involve natural selection, in that some people are naturally resistant to the scourge or are otherwise unsusceptible to the particular risk. Whether current outbreaks of disease among unvaccinated populations are enough to discernibly affect the gene pool in future generations (which is what evolution is), I don’t know.

(Christy Hemphill) #3

Maybe this is not what Lisa was asking, but I’m curious about the effect on the microbe population more than the human population. If you have a large population of unvaccinated people like we are seeing with the recent measles outbreaks, how does that affect the evolution of the microbe, in terms of the emergence of vaccine resistant strains that can then make vaccinated people sick?

(Stephen Matheson) #4

Ah. Interesting question too! Not my area of expertise, since this is a question about population dynamics. But I think the answer would go something like this. In a vaccinated population, the pathogen population must consist almost entirely of resistant strains, assuming there is no other reservoir (i.e. place to hide) such as another host species. (And assuming the pathogen hasn’t gone extinct, which can happen, cf. smallpox.) The unvaccinated population offers a nice reservoir in which to reproduce and generate more variants, and it represents new opportunities for those variants to spread. From an evolutionary standpoint, that’s really all the unvaccinated population has to offer the pathogen, but maybe that can create evolutionary opportunities that wouldn’t exist in a vaccinated population. I can’t think of any other clear evolutionary implications, but I could be missing something, and it could be that just the additional reservoirs and opportunities can be significant from that evolutionary perspective.

(Phil) #5

Good questions. I am not aware of most diseases we immunize against developing vaccine resistant strains with the notable exception of influenza, which varies a lot in nature and mutates frequently, and different strains pass through the population unpredictably.
The effect on others would probably be variable. Tetanus has a huge soil reservoir, so human infection or immunization has no real effect on the population.

(Jay Johnson) #6

Hoopla? There’s a hoopla about whether to vaccinate? What else am I missing? Is there a hoopla concerning whether to wash one’s hands or brush one’s teeth?

(Christy Hemphill) #7

The Russian bots have not taken up the cause of the anti-hygiene movement yet.

(Stephen Matheson) #8


(Steve Schaffner) #9

It does happen with other viruses – Hep A, Hep B – and bacteria. I suspect there’s been some loss in efficacy of the the mumps vaccine, although there’s no hard evidence.

(Laura) #10

That’ll probably be next. :wink: I imagine the “hoopla” sounds a lot louder to those of us who currently have small children of that age, and also friends at similar stages.

(Phil) #11

Interesting stuff, still fairly rare so far not a huge clinical problem. Main problem is the waning immunity with age with most vaccines. That too can be a problem. Only case of measles I have seen in practice was a 24 year old EMS worker before they started recommending a booster MMR. On the other hand, have seen several kids die of meningitis and epiglottiis in the early years, things that are rare now with the decrease in invasive H. flu since the Hib vaccine developed.

(Stephen Matheson) #12

Har! Hoopla or not, I have noticed that my kids are all obnoxious, and all have been vaccinated, and none could possibly have acquired this trait genetically. Word to the wise.

(Albert Leo) #13

Before one dismisses a movement, such as anti-vaccination, as just a bunch of misinformed kooks, it makes sense to make as certain as possible that there is NO obscure factual basis for it. Amongst my relatives there is a family that appears to have a genetic tendency for nervous tics (eye twitch in this case). In the youngest girl this showed up soon after birth, but until she was almost two, her motor and mental development seemed normal. (beginning to walk and talk) Just days after receiving the usual DPT combined vaccination she regressed markedly–barely able to crawl, and no longer making attempts of speaking in sentences. Coincidence, perhaps. The internet sheds some light on the question: “The relationship between DTP vaccine and neurologic illness lacks specificity. Case series have had an impact on both physicians’ and the lay public’s impression of the safety of pertussis vaccine greatly out of proportion to their scientific importance.”

My question is this: Do physicians make a careful examination of the patient’s neural health before giving the OK for vaccination? If there is even less than one chance in ten thousand that the pertussis vaccine can adversely affect a child who has an as-yet undiagnosed nervous system problem, it would be worth the effort to make an exception for him/her.

So dismissing the anti-vaccinators position (comparing it to refusing to wash hands and brush teeth) seems both unfair and unscientific to me.
Al Leo

(Phil) #14

No doubt there are some vaccine related complications. However, they are rare, and in that particular case, it would be interesting is there could be shown a correlation with her immune response and some autoimmune disease stimulated by the vaccine. There are some unusual syndromes that occur, and are also complications of natural disease. PANDAS is one associated with streptococcus. On the other hand, predicting who will respond adversely is not that successful as these are rare and episodic. I doubt a family hx of tics would raise any red flags. I saw one study that associated mercury in vaccines with Tourette’s syndrome, but childhood vaccines have had no mercury in them since 2001.

(Jay Johnson) #15

Yes, it was unfair of me. I was mostly expressing surprise that it was even a “thing,” since I’m not on Facebook or any other social media. Sorry if I gave offense. Did the little girl develop normally, other than the tics?

On the science, I’m officially getting out front of the no-hygiene hoopla. According to an article in Science Daily, “childhood leukemia, type I diabetes, other autoimmune diseases, and allergies are preventable if a child’s immune system is properly ‘primed’ in the first year of life.” As part of this “priming,” adults must not insulate children from infection, and therefore parents should not wash themselves nor their infants during the child’s first year – or two, to be safe – of life.***

*** WARNING: The above paragraph is an example of pseudoscience produced by quote mining. Couldn’t help myself.

(Laura) #16

Dang it, I was all excited for a minute there… I thought I could forgo showers for a couple years and just claim I was doing it for my kids. :smiley:

(Mervin Bitikofer) #17

I’m right there with you, Jay! I think I’ll forgo my daily bathing ritual today so that I too can be ahead of the curve on this. My wife may get on here in the next day or two to thank you for getting me the heads-up on this! :no_entry_sign: :soap: :no_entry_sign:

(Randy) #18

How about raw water? I think someone must have mentioned this once on this discourse, somewhere…

(Christy Hemphill) #19

This article was top on the NPR homepage this morning. It doesn’t address evolution, but it does have some interesting global stats and explains why measles epidemics are an indicator of low vaccination rates. It’s crazy to think that we were on the path to making measles extinct like smallpox, but not so much anymore.

(Phil) #20

A hot topic on one of my medical forums concerns how pediatricians handle it. A lot of pedi practices will not treat anti-vax folks because it exposes susceptible infants to illness in the waiting rooms etc., and it forces them to practice sub-standard medicine and opens them up to legal liability.
It will be interesting to see how it all plays out.