Do multiple vaccines overload the immune system? Apparently not.

One common claim of the anti-vaccine movement is that there are just too many vaccines these days, and that the sheer number given is overwhelming the immune systems of many children and leading to all sorts of potential ills specified or unspecified (autism is a biggie here, but there are others attributed as well).  Hence, the whole theory of 'selective vaccination', where you pick particular ones to give your children and leave the rest. 

I never found this theory terribly convincing.  After all, we're swimming in germs all the time – the vaccines we get are a tiny fraction of the bacteria and viruses that our immune systems have to deal with on a day-to-day basis, even before you take into account the fact that the germs in vaccines have been deliberately weakened or even killed off before being administered to people.  It always seemed to me like plain common sense that our immune systems wouldn't find it that much of a big deal to handle several vaccines at a time.  However, I never had anything more concrete than that to counter the claims about overloading of the immune system.

Then, I read Paul Offit's "Autism's False Prophets".  This is the book I have been hoping for years that somebody would write; a clear and simple account by a paediatric microbiologist of the whole story of the vaccine/autism controversy, giving the true stories behind the many frightening and plausible-sounding claims made by the anti-vaccine campaigners and explaining why the evidence does not support them.  The debunking of conspiracy claims was marvellously welcome; the scientific parts of it, of course, I already knew quite a bit about because of having access to medical journals. But I learned one particular piece of information that I actually hadn't known and that sounded so simple and obvious once it was explained that I still can't believe it isn't publicised far more by the pro-vaccine side of the argument; the scientific reason why the 'overloading the immune system' theory doesn't stand up.  I share it with you here in honour of National Vaccines Week.

You see, although we think of vaccines in terms of how many germs are vaccinated against (and thus it looks to us as though the list is getting longer and longer; and, while I don't see that as a problem for the reason given above, I can appreciate that to a lot of parents it does look daunting), that isn't how it works on the level of the immune system.  The immune system 'sees' things in terms of how many proteins it has to mount an antibody response to.  And this is not a simple one-to-one relationship; in fact, every germ that the immune system mounts defences against has multiple surface proteins against which antibodies need to be made.  The number of proteins involved (they're called antigens, by the way, if you want the technical term) depends partly on the size of the virus or bacterium being fought against; in the case of vaccines, I believe it also depends partly on the technique used to render the germ in question unable to cause full-blown infection so that it can be safely injected into the human body.  (When Offit made this point, I did in fact remember something I'd seen mentioned in passing during the huge controversy over the five-in-one vaccine that was brought in a few years ago; that it actually contained fewer of these proteins than the separate vaccines had, and was thus, if anything, going to present less of a challenge to the immune system than the vaccines given prior to that.)

Anyway, about a hundred years ago or thereabouts, the only vaccine children received was the smallpox vaccine; now, of course, they receive far more than that.  But, according to Offit, the number of foreign proteins presented to a child's immune system by the total vaccination schedule currently recommended for children in the United States today is actually substantially less than the number of foreign proteins that were contained in the smallpox vaccine alone.  (Here in the UK, of course, it will presumably be even fewer, as there are a couple of vaccines on the US schedule that we don't have on ours.)  The smallpox vaccine (which is no longer given) contained a grand total of 200 foreign proteins for the immune system to deal with in one go; the vaccines advised for a child in the US today contain a somewhat more petite total of 153 foreign proteins.  So, if overloading of children's immune systems from vaccines actually was the cause of autism or of whatever disease the anti-vaccine lobby happen to be currently claiming, we'd expect to see the rate of the disease in question dropping rather than rising. 

The logical conclusion?  No, the current vaccine schedule is not causing any sort of overload of children's immune systems.  Children's immune systems, in fact, have noticeably less to deal with than they did a hundred years ago.  153 proteins?  Luxury.

Edited to add: I've now submitted this post to a cool blogging mini-carnival that I recently stumbled across, going by the name of Controversunday.  If I do this properly, a badge should now appear that you can click on to lead you back to the host blog and thence the other submissions, and if I don't do it properly, you'll get a load of gobbledegook.


(Woo-HOO! It worked! I am the GREATEST! Ahem.)


Filed under Sacred hamburger

11 responses to “Do multiple vaccines overload the immune system? Apparently not.

  1. Well done. I’m wondering when the anti-vaxers will come out of the woodwork to comment on this blgpost.
    Off to watch the Frontline documentary!

  2. Granny C

    Out of interest what vaccinations are required in the USA that are not part of the programme here in the UK and what is your view on this? What a useful Mum you are! Love Granny C

  3. Thanks!
    I know the US does Hep B and I think chicken pox – not sure of the others offhand.

  4. Christine

    Others immunisations included in the routine schedule in some parts of the USA are rotavirus and Hep A, some other countries include yellow fever and Japanese encephalitis as part of their immunisation schedules.

  5. This makes so much sense! The problem is that laypeople think in terms of the “big” numbers (1 or 2 shots versus 4 or 5) and not the particulars of what that actually means (so, 200 vs. 153 proteins). We’re in the US and follow the recommended vaccine schedule, which is:
    2 months: DTaP/Polio/Hepatitis B, Prevnar, Hib (Type B Flu), Rotovirus
    4 months: the same
    6 months: the same, plus a seasonal flu vaccine (four shots all together)
    1 year: Prevnar, Hep A, Hib
    I don’t know exactly how that differs from the UK but would be interested to know.

  6. Oh, thanks! That’s interesting – you have some that we don’t but don’t have the Meningitis C, which we do, and space your first few out more.
    Ours is (I had to check this because it’s changed in the past few years and is so complicated nowadays…):
    2 months: The 5-in-1, which is DTaP/polio/HiB, plus pneumococcus (this will either be the Prevnar or the equivalent – I can’t remember which brand we have).
    3 months: The 5-in-1 plus Meningitis C
    4 months: All of the above – the 5-in-1 plus pneumococcus plus Meningitis C.
    12 months: Boosters for HiB and Men C
    13 months: MMR plus booster for pneumococcus
    Then a whole bunch of boosters again at three and a half, then more at 16, plus the Gardasil vaccine somewhere in between for girls (yup, given up on even trying to keep track of the schedule).

  7. Christine

    The conjugate pneumococcal vaccine we currently use in UK is Prevenar13, the UK brand name for Prevnar. The human papilloma virus (cervical cancer) vaccine given to school girls routinely is Cervarix, this is offered to year 8 girls, 12-13 yrs,and is currently being offered to all secondary school girls who have not already received it. Gardasil was not chosen by the Department of Health for the routine schedule. I’m a practice nurse and spend quite a lot of my time working out what imms to give to children who’ve moved into the UK, having started imms in their country of origin. It can be more than a bit complicated!

  8. (thumps head) Sorry, Cervarix. Bah. All that time everybody spent arguing over which to use should really have cemented the final decision in my brain, shouldn’t it? Obviously had the opposite effect.

  9. Christine

    I only remember really ‘cos it’s a permanent fixture in our vaccine fridge at work now, but we do occasionally give Gardasil to girls whose parents are under the impression it’s the better vaccine and request it forcefully enough! Shame the schedules aren’t the same, I have to look up Gardasil every time. Good old Green Book online!

  10. For me, it is the worry of the other things in vaccines that gets me, not the viruses themselves. I figure it isn’t worth the risk of extra chemicals for a child/person whose body is equipped enough to handle the flu without getting a vac first. I’ve read a lot on other vaccines though (Hep B, etc) and how people are assuming they are unnecessary because the herd immunity keeps the unvaxed kids safe.
    I always heard it was mercury or aluminum or something people worried about causing autism. Personally I think it’s far more likely certain problems are popping up because we are surrounded my so many more chemicals – our society is a lot more obsessed with cleaning products, people are drinking only bottled water, etc etc.

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