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Why vaccines *won’t* overwhelm your immune system

A very quick post today, but a topical one given the situation in Wales (and the UK in general) with regards to measles.  The latest press release from the Welsh NHS has said that there are now 765 known cases, and that over 70 of these people have been hospitalised.  That’s one in ten of the people affected who have ended up in hospital.

There has been (entirely reasonable) supposition in the press that the people affected are largely children who were not vaccinated with the MMR due to the completely false suggestion that the vaccine may cause autism or bowel disorders.  It is felt in some circles that the vaccine may somehow overwhelm a child’s immune system, and lead to illness.

Numerous studies have disproven ths link, and the original paper that suggested it has been withdrawn by the publisher.  The paper itself has been called not only wrong, but downright fraudulent.  Sadly this hasn’t been enough to undo the damage done by the original paper, and by the subsequent media storm that erupted around it.  Measles is not a trivial infection, and as the Welsh NHS press release rightly says, “it is just a matter of time before a child is left with serious and permanent complications such as eye disorders, deafness or brain damage, or dies.”

So in light of all that, I stumbled across this quote this morning in an article published at Medscape.  It’s a rather eloquent way of highlighting the scale of immune assault that we all face every single day, and how unlikely it is that any vaccine could pose a risk on these grounds:

In general, however, if you take a step back and look at this question, the notion that the number of immunologic components in vaccines could in some way weaken, overwhelm, or perturb the immune system is fanciful. When we are in the womb, we are in a sterile environment. When we leave the womb and enter the birth canal and the world very quickly, we are colonized with trillions of bacteria, to which we make an immune response. The total number of immunologic components in today’s vaccines is approximately 165. When you think about the number of antigens that you encounter (remembering that a single bacterium has 2000-6000 immunologic components) and that you are making grams of immunoglobulin every day, that the dust you inhale isn’t sterile, and the food and water that you eat and drink aren’t sterile…The notion that vaccines would somehow weaken or overwhelm the immune system is certainly not supported by what we know about immunology and microbiology.

To put it another way, one single bacterium has 12-36 times as many immunologic components as the average vaccine.  The average person has trillions of bacteria on and in their bodies (in fact in terms of cell numbers we’re more bacteria than we are human), so the addition of a few extra antigens in a vaccine is really a vanishingly tiny drop in a huge ocean.

While I’m not trying suggest that vaccines are risk-free (because that can’t be said of any medicine), the risk of being vaccinated is certainly much lower than the risk of complications from catching something like measles.

Postscript: Medscape have a second article about a recent study that found no link between childhood vaccination and autism; it’s worth a look if you have a login.

EDIT: thanks to Nico in the comments for pointing out a factual error.  I originally asserted that by weight a human being is more bacteria than human.  That is of course wrong (we’re 1-3% bacteria by weight).  We do however contain 10 times as many bacterial cells as our own cells.  Which is either quite wonderful or rather creepy, depending on how you look at it.


Should you believe the fitness hype?

I see this over and over again among otherwise very intelligent people; an odd belief that the latest “big” thing in exercise or weight loss will be a magic bullet that suddenly brings them the body they’ve always thought they should have. Zaggora hot pants (Burn more calories!), Skechers Shape Ups (reduce cellulite!), green coffee extract (100% natural!) – the list is basically endless. Leaving aside the notion that this will somehow make them happy (for I haven’t the knowledge or skills to even begin to tackle that), why do these bright people fall for it?  I can’t answer that either. It’s potentially very harmful though – this tweet from @nchawkes says it rather well:

People end up spending frightening amounts of time, money and energy on these promises, and even when there’s temporary success (often due to diving into a new regime with a positive opinion, in my totally-un-evidence-based opinion) ultimately there’s stagnation at best, failure or regression at worst. These things are hugely destructive to body image and overall self-image.

So if I can’t explain the fascination with these things, the least I can do is provide a small extra weapon in the battle against profiteering and misinformation in the fitness world.  (Aside: it’s worth noting that much of the misinformation is spread amongst well-meaning friends, just trying to help one another; this type is just as difficult to address as any other dearly-held belief).

My first pearl of wisdom is hardly novel: anything that seems too good to be true, is. The cold hard truth is that you can’t permanently change your body without permanently changing your diet and lifestyle; they needn’t be massive, life-altering changes, but they must happen. You also can’t permanently change your body by throwing money at it instead of good quality food and exercise (unless we’re talking surgery; that’s pretty permanent).

My second piece of advice is: apply critical thinking. Is there something you’re naturally skeptical about, or distrustful of? Apply that same level of suspicion to diet and lifestyle advice. New device guarantees weight loss in one workout? Great. What’s the mechanism? Does it seem plausible? Is it more likely that it’s just helping dehydrate slightly, thereby losing water via sweat? Never ever forget that water’s heavy; 1kg (2.2lb) per litre to be precise. Doubt everything. 

Thirdly, and maybe most importantly (and predictably), demand evidence. Good quality evidence at that. Be ruthless. Be picky. Crucially, don’t accept anecdotes. These are everywhere in weight loss fads, to the point that I feel they’re worthy of a specially-adapted version of the anecdote rules:

  • Did the person gain the advertised benefit, and maintain it?
  • Was the advocated treatment the only one used?
  • If it’s really so good, why aren’t doctors and fitness professionals everywhere advocating it?

I’m hoping to look at some individual claims in more detail, but hopefully this post will at least serve as a cue to get you thinking about the way you look at claims in the weight-loss industry.