Vaccines and autism – an update

Vaccines and autism: the history and an update[1]

Note: Readers might also want to check out my later post on the “autism epidemic“.

In 1998, a doctor in England named Andrew Wakefield[2] (in conjunction with other physicians) published a paper which suggested a link between the MMR (measles-mumps-rubella) vaccine and the development of autism.[3]

Understandably, this raised an enormous amount of concern. Vaccine rates dropped. Parents today remain worried about this.[4]

As it turned out, Wakefield had falsified patient information, distorted data, and did not disclose that he was being paid by lawyers that wished to sue vaccine companies. Eventually, the medical journal took the almost unprecedented step of retracting the paper, and all his other co-authors disclaimed the study. Wakefield lost his medical license for his role in the fraud.[5]

The damage, however, was done. Parents continue to worry that “vaccines cause autism,” or some variant. Even though the only evidence of this was faked and cherry-picked data, people continue to worry.

It is understandable that parents whose children face a difficult illness (I have two nephews with the condition, so I understand the difficulty and some of the worry and pain) would seek for a reason. And, since parents and medical personnel often begin to notice the behavioral difficulties that accompany autism around 12-18 months (the time of the MMR vaccine), it is easy to see how parents might see a link where there truly isn’t one.

But, no one is well-served if we adopt false ideas about the cause of autism, especially when parents opt not to vaccine for deadly diseases—they put themselves and my children at risk.

No vaccine is 100% effective, but if enough people are vaccinated, the rest are protected by what we call ‘herd immunity.’ Babies too young to be vaccinated are likewise protected. So, a decision of someone to not vaccinate does not just affect their child, it affects my child and your child.

We know very well  what happens when vaccine rates drop—the diseases against which they protect us come roaring back. (This happened in the UK and Japan with the MMR scare, and in the former USSR when their vaccine practices lapsed with the fall of Communism. One can’t say much for Communism, but it was at least good at getting everyone lined up for their diphtheria vaccination.)

The Evidence

Three major theories have been offered by those who claim that vaccines are a cause of autism. (A big proponent of these has been former Playboy model Jenny McCarthy on the Oprah Winfrey show—though what qualifications Ms. McCarthy has to make declarations about such matters is not clear. I somehow don’t think that Hugh Hefner is running microbiological seminars at the Playboy Mansion.)

#1) MMR link — as noted, this was due to Wakefield’s fraud. Since then, twelve studies have been done looking for a link, and none has been found. It is impossible to prove a negative in science, but this is pretty good evidence.

#2) Thimerosol — the second claim is that a preservative put in some vaccines (thimerosol) caused the problems. Thimerosol contains mercury, and so it was easy for those who didn’t know much biochemistry or who wanted to spread fear to claim it was a poison or toxin. (In fact, we now know that this form of mercury is much less toxic than others; it was removed from vaccines anyway as a precautionary measure, though there is no evidence that it causes any known human problems at those doses.)[6]

But, even though the claim doesn’t make much theoretical sense, seven studies have failed to find an association between thimerosol exposure and autism. Furthermore, thimerosol is not used in the vast majority of childhood vaccines anymore (the annual flu vax still uses it), and yet autism rates have not altered downward at all—they’ve continued to climb. So, this theory hasn’t panned out either.

#3) Too many vaccines?

This has been the hardest claim to answer. The worry is/was that because more vaccines are now given to children, this has somehow “overwhelmed” their immune system.

On its face, the claim makes very little sense. Children are exposed to thousands of different types of viruses, bacteria, and other stimulants of the immune system every day. Exposure to just one bacteria will trigger our body to form between two and six thousand different antibodies.

The food we eat, the water we drink, the air we breathe, the dust we work around, the animals we have as pets—all of these will expose us to thousands upon thousands of items that will cause us to form millions upon millions of different antibodies.

So, it is hard to see how a few extra vaccines could cause a huge disaster. (There’s even evidence that being so “clean” these days has increased our risk for asthma and other auto-immune disorders—we probably don’t get exposed to enough bacteria and dirt. But, that’s a topic for another time.)

A past study showed that the number of vaccines given in the first year of life had no impact on whether a child developed autism.[7]

Now, a new study has just been released, demonstrating that the number of antigens stimulated does not influence the development of autism.[8]

Simply put, if you are given more vaccines that stimulate more antibodies, this doesn’t affect your risk of autism either. So, that’s a further nail in the coffin for theory #3 (which doesn’t make much sense even on the face of it, since the number of antigens we’re adding with vaccines is miniscule compared to the total that a child is exposed to in the course of daily life).

And, it’s one more nail in a theory that has never had any real scientific support at all—except “support” manufactured by Andrew Wakefield.

A single lie can do a lot of damage.

And, Andrew Wakefield told a lot of lies.

Postscript

And, interestingly, there’s another nail in the “too many vaccines” argument too.

It is true that children today receive more “shots” than children in (say) the 1990s (or the 1950s).

But, what is interesting is that although the number of shots has risen, the number of antigens has dropped.

Why?

Here’s a simple example. We used to vaccinate against pertussis with a whole-cell, killed bacteria. That single bacteria caused the body to make around 3,000 antibodies—because the bacteria was coated with about 3,000 proteins or glycoproteins, all of which the body recognized as a bad, foreign invader.

Now, we have an “acellular” pertussis vaccine. This uses just a bit of the protein coat to create immunity, not the whole bug. Guess how many antibodies it stimulates? Six or less.

Bottom line, a child following the US guidelines in 2013 is exposed to only 315 antigens over the first two years of life from vaccines. In the 1990s, that number was in the several thousands.[9]

And, it’s really hard to see how 315 extra antigens—a drop in the bucket of what your immune system deals with each and every day, if not each and every hour—could do any harm. And, when you look at dozens of studies, that’s what it shows about autism.

Especially when they protect us from some of the most terrible diseases known to man.

So, do your kids and my kids a favor—ignore the fearmongers, and get your shots.


[1] Based on an article here: http://www.medscape.com/viewarticle/782298. I’ve expanded and added further explanation.

[2] See http://en.wikipedia.org/wiki/Andrew_Wakefield. I got some references from this article.

[3] Wakefield AJ, Murch SH, Anthony A et al. (28 February 1998). “Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children”. Lancet 351 (9103): 637–41.

[4] See TIME magazine’s article on “Great Science Frauds,” TIME Magaine, 13 January 2012.

[5] Meikle, James; Boseley, Sarah (24 May 2010). “MMR row doctor Andrew Wakefield struck off register”. The Guardian (London). Archived from the original on 27 May 2010

[6] “Thimerosal in vaccines: frequently asked questions (FAQs)”. Center for Biologics Evaluation and Research, FDA.

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