Vaccines and Autism
It is hard to imagine anything more precious than one’s newborn child. Part of the joy of raising a child is the corresponding hope one has for the future. Don’t we all wish for our children a life less fraught with the angst and struggles we ourselves endured? One of the less pleasant aspects of my job has the effect, at least temporarily, of robbing parents of that hope. This erosion occurs in the parent’s mind and heart as a consequence of a diagnosis I often have to provide. I am a psychologist employed in part to provide diagnostic evaluations of preschool age children suspected of having Autism. My intention is never to crush hope, instead it is to get the child on the right therapeutic path as early as possible in order to sustain as much hope as possible. However, uttering the word AUTISM in reference to one’s child constitutes a serious and devastating emotional blow.
Many parents come to my office very aware of their child’s challenges and the subsequent implications. They love their child, accept him as he is, and just want to do whatever they can to make his life better. Others come still steeped in hope that their child’s challenges are just a phase or believing that she is just fine. Regardless, most of them report that they suspected difficulties very early in the child’s development. For example, many note a lack of smiles, chronic agitation and difficulty soothing their child. Some children had not been calmed by being held or may have even resisted it. Some other children I see develop quite typically. They smile, giggle, rejoice at being held, coo and babble, and ultimately start to use a few words with communicative intent. The parents of this latter and rather rare subset, then watch in dismay as their child withdraws, often losing both functional communication and interest in other children.
The timing of this developmental back-slide most often occurs at around 18 months of age. This regression happens to coincide with the recommended timing of the provision of the Measles-Mumps-Rubella (MMR) vaccine. This temporal chronology is important as it has lead, in part, to a belief that the vaccine itself is responsible for the development of Autism. What these parents must experience at this time, I can only imagine, is a horrible combination of confusion and grief. They have had their hopes encouraged and reinforced only to have them vanquished. And it is human nature, under such circumstances, to look for a direct cause. It makes perfect sense that parents would, given the chronicity of events in some cases, suspect the MMR vaccine as the cause of their child’s regression.
During my occasional community talks on Autism, I often am asked about the alleged connection between vaccines and Autism. The coincidental temporal relationship between the provision of the MMR vaccine and this developmental decay leads to what Chabris and Simons in The Invisible Gorilla refer to as the Illusion of Cause. Chabris and Simons discuss how “chronologies or mere sequences of happenings” lead to the inference “that earlier events must have caused the later ones.” (2010, p. 165). By default, as a result of evolution, our brains automatically infer causal explanations based on temporal associations (Chabris & Simons, 2010).
At nearly every talk I give, there is someone in the audience who is convinced that their child (or a relative) is a victim of the MMR vaccine. Their compelling anecdotes are very difficult to refute or discuss. I find that the application of reason, or data, or both, misses the mark and comes off as being cold and insensitive.
For such causal relationships to endure and spread they often need some confirmation of the effect by an “expert.” This is where the story of Dr. Andrew Wakefield comes into play. Wakefield, a GI Surgeon from the UK published a paper in the prestigious UK medical journal, The Lancet, alleging a relationship between the MMR vaccine and the development of Autism. His “expert” opinion offered legitimacy to already brewing suspicions backed by the perceived correlates of increases in both vaccination and Autism rates, as well as the apparent chronology between the timing of the vaccines and the onset of Autism. Wakefield provided credibility and sufficient plausibility: and as a result, the news of the alleged relationship gained traction.
But hold on! There were major flaws with Wakefield’s study that were not initially detected by The Lancet’s peer review panel. First of all, Wakefield was hired and funded by a personal injury attorney who commissioned him to prove that the MMR vaccine had harmed his clients (caused Autism). His study was not designed to test a hypothesis: it was carried out with the specific objective of positively establishing a link between Autism and provision of the MMR vaccine. From the outset the study was a ruse, disguised as science.
Just this year (2010), 12 years after the initial publication of Wakefield’s infamous study, The Lancet retracted it and Dr. Wakefield has been stripped of his privilege to practice medicine in the UK. Problems however, surfaced years ago: as early as 2004, when 10 of 13 co-authors retracted their support of a causal link. In 2005 it was alleged that Wakefield had fabricated data – in fact, some of the afflicted children used to establish the causal link had never actually received the MMR vaccine!
Since the initial publication of this study, hundreds of millions of dollars have been spent investigating the purported relationship between vaccines and Autism. Despite extensive large scale epidemiological studies, there have been no replications of Wakefield’s findings. Children who had not been vaccinated developed Autism at the same rate as those who had received the MMR. There is no relationship between the MMR vaccine and the development of Autism. As a result of Wakefield’s greed, hundreds of millions of dollars have been wasted. Those dollars could have been devoted to more legitimate pursuits, and that is not the worst of it. I will get to the real costs in a bit.
Another aspect of the history of this controversy is associated with the use of thimerosal as a preservative in vaccines. This notion, which has also been debunked, gained plausibility because thimerosal contains mercury, a known neurotoxin. You may ask: “Why on earth would a neurotoxin be used in vaccines?” Researchers have clearly established that thimerosal poses no credible threat to humans at the dosage levels used in vaccines. However, given the perceived threat, Thimerosal is no longer used as a preservative in routine childhood vaccinations. In fact, the last doses using this preservative were produced in 1999 and expired in 2001. Regardless, the prevalence of autism seems to be rising.
It is important to understand that mercury can and does adversely affect neurological development and functioning. However, long term exposure at substantially higher doses than present in thimerosal are necessary for such impact. The mercury in thimerosal is ethyl-mercury, which is not fat-soluble. Unlike the fat-soluble form of methyl-mercury (industrial mercury), ethyl-mercury is flushed from the body very quickly. Methyl-mercury can be readily absorbed into fatty brain tissue and render its damage through protracted contact. Methyl-mercury works its way into the food chain and poses a hazard to us if we eat too much fish (particularly those at the high end of the food chain). In reality, one is at more risk from eating too much seafood (shark and tuna) than from getting an injection of a vaccine preserved with thimerosal. Yet there does not seem to be a movement to implicate seafood as the cause of Autism.
Even though the relationship between vaccines and Autism has been thoroughly debunked, there is a movement afoot, steeped in conspiratorial thinking, that alleges that “Big Pharmacy” and the “Government” are colluding to deceive the people and that elaborately fabricated data is used to cover up a relationship. This belief lives on. How can this be so? Even intelligent and well educated people I know are avoiding important childhood immunizations based on the fear and misinformation spread by these well intentioned people.
In 2003, in the UK, the MMR vaccine rate had fallen to below 79% whereas a 95% rate is necessary to maintain herd immunity. Currently, the vaccine rates are dropping in the US due to the efforts of celebrities like Jenny McCarthy who purports that her son’s Autism was caused by vaccines. McCarthy campaigns fiercely against childhood immunizations spurred on by the likes of Oprah Winfrey. Even folks like John McCain, Joe Lieberman, and Robert F. Kennedy, Jr have spread such misinformation. Continuing to contend that the MMR vaccine is the culprit, Wakefield has moved to the US and has risen to martyr status among the anti-vaccine folk. You need to know that just months before he published his seminal paper, Wakefield received a patent on a Measles Vaccine that he alleges, “cures” Autism. He has much to gain financially, in his attempt to scare people away from the current safe and effective MMR vaccine.
It amazes me that people do not automatically dismiss this alleged vaccine-Autism link. Wakefield’s conflict of interest and discredited research practices alone draw into question anything he has to say. The mountains of epidemiological evidence also favors rejection of a causal relationship between the MMR vaccine and Autism. However, the power of anecdotes and misguided beliefs place millions of children in harm’s way.
Imagine yourself as a parent of a child who cannot get the MMR vaccine because of a serious medical condition (e.g., cancer). Such vulnerable children, of which there are millions worldwide, depend on herd immunity for their very survival. Now imagine that your child is inadvertently exposed to measles by coming into contact with a child who wasn’t vaccinated (because of misguided parental fear). Because your child’s compromised immunity, she develops the measles and gets seriously ill or dies. Such a scenario, although improbable is not impossible. It is more likely today largely due to the diminished herd immunity caused by misinformation. Whooping Cough (Pertussis) is likewise posing serious concerns (and one documented death) in unvaccinated clusters because of the anti-vaccine folk. This myth persists, in part, because of the Illusion of Cause, and the consequences have become deadly. Next week I will delve into this Illusion that sustains this erroneous and dangerous belief system.
Association for Science in Autism Treatment. (2009). Autism & Vaccines: The Evidence to Date. Vol. 6., No. 1 http://www.asatonline.org/pdf/summer2009.pdf
Center for Disease Control. Autism Spectrum Disorders: Data & Statistics. http://www.cdc.gov/ncbddd/autism/data.html
Chabris, C. F., & Simons, D. J. (2010). The Invisible Gorilla. Random House: New York.
Plait, P. (2010). The Australian antivax movement takes its toll. Bad Astronomy Blog. http://blogs.discovermagazine.com/badastronomy/2009/04/26/the-australian-antivax-movement-takes-its-toll/