Is there evidence that the MMR vaccine causes autism? Part 3: possible bias
Possible biasIs it possible that the multiple studies which found no connection between the MMR vaccine and autism can be explained by a comprehensive, systemic bias in favor of Big Pharma? I don't think that this bias is a legitimate possibility for several reasons:
First, the breadth of the papers I've cited above make comprehensive, systemic bias unlikely. The research I presented was not produced by a single research team or in a single journal or using data from a single country. Instead, they represent a large number of studies all published in extremely prestigious journals from researchers all over the world. To suggest that all of this research was manipulated by Big Pharma requires more than one or two isolated instances of fraud; it would require a vast conspiracy among scientists, journal editors, referees, and governmental health organizations. Second, this kind of comprehensive, systemic bias makes it hard to explain how Dr. Wakefield's study was published in the first place. If Big Pharma really has such sweeping influence over all of these various medical journals and the media, how did the Lancet end up publishing his article and why did the media initially greet it with such publicity? Third, the market recalls of highly lucrative drugs makes it untenable to claim that Big Pharma has a stranglehold on the medical literature. For example, in recent years, drugs such as Fen-Phen (1997), Rezulin (2000), Baycol (2001), and Vioxx (2004) have all been recalled by the FDA due to safety concerns that were exposed by clinical studies. But if Big Pharma has the power to silence or marginalize any scientific study which threatens their profits, why would they have failed to do so in these cases? Note that I am not denying here that there is a 'Big Pharma' lobby, that it is powerful, and that it -like any other lobby- can engage in unethical and even reprehensibly evil practices. I'm merely pointing out that it is not very plausible to explain all the evidence I've presented with an appeal to this kind of vast conspiracy.
Next, since we are trying to remain objective, we need to consider the alternative possibility: what if there was a bias on the part of Dr. Wakefield or his coauthors which could account for the discrepancies between his initial study and later studies? Here, my goal is not to draw firm conclusions about Dr. Wakefield's character or motivations, which are largely beyond my (or anyone else's) grasp. I only want to consider information that might be relevant to the validity of his original publication.
As many probably know, subsequent to the publication of his original article, Dr. Wakefield was subject to the longest trial in the history of the UK's General Medical Council (GMC), which oversees the certification of doctors who practice medicine in England much like the National Board certifies all doctors licensed to practice medicine in the United States. (Note that the trial was not convened to determine whether Dr. Wakefield's research was correct; scientists and doctors mistaken in their research claims are not always liable to censure. Instead, the GMC was investigating charges that Dr. Wakefield had engaged in unethical medical practices.) In 2010, Dr. Wakefield was found guilty of numerous charges and was stripped of his right to practice medicine in the U.K. Let's consider three of the most troubling charges below.
First, Dr. Wakefield was accused of several unethical practices in the course of his research. For example, Dr. Wakefield took blood samples from children at his son's birthday party. A video of Dr. Wakefield confirming this incident, during which he states that two of the children fainted and one vomited, is available here. The GMC also concluded that several of the 12 autistic children enrolled in the study were subjected to invasive and painful procedures such as colonoscopies that were contrary to their medical interests. The final GMC report included multiple instances where Dr. Wakefield had failed to apply for and obtain permission from the Ethics Committee to carry out various procedures on his patients. If the GMC was correct in finding Dr. Wakefield guilty, these charges constitute a major violation of medical ethics, which has very strict rules regarding the use of human subjects in medical experiments.
Second, investigation by the GMC brought to light several instances of financial conflicts of interest. In 1996 -two years before the publication of the Lancet study- Dr. Wakefield and a lawyer named Richard Barr were awarded £ 55,000 (see page 5,6 here) by the Legal Aid Board to support research attempting to prove that the MMR vaccine was causing injury to children, as part of lawsuit against pharmaceutical companies. The autistic children eventually enrolled in Wakefield's study were also litigants in the lawsuit, meaning that if Dr. Wakefield's research was successful, the children would be more likely to win their lawsuit. Dr. Wakefield did not report this conflict of interest either to the Ethics Committee or to the Lancet when his paper was published. Six months prior to the publication of the Lancet study, Dr. Wakefield also filed an application for a patent on a new measles vaccine that he claimed to have invented which would replace the MMR vaccine then in use. Additionally, over the next 9 years, Dr. Wakefield received £ 400,000 as a consultant in this lawsuit. The facts that Dr. Wakefield received hundreds of thousands of pounds from anti-vaccine lawyers and that his research subjects were involved in an anti-vaccine lawsuit at the time of his study constitute a tremendous financial conflict of interest.
Third, a lengthy investigation into the individual children enrolled in Dr. Wakefield's original study suggested that many of them had exhibited autistic symptoms prior to their MMR vaccination, but that the data were altered to suggest a connection between the MMR vaccine and autism. The entire report can be found here. Fiona Godlee, the editor-in-chief of the British Medical Journal which commissioned the investigation, concluded that while "[i]t's one thing to have a bad study, a study full of error... in this case, we have a very different picture of what seems to be a deliberate attempt to create an impression that there was a link by falsifying the data." Problems with the original study led 10 of Dr. Wakefield's 12 coauthors to retract their interpretation of the data in 2004, and led the Lancet to retract the paper entirely in 2010.
Now, as I have said, I have no desire at all to speak definitively about Dr. Wakefield's motivation. The main question before us is whether, given this information, it is more likely that the numerous, independent researchers who found no link between the MMR vaccine and autism are wrong or whether it is more likely that Dr. Wakefield's original study was wrong. I urge readers who are unsure about the credibility of the claims made above to click through the links I've provided, which come from various news outlets, medical journals and licensing boards. Of course, it is possible that all of these sources are either accidentally incorrect or are deliberately deceiving the public. But one must again consider which is the more likely explanation: that all major news agencies are controlled by Big Pharma, along with all major scientific publications and governmental health agencies? Or that Dr. Wakefield's original study was wrong?
The question of whether or not to vaccinate our children is a weighty one and -unfortunately- not one that we can avoid. Given the importance of this decision, I wanted to discuss the evidence we have at our disposal so that parents can make an informed decision about what is in the best interest of the child. From the evidence I've gathered so far, it seems that an extremely strong case can be made that the MMR vaccine does not lead to autism. First, the original study that prompted this concern insisted that 1) it had not proven a link between the MMR vaccine and autism and 2) stated that follow-up research was needed to test their claims. Yet no subsequent study was able to duplicate Dr. Wakefield's results, and numerous other studies found no link between MMR vaccination and autism. Second, muitiple independent studies by different researches at different institutions showed that unvaccinated children have just as great a risk of autism as vaccinated children. This piece of evidence, to me, is the most compelling. If the MMR vaccine causes autism, then shouldn't we expect to see a significantly lower rate of autism in children who were left unvaccinated? And if we don't, can we really argue that leaving our children unvaccinated will lower their risk of autism? Third, I pointed out that Dr. Wakefield's original study had been retracted from The Lancet and that 10 of his 12 co-authors had withdrawn their support from it's claim that vaccines and autism were linked. It is hard to explain the journal's retraction and the withdrawal of Dr. Wakefield's coauthors if the original study was scientifically sound. Finally, I mentioned that Dr. Wakefield lost his license to practice medicine in England over breaches of medical ethics, and that he had received tens of thousands of pounds from lawyers seeking a link between the MMR vaccines and autism. Now, obviously, this conflict of interest by itself doesn't prove that the study's results were incorrect. But, taken together with all of the other evidence I've cited, I think it is very troubling.
Given the importance of this decision and how deeply our beliefs about it can run, I do not necessarily expect that this single essay will immediately change someone's opinion. At the very least, I think readers will want to follow the links I've provided -almost all of them to primary sources- to see if my claims are correct. What, then, do I hope readers gain from what I've written?
First, I hope that this essay calls attention to claims that you may never have considered. In doing research on this subject, I learned quite a bit of new information, from both pro- and anti-vaccine sites, which I then had to incorporate into my beliefs about vaccines. For example, I first learned on an anti-vaccine website that the pertussis (whooping cough) vaccine has a relatively low effectiveness and that recent outbreaks of pertussis are probably not due to a drop in vaccination rates. This information was confirmed not only by anti-vaccine sites, but by pro-vaccine sites and multiple media sources. Given that I had assumed -incorrectly- that all vaccines were extremely effective, that new information required me to alter my belief. In the same way, if much of the material I presented in this essay is new to you, then it may be worth reevaluating your beliefs.
Second, the writing of this essay has made me realize how confusing the Internet can be, even to those who genuinely want to know the truth. As I've already said repeatedly, the best way to separate fact from fiction on the internet is to consult multiple sources with widely diverging viewpoints. Seek out both sides of the debate and weigh the evidence they present. Look for primary sources (interviews, legal documents, scientific studies). Even if you are not a scientist, the main conclusions of research articles are always summarized in the abstract, so try to read the article yourself rather than trusting a secondary source to tell you what the article says. Look for sites and sources which at least attempt to take an impartial tone and focus more on information than on accusation. That is not to say that clearly partisan sites cannot contain valid information, but rhetoric and emotion can often mask questionable interpretation of data.
Finally, I hope that this essay causes us to reflect on our own emotional commitment to certain beliefs and how hard it can be to change them. I suspect that parts of this essay made many people uncomfortable on both sides of this issue. For example, I'd imagine that some of the information regarding Dr. Wakefield's ethical practices and financial ties elicited an immediate, emotional response from people who view him positively. In the same way, I'd also imagine that some of the statements I made about the possibility of biased research or the possibility that anti-vaccine sites contain valid information elicited an immediate, emotional response from people who are strong proponents of vaccines. All human beings -myself included- can feel defensive when deeply-held beliefs are challenged. But we have let our reason guide our emotions. Truth might be hard to find, unexpected, and even uncomfortable. But we need to remain open to it.
Was any of the information in this essay new to you? Is there relevant information I did not consider? I would very much like to hear your thoughts; feel free to e-mail me at Neil -AT- Shenvi.org
- Science and religion: is it either/or or both/and?
- Why should we believe that Christianity is true?
- Why I am a Christian
If you're surprised that an evangelical Christian would appeal to evidence and reason, please take a look at some of the links I provided at the end of this essay. I also highly recommend the book The Reason for God by Tim Keller. It is phenomenal. Free sermons treating many of the topics covered by this book can be found here.