One common feature of unscientific belief systems is that they do not change in the face of new evidence. They tend to evolve like cultural beliefs or marketing campaigns, but do not appear to be affected by scientific evidence in any meaningful way.

One great example of this is the idea the autism is linked to vaccines (to be clear up front, it isn’t) This idea had a few important factors in its origin. The first was simply the existing anti-vaccine movement searching for anything to blame on vaccines. The second, and perhaps decisive, factor was the now discredited and withdrawn study by Andrew Wakefield linking autism to the MMR vaccine.

Even as the MMR claim was dying, the anti-vaccine community was moving onto the next target – mercury (specifically the preservative Thimerosal). This was the target of the book Evidence of Harm by David Kirby. This also created common cause between the anti-vaccine movement, and separate “mercury militia” blaming many modern ills on mercury, and some environmentalists (most prominently Robert Kennedy Jr.) who are keen to blame medical problems on any environmental exposure, including mercury and/or vaccines.

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Facebook is like a graveyard in a zombie movie, where old news items rise from the dead to have a second life. I am often asked about news items that are burning up Facebook, only to find that they are years old, but never-the-less they have to be addressed all over again. ]

One such item (actually a few items) is a 2012 news report about the Italian courts awarding money to the Bocca family a large reward because it concluded their 9-year-old son acquired autism from the MMR vaccine.

History here is a useful guide. The courts have historically often been out-of-step with the science, tending to err on the side of awarding compensation for possible harm. For example, until about the 1920s it was thought that physical trauma could cause cancer. Animal studies and epidemiological evidence, however, showed that there was no causal connection. Recall bias and increased surveillance were likely the cause of the apparent association.

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It’s always amusing to see two pseudosciences combined into one greater pseudoscience – it’s like chocolate and peanut butter. It’s not uncommon because those who would embrace one pseudoscience are likely to follow the same flawed logic and process to accept others. My colleague David Gorski has termed this effect “crank magnetism.”

Take, for example, Gian Paolo Vanoli. He has been making international headlines recently because of his claim that vaccines cause homosexuality, which he insists is a disease. The story appears to have been first picked up in English by the Huffington Post – all other reports of this story I have found cite this article as their source.

Because of the date of this article (4/1) I wanted to make sure I had another source, but the only other sources are in Italian. The story does seem to check out – here is one article: Gian Paolo Vanoli: Cricket on the urine that has been around the world. 

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Another study, published recently in PLoS One, fails to show a correlation between mercury and autism. This was a study of mercury excretion in the urine, comparing subjects with autism to their siblings as well as controls without autism spectrum disorder (ASD), both in mainstream and special schools. They found no significant difference among the groups, even controlling for kidney function (creatinine clearance), age, gender, and amalgam fillings.

To put this study into context – there are those who claim that mercury toxicity is what causes ASD, and in fact ASD is simply misdiagnosed mercury toxicity. There is no question that mercury is indeed a neurotoxin, but toxicity is all about dose, so the question is are children being exposed to mercury in high enough dose to cause toxicity. Further, it is difficult to extrapolate from preclinical studies (in test tubes and petri dishes) to living organisms. We need to further know what happens to the toxin in the body, and how the body handles it.

With regard to the forms of mercury found in some vaccines (although much less than in previous years) and tuna fish, the body seems to rid itself of the mercury sufficiently quickly to prevent build up to toxic levels. Of course, this remains a hot topic because of the persistent claims by the anti-vaccine movement that vaccine cause ASD, and some who cling to the discredited notion that it is mercury in vaccines that is the culprit. There are also the so-called “mercury militia” who blame environmental mercury (from vaccine and elsewhere) on all human illness, not just autism.

As further background, it’s helpful to note the chain of argument that has occurred with respect to the role of mercury in autism. Studies have consistently found no correlation between mercury exposure and the risk of ASD. Proponents of the mercury hypothesis have therefore argued that there is a subpopulation of vulnerable children who metabolize and excrete mercury differently than the general population, and it is within this subpopulation that mercury causes ASD.

Logically this may be true, but the argument is little more than special pleading, although a common one. Scientists are familiar with the usual list of special pleading arguments made to dismiss negative evidence. These include: that the dose studied was too low, the treatment duration was too short, the placebo or comparison treatment was also effective, or the looked-for effect only exists in a subpopulation. Each one of these arguments is logically consistent – if true they would explain the negative results without meaning that the phenomenon is not true. They may even be true in specific cases. What makes them special pleading is when they are invoked ad hoc to explain negative evidence without good justification.

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(Cross-posted at Science-Based Medicine.)

Labels are a cognitive double-edged sword. We need to categorize the world in order to mentally capture it – labels help us organize our mental maps of the overwhelming complexity of things and to communicate with each other. But labels can also be mental prisons, when they substitute for a thorough, nuanced, or individualized assessment – when categorization becomes pigeon-holing.

We use many labels in our writings here, out of necessity, and we try to be consistent and thoughtful in how we define the labels that we use, recognizing that any sufficiently complex category will be necessarily fuzzy around the edges. We have certainly used a great deal of electrons discussing what exactly is science-based medicine, and that the label of so-called alternative medicine is really a false category, used mainly for marketing and lobbying (hence the caveat of “so-called”).

We get accused of using some labels for propaganda purposes, particularly “antivaccinationist” (often shortened to “antivaxer”). Also “denier” or “denialist”, as in germ-theory denier. Even though we often apply labels to ourselves, no one likes having an unflattering label applied to them, and so we have frequent push-back against our use of the above terms.

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In a recent article in The Canadian, journalist Anthony Gucciardi trots out long discredited anti-vaccine canards in the guise of actual journalism. The piece is poorly researched and resourced, blatantly biased, and amounts to little more than irresponsible fear-mongering about the flu vaccine.

Gucciardi writes:

Each dose of flu vaccine contains around 25 micrograms of thimerosal, over 250 times the Environmental Protection Agency’s safety limit of exposure.

Mercury, a neurotoxin, is especially damaging to undeveloped brains. Considering that 25 micrograms of mercury is considered unsafe by the EPA for any human under 550 pounds, the devastating health effects of mercury on a developing fetus are truly concerning.

Everything Gucciardi wrote is either outright factually wrong, or incomplete in a way that makes it highly misleading.

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The intellectual dishonesty, or such blinkered stupidity that it is indistinguishable from this, of the anti-vaccine crowd is always a spectacle. J.B. Handley is a prime example. He has made himself into an intellectual bully, and internet thug for the Age of Autism.

In a recent piece for this wretched hive of anti-vaccine propaganda, Handley write:

“It’s been asked and answered, vaccines don’t cause autism.”

This lie, it really drives me nuts. More, and I can say this and mean it, anyone who repeats this lie is immediately my enemy. I mean that, I really do, because there are just too many kids in the mix and this is just too important and if you are either intellectually too lazy or too dishonest to understand the science around vaccines and autism, then, well, you are my enemy. Sorry, it’s a hard knock life.

That captures his “Goodfellas” approach quite nicely. If you disagree with him – you are his enemy, the gloves are off, and anything is justified. To add irony to his thuggery, Handley himself is just too intellectually lazy, or (in my opinion) scientifically illiterate to “understand the science around vaccines and autism.” Yet he presumes to lecture those who have dedicated their lives to studying science, and in fact is willing to make them his enemy because they have the audacity to point out that his understanding of science is hopelessly flawed.

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The US Supreme Court is about to hear a case involving an alleged vaccine injury. This one does not involve thimerosal, MMR, or autism – it involves neurological injury allegedly from an older version of the DTP vaccine. However, this case would have implications for the many autism-related claims being made.

The case is not about the facts of the claim – whether or not the DTP actually caused any injury in this case, that of Hannah Bruesewitz, but rather about the vaccine court and the ability of parents to bring suits against vaccine manufacturers.

In 1986 the National Childhood Vaccine Injury Act created a special court, the vaccine court, the purpose of which was to provide an alternate method for determining who deserves compensation for a possible vaccine injury. The vaccine court functioned to protect both citizens and vaccine manufacturers. It provides an expedited route to compensation, with a generously low threshold for evidence. For certain listed injuries, compensation is automatic.

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This is a quick update on the Autism Omnibus hearings – representative cases heard before a special court to decide if there is any credible evidence to conclude that autism may be a vaccine injury. After hearing exhaustive testimony by all sides, the special masters determined that the evidence does not support a link between autism and vaccines.

One of the cases heard was the Cedillo case, which was used as the test case for the theory that the MMR vaccine plus exposure to thimerosal can trigger brain damage that looks clinically like autism. In February of 2009 the court rejected the claim that Michelle Cedillo’s autism was caused by vaccines. No only was the theory of causation without scientific backing, evidence was presented to show that Michelle Cedillo demonstrated early symptoms of autism prior to ever receiving the MMR vaccine.

In fact the Cedillo case is representative of a fact that scientific research is increasingly demonstrating – that subtle signs of autism are present prior to parents noticing that there is a problem and long before formal diagnosis. The consensus of evidence is that signs of autism appear between 6-12 months of age, and maybe earlier in some cases. Meanwhile, the first MMR vaccine is given at 12 months. Since causes must precede effects, this fact alone is fatal to the MMR-autism hypothesis.

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One of my goals in writing for this blog is to educate the general public about how to evaluate a scientific study, specifically medical studies. New studies are being reported in the press all the time, and the analysis provided by your average journalist leaves much to be desired. Generally, they fail to put the study into context, often get the bottom line incorrect, and then some headline writer puts a sensationalistic bow on top.

In addition to mediocre science journalism we also face dedicated ideological groups who go out of their way to spin, distort, and mutilate the scientific literature all in one direction. The anti-vaccine community is a shining example of this – they can dismiss any study whose conclusions they do not like, while promoting any horrible worthless study as long as it casts suspicion on vaccines.

Yesterday on Age of Autism (the propaganda blog for Generation Rescue) Mark Blaxill gave us another example of this, presenting a terrible pilot study as if we could draw any conclusions from it. The study is yet another publication apparently squeezed out of the same data set that Laura Hewitson has been milking for several years now – a study involving macaque infants and vaccinations. In this study Hewitson claims a significant difference in brain maturation between vaccinated and unvaccinated macaque infants, by MRI and PET analysis. Blaxill presents the study without noting any of its crippling limitations, and the commenters predictably gush.

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