I must admit that, after having taken it easy over the last few days, when the time came to sit down and get back into the swing of things, I had a bit of a hard time. No, it’s not just blogging. That’s actually a rather minor component of the whole malaise that descended upon me like a shroud. Rather, it’s the simple fact that the Labor Day weekend in the U.S. represents the unofficial end of the summer season. After that, it’s all back to school, back to work, back to the grind.
Back to real life after summer.
This reluctance, not surprisingly, seeped out of real life and started to permeat blog life. What I needed was something to get me going again with enthusiasm. For a moment, I wished I had held back my post from Sunday, because, despite (or perhaps because of) its being uncharacteristically brief for me it was actually one of my better posts. Fortunately, though, for skeptical bloggers, particularly those who have made the depredations of the anti-vaccine movement one of his favorite topics, there exists a gold mine of anti-vaccine woo that almost never fails to provide fresh
meat blogging material for a skeptical blogger to sink his teeth into. There, although there are several bloggers, there is one who is capable of illustrating the arrogance of ignorance better than any other. Yes, I’m referring to Age of Autism as the blog, and the blogger is Mark “Not a Doctor, Not a Scientist” Blaxill, who yesteray was crowing There’s a Funny Thing About Evidence: More Support for Autism-Mercury Link. Let’s just put it this way. There is a funny thing about evidence. It’s just not “funny” in the way Blaxill thinks it is, as the entire AoA crew will find out in the near future and about which I can’t say more–for now.
In the meantime, let’s take a look first at what Blaxill says about the study that he is presenting as “evidence” that thimerosal in vaccines causes autism, and then at the study itself. It’s quite amusing to see someone so talented at so thoroughly deluding himself:
Despite the relentless drumbeat of propaganda from the CDC, public health authorities and the thuggish on-line goons of the medical industry, there’s a funny thing going on. The evidence of a connection between mercury exposure and autism keeps growing.
On what planet? I asked myself as I read Blaxill’s post. After all, if there’s one thing that I’ve covered again and again and again over the five-plus years that I’ve been regularly blogging about the vaccine-autism manufactroversy, it’s that the evidence is going in exactly the opposite direction to what Blaxill proclaims it to be going. For example, in terms of neurodevelopmental outcomes, Thompson et al, although not explicitly studying autism, showed no detectable difference in non-autism neurodevelopmental outcomes in children who received thimerosal-containing vaccines and those who did not. Meanwhile, large epidemiological studies from Italy, California, Demark, and elsewhere have all come to the same conclusion: There is no detectable correlation between thimerosal-containing vaccines and the subsequent risk of developing autism or autism spectrum disorders. Yet, despite this tsunami of evidence (sorry, couldn’t resist), all members of the mercury militia like Blaxill can do is to stick their fingers in their ears and repeat at high volume, “La la la la la, I can’t hear you.” Well, that, and producing truly execrable studies like the highly unethical Hewitson et al study that abused baby Macaque monkeys in the name of an improbable hypothesis, as I described back in July. By coincidence, that particular study appeared in a “special issue” of a Polish journal that I had never heard of before, Acta Neurobiologiae Experimentalis (ANE). By no coincidence, I’m sure, one of the articles that Blaxill trumpets as evidence that the thimerosal/mercury/autism link pining for the fjords, so to speak, also comes from that very same “very special issue” of ANE. It also comes from everybody’s favorite “I’m not anti-vaccine” proclaimers Mary DeSoto and Robert Hitlan, who famously got in a rather amusing exchange with bloggers who piled on their earlier less than scientifically stellar work. This time around, they’ve managed to impress Blaxill (not difficult if you write something that suggests that vaccines can cause autism, virtually impossible if you present actual science) with a review article that Blaxill describes as follows:
They asked a simple question: what does the published evidence linking autism and mercury really say? To answer that question, they did a simple Pub Med search. They searched for the terms “(Autism AND Mercury) OR (Autism AND Heavy Metals)”. They found 163 articles (a number that has since risen to 174) and reviewed them. According to the authors, “Of these 163 articles, 58 were research articles with empirical data relevant to the question of a link between autism and one or more toxic heavy metals. Fifteen were offered as evidence against a link between exposure to these metals and autism. In contrast, a sum of 43 papers were supporting a link between autism and exposure to those metals.” In short, 74% of the published studies supported the theory.
It’s at this point that Blaxill melts yet another one of my irony meters. I tell ya, I really need to buy a few dozen of them and stash them away in my basement, so fast are promoters of pseudoscience tearing through them these days. I should probably make up some sort of armor plating for them, preferably heat resistant to deflect all the burning stupid like what Blaxill lays down:
Evidence is a funny thing.
To which I respond again: It sure is, just not in the way you think it is. On second thought, I’d have to armor those irony meters like the black box flight recorders on commercial airliners, and even then that might not be enough to protect them. It’s probably cheaper just to let people like Blaxill fry the occasional irony meter and just replace the damned thing with the cheapest version I can, knowing the next one will be fried again before too long.
Given that Blaxill is not exactly known for his scientific chops, his delusions otherwise notwithstanding, I went and looked at the article to which he referred. Oddly enough, Blaxill didn’t really spin or misrepresent what DeSoto and Hitlan wrote. He didn’t have to. What they wrote pretty much basically, when stripped of the scientese, consisted of an argument that because there are more articles that report a link between vaccines and autism a link must be plausible. Of course, in the meantime, they butcher the interpretation of at least one study, specifically Thompson et al:
For example, Paul Offit concludes that Thompson and others (2007) study “found no evidence of neuro- logical problems in children exposed to mercury-con- taining vaccines” (Offit 2007, p. 1979). But is this really true? According to the article’s authors, they detected only a “few significant associations with exposure to mercury” (Thompson et al. 2007, p. 1281). Of some interest to the question of early exposure and autism, “Increasing mercury exposure (in the first month of life) was associated with poorer performance of a measure of speech articulation.” (Thompson et al. 2007, p. 1281), although this finding is in need of repli- cation, it is of interest since poor articulation occurs in those with autism (Shriberg et al. 2001). Among boys, higher mercury exposure during the first month was associated with an increase in performance IQ. This is again interesting because children with autism are known for having an uneven IQ performance such that their performance IQ is often higher than their verbal IQ (Ehlers et al. 1997). To be sure, overall, the results are not overwhelming and the inclusion of so many measures (42 different outcomes) makes it plausible to write off the few significant results as chance occur- rences. But if the aim of the study was meant to see if thimerosal might relate to autism, future research may want to target specific measures based on the autism literature and make specific predictions. If the aim was to see if thimerosal relates to general cognitive skills, it would have been wise to select tests previously shown to relate to mercury exposure.
This is, of course, utter nonsense. As I pointed out (as did Autism Natural Variation), Thompson et al noted a handful of neurodevelopmental measures that improved as well as showed a detriment. In fact, there were correlations between thimerosal-containing vaccines and improvements in 12 measures and declines in 8 measures. Statistically, this result is perfectly compatible with a wash, random noise, given the large number of comparisons done. Here, Hitlan and DeSoto are doing exactly what the anti-vaccine maven Sallie Bernard did after the study and focusing on the handful of negative correlations and ignoring the positive correlations. Sorry, science doesn’t work that way. You can’t just cherry pick the correlations you want to take seriously. If you’re going to harp on the negative correlations as evidence that thimerosal has a negative impact on neurodevelopmental outcomes, intellectual honesty demands that you equally acknowledge the positive outcomes detected and consider the hypothesis that for those particular measures thimerosal-containing vaccines might actually improve neurodevelopmental outcomes. Given that the correlations noted were all very small and close to evenly distributed both positive and negative, the most appropriate interpretation is that they are random noise. That Hitlan and DeSoto apparently can’t see that should tell you all you need to know about their methodology.
But what is the second bit of “funny” evidence? This, according to Mark Blaxill:
Last week, yet another important study was published with no fanfare in the mainstream media. A research team in Warsaw led by Dr. Dorota Majewska published the latest findings from their ongoing investigation of the effect of thimerosal administration on newborn rats. I wrote about the first published findings from this project HERE. In their latest paper, the authors extended their investigation of the potential relationship between thimerosal and the development of opioid receptors in the infant brain. They found that thimerosal at the same concentrations received in human infants had clearly measurable effects on opioid receptor development in the infant rats. They also found that these effects were stronger at higher doses. The effect was found to be persistent, lasting well beyond the initial period of administration. According to the authors, “very likely, it is permanent.”
This is another study that is arguably an abuse of animals. True, it’s not as egregious as the Hewitson et al study, but it’s still quite dubious. Basically, what Majewska’s group did was to test the effect of injecting thimerosoal in newborn suckling rats. Rats were dosed with either thimerosal at 12-3,000 μg Hg/kg (actual doses: 12, 240, 1,440 or 3,000 μg Hg/kg) or saline control intramuscularly at age 7, 9, 11, and 15 days. At 20 weeks, the rats were killed and their brains sectioned and stained for the mu opiod receptor (MOR). There was also a separate group receiving the lower doses of thimerosal who were killed at 8 weeks in order to examine their brains. Investigators reported that thimerosal administration caused dose-dependent statistically significant increase in MOR densities in the periaqueductal gray and caudate putamen, but decrease in the dentate gyrus, where it was accompanied by the presence of degenerating neurons and loss of synaptic vesicle marker (synaptophysin).
The authors claim that the lowest dose (12 μg Hg/kg) is equivalent to the amount of thimerosal contained in vaccines given in some countries, something I had a hard time believing; so I decided to look it up. I went to the website of the evil empire itself, the FDA, which confirms my memory (given that it’s been a long time since I looked up this information) that a typical thimerosal-containing vaccine contained between 0.003% and 0.01% thimerosal. That means that, at the highest concentration, a typical 0.5 ml dose of vaccine contains around 25 μg Hg. So, for such a vaccine, a child would have to weigh 2 kg to be receiving a dose “equivalent” to the lowest dose used in this study. That’s rather on the small side even for a newborn infant, and, given that the only vaccines that contain more than trace thimerosal, are flu vaccines, very small compared to a child at least six months old, which is the youngest age at which the flu vaccine is recommended. The median weight for a six month old boy is on the order of 13 lbs, or around 5.9 kg. For 25 μg Hg, that’s around 4.2 μg Hg/kg. It’s even worse than that, though. The investigators repeated the dose four times in one week, which adds up to a minimum dose received of 48 μg Hg/kg (more than 11 times what would be considered a “typical” dose of thimerosal for a human infant), and the maximum dose received was a whopping 12,000 μg Hg/kg, or 12 mg Hg/kg, nearly 3,000 times a “typical” dose for a human infant!
These calculations aside, it should be emphasized once again that virtually no pediatric vaccines contain thimerosal above trace levels other than certain flu vaccines (which aren’t administered before 6 months of age anyway), and there are thimerosal-free alternatives. Basically, the authors are stretching the definition of “equivalent” almost beyond recognition when they claim that their dose is equivalent to what some childhood vaccines provide.
There were a number of other dubious aspects to this paper. For one thing, it is not stated whether those doing the sectioning and counting of the rat brains were blinded to experimental group. True, most of the counting was done using automated image analysis software, but that does not obviate the need for blinding in rigorous experimental technique. After all, it’s a human who selects the sections and images that the software counts. Another thing that confused me was the methodology used to determine the time frames when the brains were examined. Basically, the rats receiving the two lower doses were examined at eight weeks; the two higher doses, at 20 weeks. One thing that I noticed right away is that at 8 weeks, the group receiving 12 μg Hg/kg was reported to have a two- to three-fold increase in MOR density in two of the regions of the brain identified, but then I looked at the statistics and saw that neither value achieved statistical significance! Yet the authors had the gall to write:
A marked THIM-induced, dose-dependent increase of MOR density was found in the PAG–the midbrain region associated with pain modulation [18-20]. The effect was clearly noticeable already at the lowest dose of THIM (12 lg Hg/ kg), equivalent to those used in pediatric vaccines, although at this dose it did not reach statistical significance.
Sorry, but “clearly noticeable” doesn’t cut it. If the result didn’t even come close to achieving statistical significance, then there was no difference. Sorry, Charlie. Of course, there was a statistically significant difference at the next dose level up, but that dose level was 20 times higher! I’m perfectly willing to believe that that dose could cause changes in the brain. Ditto dose levels 250 times higher than the lowest dose level of 12 μg Hg/kg. 3 mg/kg Hg is a rather large dose. In any case, there is nothing in this paper that convincingly demonstrates changes in the brain due to thimorosal at anything near the doses received by a typical child in vaccines–or arguably even received by a typical child ten years ago, before thimerosal-containing childhood vaccines were taken off the shelf. The closest that comes to it is a measurement of synaptophysin, which is a measure of the number of synapses in a given area, and even then the results are not particularly convincing, given the lack of blinding and what appears to be a barely statistically significant result found only in one area of the brain and in only one outcome measured. That doesn’t even consider the authors’ choice of one-way ANOVA for a statistical test when a dose-response analysis would probably have been better.
The authors conclude:
In conclusion, this study documents that parenteral administration of THIM to suckling rats at doses equivalent to those used in pediatric vaccines or higher produces lasting alterations of MORs in several brain regions and damage to neurons. If analogous changes occur in the brains of some children, they are likely to have profound neurological, physiological and behavioral consequences, which may be relevant for certain neurodevelopmental disorders. These data argue for removal of THIM from all infant vaccines.
Poppycock. This study documents nothing of the sort. As I’ve documented, in reality, even the smallest dose is not “equivalent” to what infants receive, in particular since thimerosal has been removed from nearly all infant vaccines and given that the authors repeated the dose four times over the course of one week. Moreover, this study doesn’t even find a statistically significant difference in the MOR density of the brains of infant rats that can be attributed to the lowest dose thimerosal used (you know, the one that’s supposed to be “equivalent” to what infants receive), and the one measure in which it does purport to find a statistically significant difference is not particularly convincing. In other words, this study tells us that very high doses of mercury in the form of thimerosal is toxic to the brain. Tell us something we didn’t already know. Too bad the authors forget the old adage in pharmacology of “the dose makes the poison.” In fact, they forgot it to the point where they didn’t even include doses of thimerosal that were legitimately similar and bracketing the dosage that an infant might receive even from the old thimerosal-containing vaccines that are no longer used.
Mark Blaxill may think that “science is funny,” but in reality all he’s pushing is “funny science.” And I don’t mean humorous science, as there is nothing humorous about the sacrifice of so many rats to try to show that thimerosal causes autism. It is, however, humorous to see Mark “Not a Doctor, Not a Scientist” Blaxill desperately spin the study as evidence that, any day now–any day!–the tide will turn and the mercury militia will be vindicated.