Search Results for "thimerosal"

Feb 16 2012

Mercury Still Not Correlated with Autism

Published by under autism,Neuroscience

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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17 responses so far

Dec 28 2011

What Is an Antivaxer?

(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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10 responses so far

Oct 21 2011

Fear Mongering the Flu Vaccine

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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58 responses so far

Jan 27 2011

Some Nonsense from J.B. Handley

Published by under autism

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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13 responses so far

Oct 12 2010

Vaccine Suit to be Heard by Supreme Court

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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26 responses so far

Sep 01 2010

Appeals Court Rejects Autism-Vaccine Link

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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26 responses so far

Jul 16 2010

Terrible Anti-Vaccine Study, Terrible Reporting

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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21 responses so far

May 25 2010

Vaccines – Too Few, Too Late

The anti-vaccine movement is nothing if not savvy about marketing their nonsense – at least in the last decade. One of their successful slogans has been “too many, too soon” – implying that children are receiving too many vaccines while they are still too young to deal with them. The result, anti-vaccinationists argue, is potential neurological toxicity or “overwhelming” the immune system.

The slogan also serves double duty, allowing anti-vaccinationists to argue that they are not “anti-vaccine” just “pro-safe vaccine.” This is just more marketing savvy, however – a deliberate deception, as many of the people who make this claim also state that they would never vaccinate. (Orac has pointed this out many times in great insolent detail.)

But there are some parents who have bought into this notion and have reduced and/or delayed the number of vaccines their children receive in the hopes that they can strike a better balance of risk vs benefit than the experts have struck. And there are fringe doctors, like Dr. Jay Gordon, who promotes his own evidence-free alternate vaccine schedule, playing into the “too many, too soon” meme.

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31 responses so far

Apr 12 2010

The Anti-Vaccine Environmentalist

The anti-vaccine movement, as is probably typical for ideological movements, has natural enemies and allies. Once the notion that mercury in the form of thimerosal in vaccines might be responsible for neurodevelopmental disorders (it’s not) became popular in the anti-vaccine crowd, this made them natural allies with the “mercury-militia” – those who blame environmental mercury for a host of ills. The fact that some anti-vaccinationists seek to provide their children on the autism spectrum with unconventional biological treatments, based on their disproved “toxin” hypothesis, made them natural allies with the alternative medicine community. Both seek freedom from pesky regulation, and rail against the perceived deficiencies of science-based medicine.

Another ideological alliance is brewing – that between the anti-vaccine movement and extreme environmentalists. This post is not a commentary on environmentalism, and please do not take it as such – the purposes and claims of the two movements are quite distinct. But they share a common thread: distrust of scientific experts and government regulators who reassure the public that environmental exposures are safe.

Robert F. Kennedy Jr. has been the most prominent environmentalist to take up the anti-vaccine cause, in several articles and speeches. While he appears to be only a part-time anti-vaccinationist, his celebrity and street cred among environmentalists lend a great deal of weight to his paranoid musings about scientific fraud and government cover ups. It seems he wants to recapitulate the moral clarity that his uncles displayed in the 1960s, defending the little guy against abuses by the powerful and privileged. He is ready to see a conspiracy, and he wants to be the crusader for environmental justice – and if kids are the alleged victims, all the better. His article in the Huffington Post – “Attack on Mothers,” says it all.

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21 responses so far

Mar 16 2010

Autism Omnibus Hearings – Part II

I love a good sequel. Aliens, of course, was the best sequel ever – that rare event when the sequel is actually better than the original movie (of course, the series went down hill from there, like Star Trek it peaked with the second movie).

Last year we heard the results of the Autism Omnibus – a special court with three special masters set up to resolve about 5,000 cases before the vaccine court claiming that autism resulted from vaccines – either the MMR vaccine or thimerosal (a mercury-based preservative in some vaccines, but removed from most by 2002). In the US there is a Vaccine Injury Compensation Program (VICP) which bypasses the regular courts and awards compensation to those injured by vaccines, paid for by a small tax on each dose of vaccine given. The purpose is to rapidly compensate those who might have been injured (the threshold for evidence is quite low) and to encourage pharmaceutical companies to manufacture vaccines (the threat of suit would make it not viable otherwise).

Over 2008 the Autism Omnibus heard three cases that were presented as the test cases (presumably the best cases they could come up with) for the theory that the  MMR vaccine (with or without thimerosal from other vaccines – MMR never had thimerosal) caused or contributed to autism in some individuals. They ruled against all three cases, stating in very strong terms that there is no evidence to back up the claims of a link between MMR and autism. Judge Hasting wrote of one case – Cedillo:

Considering all of the evidence, I found that the petitioners have failed to demonstrate that thimerosal-containing vaccines can contribute to causing immune dysfunction, or that the MMR vaccine can contribute to causing either autism or gastrointestinal dysfunction. I further conclude that while Michelle Cedillo has tragically suffered from autism and other severe conditions, the petitioners have also failed to demonstrate that her vaccinations played any role at all in causing those problems.

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15 responses so far

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