Following my posts about the introduction to The Truth About Vaccines and the first chapter of the book, on vaccines and autism, here is a post about Dr Richard Halvorsen’s chapter on mercury in vaccines.
Halvorsen begins by telling us of historical concerns about potential harms of thiomersal, a vaccine preservative that includes mercury (in the form of ethylmercury). He then refers to an internal memo at Merck that noted concern among regulatory bodies regarding thiomersal in vaccines. Next, he tells us that the US Environmental Protection Agency (EPA) reduced its recommended safe levels for intake of methylmercury – which is a related compound that is more dangerous than the form found in thiomersal. Note that, so far, Halvorsen has done nothing more than inform us that there has been concern about the potential for thiomersal to be harmful.
Before I continue, I would like to point out that the Institute of Medicine (IOM) examined the hypothesis that vaccines, specifically the measles-mumps-rubella (MMR) vaccine and thimerosal-containing vaccines, are causally associated with autism. They found that:
the body of epidemiological evidence favors rejection of a causal relationship between thimerosal-containing vaccines and autism. The committee further finds that potential biological mechanisms for vaccine-induced autism that have been generated to date are theoretical only. [Link.]
It is also worth noting that one of the reasons that concerns were raised about a link between mercury-containing vaccines and autism was that autism rates were alleged to have increased following the introduction of mercury-containing vaccines. Given that in January 2003 the last children’s vaccines that used thimerosal as a preservative expired, and that the Prevalence of Parent-Reported Diagnosis of Autism Spectrum Disorder Among Children in the US, 2007 was higher than previous US estimates, it seems that concerns about mercury-containing vaccines and autism were unfounded.
The explanation given by the authors of the study in the latter link is that “more inclusive survey questions, increased population awareness, and improved screening and identification by providers” may partly explain the finding that prevalence of autism had risen. Changing diagnostic criteria and increased awareness are among the likely reasons for the increase in diagnoses of autism. MMR or mercury-containing vaccines are not. [In fact, the prevalence of autism in both children and adults is estimated to be roughly 1 in 100 – as the Adult Psychiatric Morbidity Survey (APMS) 2007 states: “Using the recommended threshold of a score of 10 or more on the Autism Diagnostic Observation Schedule, 1.0 per cent of the adult population had ASD. Published childhood population studies show the prevalence rate among children is also approximately 1.0 per cent.” There has not been an “epidemic of autism” in recent years, as is sometimes claimed by those opposed to vaccination.]
Anyway, enough of this information about thiomersal – let’s get back to Halvorsen’s scaremongering.
On page 24 of the book, Halvorsen tells us that the Food Standards Agency (FSA) in 2003 issued safety guidelines concerning the levels of methyl-mercury (note: not ethylmercury) in fish and that the FSA advised pregnant and breast-feeding women to be cautious with their intake of mercury. The FSA advice for the rest of the population is that “We should be eating at least two portions of fish a week including one of oily fish” and that men and boys, and “women who won’t have a baby in the future” should eat no more than four portions of oily fish per week. The advice for women who are trying to conceive or who are pregnant is to eat no more than two portions of oily fish per week and to avoid shark, swordfish, and marlin.
While emphasising that the FSA have urged women to be cautious about mercury-containing fish, Halvorsen fails to inform us of recommendations made by the FSA – essentially that pregnant women and those hoping to conceive should eat half the amount of oily fish than is recommended for others, and avoid certain large fish. This emphasis on caution and the avoidance of harm from mercury-containing fish and the failure to report on the benefits of (again, mercury-containing) fish is mirrored in Halvorsen’s portrayal of mercury-containing vaccines. [FSA page on fish and shellfish.]
Here, meanwhile, is a report on a study that found that mercury levels in children with autism and those developing typically are the same. And here is a review: Fish consumption, methylmercury and child neurodevelopment.
Halvorsen claims, on page 26, that “most experts agree that [ethylmercury and methylmercury] are similarly toxic” and cites a single paper [PDF] to support this claim. He then claims that ethylmercury “has been linked to autism and other developmental disorders in scientific studies and by doctors”, citing (among others) S Bernard, B Rimland, and the Geiers. I cannot find the full text of the Geier paper – or, weirdly, any papers that cite it.
I did find, however, A Critical Review of Published Original Data, in which the authors discuss other papers written by the Geiers on mercury in vaccines. They report that the Geiers’ report of “an “instantaneous excess” of mercury in vaccines“, and the calculations that led to this conclusion:
are a misinterpretation of the EPA and FDA guidelines, which define their reference dose as “an estimate of daily exposure to the human population (including sensitive subpopulations) that is likely to be without a risk of adverse effects when experienced over a lifetime.”
And here we get to the meat of the claims that mercury in vaccines is harmful – they are based on misinterpretations of guidelines. The recommendations for exposure to mercury that are so often cited by those opposed to vaccination are based on lifetime exposure. Not on exposure on a single day (for example, the day that a vaccine is administered).
For more on the Geiers, see here, here, and here. For more on thiomersal / thimerosal and autism, see here, here, and here (note: a study by the Geiers is criticised on page 9 of this PDF, for inadequate description of methodology and unjustified conclusions). See here for Mercury Levels in Newborns and Infants After Receipt of Thimerosal-Containing Vaccines, and see here for a paper which notes that mercury clears from the infant body faster than from the adult body.
Summary of the chapter
Perhaps the most interesting element of this chapter is the section of related reference notes at the back of the book. Halvorsen cites memos; emails, newspaper reports; unpublished calculations that he has performed himself; statements from the FSA regarding methylmercury (not ethylmercury) and fish consumption; and single papers that support his point of view. He does not tend to refer to papers that do not support his view – except to point out that studies cited in support of the safety of thiomersal / thimerosal have been criticised by scientists such as the Geiers. Nor does he address the criticisms of the papers he does cite. There is referenciness, but there is not substantiation or justification for Halvorsen’s assertions or scaremongering.
Perhaps realising this, Halvorsen seems to back off somewhat from the claim that mercury in vaccines causes autism. On page 30, he writes that “it is unlikely that mercury in vaccines is causing most cases of autism, but may still have caused autism in a susceptible minority” – but does not even attempt to justify the claim that mercury-containing vaccines may have caused autism in a susceptible minority. Maybe because he cannot do so.