The vaccine preservative Thimerosal is not linked with autism, a new study reports. The data also suggest that the dilettante "scientist" Robert F. Kennedy, Jr. should perhaps go back to practicing law and stop exploiting parental fear and suffering for his own political agenda.
Despite an absence of intriguing, let alone compelling, evidence that mercury-containing Thimerosal was associated with autism, vaccine makers voluntarily began removing Thimerosal from their products in 1999 - providing a perfect opportunity to study whether the removal (and, therefore, Thimerosal) had any effect on autism rates.
So using data reported to the California Department of Development Services from 1995 to 2007, researchers from the California Department of Health compared the prevalence of autism with exposure to Thimerosal. Their results were published this week in the Archives of General Psychiatry (Jan. 2008).
The data showed that the prevalence of autism for children at each year from 3 to 12 years increased throughout the study period -- even after 2000 when Thimerosal began disappearing from vaccines. From 1999 to 2004, average exposure to Thimerosal among infants and 2-year olds was reduced by more than 90 percent and 84 percent, respectively – yet reported cases of autism continued to increase in unabated fashion.
A classic test in epidemiological study is to observe what happens to the rate of disease when the suspected agent is removed. When Thimerosal was removed, the rate of disease was unaffected.
Ironically, it has taken the removal of Thimerosal to vindicate it. This result is not unexpected since there has never been any reason to believe that Thimerosal was a causal factor in autism spectrum disorders, which have reportedly increased in recent decades.
Use of Thimerosal began in the 1930s in response to tragedies such as the January 1928 deaths of 11 of 21 children given a diphtheria vaccine inadvertently contaminated with staphylococci.
Thimerosal was then used without incident for more than 65 years before the panic began in 1998 with the publication of a paper in British medical journal The Lancet reporting autistic regression and diarrhea among a small number of patients following administration of the measles-mumps-rubella (MMR) vaccination.
As retold in the current issue of the American Journal of Public Health, the Internet enabled the controversial report to cross the Atlantic and spawn a coalition comprised of parents of autistic children and groups opposed to compulsory vaccination. Political muscle was soon added when Rep. Dan Burton (R-IN), whose grandchild had been diagnosed with autism, began a series of congressional hearings.
But despite the emergence of the anti-Thimerosal movement as a cause celebre , there has never been a single credible study implicating Thimerosal in any way with autism. The new California Department of Health study should be the end of the controversy.
That brings us to Kennedy who seems to revel in his profound scientific ignorance.
In a June 20, 2005 Rolling Stone article entitled "Deadly Immunity ", he wrote, "It was only after reading the [testimony of a Centers for Disease Control epidemiologist at a closed door government meeting], studying the leading scientific research and talking with many of the nation’s pre-eminent authorities on mercury that I became convinced that the link between Thimerosal and the epidemic of childhood neurological disorders is real."
Kennedy’s article had so many significant inaccuracies that Rolling Stone was forced to append to it five paragraphs of corrections.
Undeterred, two years later Kennedy wrote an article entitled "Attack on Mothers ."
Recounting the onset of autism in a 2-year old, Kennedy wrote, "After hearing that story a couple dozen times, a rational person might do some more investigation. That’s when one encounters the overwhelming science - hundreds of research studies from dozens of countries showing the undeniable connection between mercury and Thimerosal and a wide range of neurological illnesses." Kennedy went on to accuse the Centers for Disease Control and Prevention and the pharmaceutical industry of "ginning up" studies "designed to disguise the link between autism and Thimerosal."
So Mr. Kennedy, is the California Department of Health also a member of the vast Thimerosal conspiracy?
There may be some ideological overlap between Kennedy’s anti-Thimerosal rantings and his jihad against coal-fired electric plants whose emissions include small amounts of mercury.
He recently blogged  about the "calamitous externalized costs" of coal, including "global warming…dead forests and sterilized lakes from acid rain, poisoned fisheries in 49 states and children with damaged brains and crippled health from mercury emissions, millions of asthma attacks and lost work days and thousands dead annually from ozone and particulates."
It’s quite possible that Kennedy chooses to exploit the Thimerosal-autism controversy in order to broaden his base of support for his anti-coal/global warming agenda. Anti-Thimerosal parents groups have proven to be extremely passionate about their cause and they would be a formidable force were they to campaign against coal-fired electricity with the same zeal as they did with Thimerosal.
Though use of Thimerosal has for the most part ended, its vindication is not merely of academic interest. It should serve as yet another data point against Kennedy and others who foment panic and urge a rush-to-action based on flimsy facts and misdirected anger.