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Autism, Mercury and the Anti-Merc Activists: Whose Conflicts?


The Institute of Medicine held a workshop this past week to examine research into the "environmental" causes of autism. It was a time for discussion among scientists pursuing possible links, and a chance for some of the autism "advocacy" community to press their research priorities on government and academic scientists. No less a bigwig than Alan Leshner, president of the AAAS and editor of Science, presided over the meeting, also attended by the directors of two of the National Institutes of Health.

The opinions of the parents of autistics, especially angry parents, occupy pride of place in our Oprah-fied public culture. Ignore them at your own peril. This is not an entirely bad thing. But there's a weird disparity between what's expected of the scientists and advocates in a setting like this.

There has been increasing public scrutiny of scientific conflicts of interest in recent years, no doubt a good thing. In the scientific culture, scientists are expected to acknowledge biases. In the "comments" section of their papers, for example, most scientists are in the habit of playing the devil's advocate by explaining how their results may have been skewed by the structure of their data or data collection; this is a recognition of the fact that many a scientific result can't be reproduced. Scientists are also obliged by most journals to describe any financial or relational bias that may impact the work, such as funding from a pharmaceutical company.

Public advocates have no such demands on them, and that was what was disturbing about the IOM workshop. Many of the scientists in this field and at the workshop table were drawn into it by the fact that they have autistic-spectrum children; that's a bias, of sorts, but it's also a strong motivation to find real causes and treatments of the disorder. But there were others at the meeting who were there simply to further pester the government and scientific community about their own pet theory for autism, which is that it was caused by toxins, particularly the mercury-based preservative thimerosal. The demeanor of people who buy this theory ranges from ranting and profane to reasonable. At the table last week were three groups--Autism Speaks, SafeMinds and the National Autism Association. As someone who entered the debate about this theory, in 2002, with an open mind, but h as come to the strong conclusion that there is no basis for blaming vaccines for an "epidemic" that may not even exist, I find some of the individuals in these groups, especially in SafeMinds, to be disingenuous. They are playing at scientific seriousness while refusing to acknowledge the data.

Study after study has shown no link between thimerosal and autism. The rates of autism continue to grow in cohorts of children who received no thimerosal-containing vaccines.

None of this makes an impact on some SafeMinds activists, who continue to insist that there is an epidemic of autism caused by mercury. In the face of the data, they blame the continuing rates on the poisoning of pregnant women with thimerosal-containing flu shots (although only something like 10 percent of pregnant women get this shot) and flu vaccination of toddlers (according to a 2004 NHIS immunization survey, only 18% of children 6--23 months got one or more flu shots).
If thimerosal was truly the cause of a huge upswing in autism beginning in the 1990s, we'd have seen the rates of new cases plummet since the substance was removed from the Hep B, HiB and DTP shots starting in 1999 (by early 2002, according to an informal CDC spot check of 150,000 doses of these vaccines at 447 provider sites in 25 states, 1.9 percent contained thimerosal). To make this crystal clear:
1950 --- ~ 1992: 80-90 percent of U.S. children get 3 DTP shots with thimerosal by age 6 months
~1993 -- 1999: 80-90 percent of U.S. children get 9 thimerosal-containing shots by 6 months of age
~2000 -- present: 20 percent of U.S. children get 1-2 flu shots (many of which contain thimerosal) between the ages of 6 and 23 months.

No one can be sure there hasn't been some increase in autism in the last couple of decades, but we can be sure that it isn't the huge, 10-fold increase that people like SafeMinds' Mark Blaxill are touting. And one thing is absolutely clear: thimerosal-containing vaccines are not responsible for an increase in autism.

Many of the people in the "mercury" camp (including SafeMinds' Lyn Redwood, and NAA's Laura Bono, both participants in the IOM workshop) are or were involved in lawsuits charging that their children were made autistic by mercury. And as Blaxill himself has pointed out (for example in a 2005 meeting at the CDC), you don't have to have a financial conflict of interest to cling stubbornly to a flawed position. It's enough to have too much professional pride, or to belong to a community of belief that will heckle or ostracize you if you step out of line (Blaxill, at the time, was talking about what he perceived as the pediatrics community's unwillingness to face the fact that it had been poisoning kids for years).

After you've spent years shouting at the government, participating in flawed Congressional hearings, writing junky "investigational" books and reports, ginning up gigantic legal claims that cost the courts, the public, and the drug companies hundreds of millions of dollars, and spreading unfounded slander against government scientists on the Web, it's pretty darn hard to step back and say, "Whoops, I was wrong." I just wish I could find someone--anyone--willing to do that.

We demand a lot of our government scientists and public health officials--and we should. But responsibility isn't only a government obligation.