Vaccines, Mercury Exposure and Autism

Over the past 14 years, the estimated incidence of autism in the U.S. rose from about one in every 2,500 children to one in 166 – a fifteenfold increase. This steep rise coincided with the sharp increase in the number of vaccines given children, most of which were preserved in thimerosal. Thimerosal contains mercury, a potent neurotoxin.

The case linking the autism epidemic to mercury-preserved childhood vaccines has become one of the most contentious issues in environmental medicine. It has pitted a small but vocal coalition of affected parents, environmental groups, epidemiologists, trial lawyers, and even some conservative Republicans against the entire U.S. scientific and pediatric establishment, starting with the Centers for Disease Control and Food and Drug Administration and extending to the drug industry and even some of its more vocal critics like Rep. Henry Waxman, the liberal Democratic of California.

The vaccine manufacturers began phasing out thimerosal in the late 1990s after the first alarm bells went off. But as late last year, the industry – with a helping hand from the Centers for Disease Control and the Food and Drug Administration – continued selling stockpiles to the developing world. The case linking vaccines to autism received a powerful boost yesterday from Robert Kennedy Jr. on Salon.com (it’s very long, and you’ll have to sit through a Microsoft commercial to read it online).

Kennedy, best known for his environmental activism, wrote that “I devoted time to study this issue because I believe that this is a moral crisis that must be addressed. If, as the evidence suggests, our public-health authorities knowingly allowed the pharmaceutical industry to poison an entire generation of American children, their actions arguably constitute one of the biggest scandals in the annals of American medicine.”

I spent a few weeks earlier this year reviewing some of the evidence linking thimerosal to autism. I spoke with a number of leading environmental health epidemiologists, many of whom remain skeptical. How can one tease out early childhood exposures to mercury in vaccines from other exposures like power plant pollution, not to mention the swelling sea of neurotoxic chemicals that persist in the environment and cause similar disorders?

Indeed, some scientists argue that the rise in autism is an artifact of better diagnosis, not an actual increase in disease. But people who work in the schools and have been inundated with these children scoff at such assertions. But there is a way to tell. Because of the phase-out, most American children vaccinated in this decade have not received the same high levels of mercury as those vaccinated between 1989 and 2001. If there is a link, it should start showing up soon in sharply falling autism rates.

What’s needed now is an accurate, long-term epidemiological study of America’s children – one sufficiently large enough to gauge the incidence of diseases like autism that only affect a small percentage of the population. Fortunately, such a study has been in the works for five years and is ready to be launched. Unfortunately, the Bush administration is about to back out of its commitment to fund it.

I’ll write about the National Children’s Study – and why people should begin putting pressure on Congress and the National Institutes of Health to fund it – in my next posting.

Posted by gooznews at June 17, 2005 08:07 AM