A familiar chorus of cacophony is rising up in response to the new Centers for Disease Control and Prevention study of thimerosal, the mercury-based preservative and neurotoxin used in some vaccines. Published in the New England Journal of Medicine, the study of more than 1,000 7-to-10-year-old children who received dosages of thimerosal as part of their infant vaccinations conducted a series of neuropsychological tests looking at things like attention span, fine-motor skills and IQ. Although the researchers found little or no effects of the chemical on the children's neurological health (the statistically significant effects were evenly split between positive and negative traits), the study has become another lightning rod for the debate surrounding autism and vaccinations.
The anti-vaccine activists (including, at one point, Robert F. Kennedy Jr., who wrote about the topic for Salon and Rolling Stone) have been quick to discount the study's findings, though originally some of them, including SafeMinds' Sallie Bernard, helped plan it. Critics now point to the study's limitations: that the researchers didn't adjust for birth weight (smaller babies would mean exposure to relatively higher doses of the chemical) or that 70 percent of the families invited to participate in the study declined (presumably creating a selection bias against families with impaired kids). Other critics have accused the researchers of bias, since some have consulted for vaccine companies.
The other side -- including most of the mainstream press and the scientific community -- throws this study on top of a mountain of research that has concluded that there's little connection between the rising rates of autism and vaccinations. The anti-vaccine crowd simply won't listen to reason, they say.
After nearly a decade of following this story -- reading anti-vaccine books and stuttering through CDC research -- I find that the debate still gets under my skin. I don't have the technical expertise to analyze the research myself, so I must take everyone's word at face value. In the end, I threw my lot in with mainstream science and vaccinated my kids, but not without talking to my nurse-midwife, who had read some of the studies yet still delayed her own child's vaccinations.
But what's troubling for me in this maelstrom of emotional accusations and technical arguments about statistics is that both sides seem so utterly disdainful of the other. The fearful parents are dubbed a "mercury militia." The scientists on the other side are likened to Philip Morris lab rats discovering that cigarettes don't cause lung cancer. When discussion around children's health gets this nasty and inflammatory, aren't we losing sight of what's really at stake?