-BOOK REVIEW-

Veteran New York Times science reporter David Kirby's new best- seller tackles a highly charged issue: whether or not the vaccine preservative thimerosal, which is 50 percent mercury, is a key culprit in rapidly rising rates of autism and related neurodevelopmental disorders.

While Evidence of Harm takes no sides in the controversy, readers will be disturbed by Kirby's unsparing portrayal of the failure of government agencies and drug companies to evaluate the potential health risks of thimerosal-even as the number of childhood vaccines containing the substance soared. (Many children were exposed through vaccines to more than 100 times the amount of mercury the Environmental Protection Agency's safety threshold allowed.) Moreover, both medical professionals and parents will come away with a sense that the government "watchdog" agencies responsible for protecting children's health are too often focused on protecting the bottom line of pharmaceutical companies instead.

Kirby concludes that his research uncovered substantial evidence implicating thimerosal as a cause of the current autism epidemic, but that "evidence of harm is not proof of harm." One form such proof could take, he says, would be a drop in autism rates now that thimerosal is being phased out of vaccines-a trend that is now being seen in California, where the Department of Developmental Disabilities is reporting significant declines in new cases of autism after a steep and consistent rise for more than a decade.

Kirby's book is an important read for parents and professionals alike. With rates of ADHD, depression, and learning disabilities rising rapidly along with rates of autism, Evidence of Harm should be a wake-up call for America to demand more extensive and honest research-and more accountability from public and private agencies-when it comes to the the exposure of our children to toxins that could alter their brains and behavior for a lifetime.

Mercury is a recognized neurotoxin that can destroy cells in key centers of the brain and nervous system. It is especially hazardous to fetuses and small infants, whose vital organs are still developing. Mercury is known to halt cell division and migration within the forming brain, and has been shown to bind to DNA, interrupting chromosomal reproduction and blocking several essential proteins.

Sensitivity to mercury ranged widely among individuals. In fetuses and developing infants, there was a ten thousand-fold increase in sensitivity as compared to adults. What's more, boys were four times more likely to be mercury sensitive than girls-the same ratio found in cases of autism. It was also roughly the same ratio for ADD, tics, speech delay, and most of the other neurological developmental disorders associated with increased thimerosal exposure by the CDC itself.

The Mad Hatter in Alice in Wonderland was believed to be modeled on a syndrome resulting from occupational exposure to mercury vapor used in millinery, called "Mad Hatter's disease." The affliction struck a certain percentage of hatmakers in centuries past. People with Mad Hatter's disease suffered from depression, sluggishness, acute anxiety, and irrational fears. They grew nervous and timid. They blushed readily, were uncomfortable in social situations, and sought to avoid people. "Mad Hatters" were easily upset, had trouble with movement and coordination, and were prone to agitation, irritability, and aggression.

(T)he thimerosal debate has compelled the scientific community, however reluctantly, to consider an environmental component to [autism], rather than looking for a purely genetic explanation. Autism, by most accounts, is epidemic. And there is no such thing as a genetic epidemic.

For attention deficit disorder, [researchers] found a statistically significant, dose-dependent response for exposure at six months of age. The increased relative risk for each microgram of ethylmercury was 1.006-or 0.6 percent. Therefore, a child who received 62.5 micrograms by six months of age was 30 percent more likely (RR 1:30) to develop ADD than a child who received 12.5 micrograms.

If thimerosal is one day proven to be a contributing factor to autism, and if U.S.-made vaccines containing the preservative are now being supplied to infants the world over, the scope of this potential tragedy becomes almost unthinkable.

Related Article: [2005, Vol. 11]