Child-vaccine preservative prompts surge in mercury-poisoning claims.

Autism. Autisim Spectrum Disorder. Neurological injury. Developmental delay. These are words that parents of young children dread hearing at a routine pediatric examination.

At best, a diagnosis of neurodevelopmental impairment means months or years of doctor visits--most often for physical, occupational, or speech therapy. At worst, as in cases of profound autism, the child spends a lifetime in a devastatingly detached world: unable to communicate with others; engaging in self-destructive head-banging or other odd behavior like rocking, arm-flapping, or toe-walking; and tortured by a host of related immune system and digestive disorders, including lack of appetite and chronic diarrhea.

Most parents have nothing to fear--statistics indicate that a child born today will develop normally into adulthood.

Yet the rates of autism and other neurological disorders among young children have sky-rocketed in the past decade. And a growing number of outraged and determined parents--backed by a host of medical experts, trial lawyers, and at least one member of Congress--say they know why: The children have been poisoned with mercury.

That claim is the core of lawsuits filed in the past year against several of the world's largest pharmaceutical companies. The complaints allege that thimerosal, a mercury-laden preservative used widely in childhood vaccines during the 1990s, is responsible for neurological injuries suffered by thousands of children who were vaccinated in that decade. Many of the complaints also claim that even those children who appear healthy now--but nonetheless received injections containing thimerosal--are at increased risk of developing as-yet-unidentified illnesses and disorders.

The drug companies counter that there is no reliable scientific evidence linking thimerosal to autism or other neurodevelopmental disorders. They cite a 2001 report from the National Academy of Sciences' Institute of Medicine (IOM) that concluded there is insufficient evidence to prove that thimerosal-laced vaccines cause brain or nerve damage in children.

Trial lawyers representing the children and their parents concede that no single study to date proves the theory, but they say the circumstantial evidence is substantial and strong.

"I think the evidence is clear when you compare the rise in autism rates with the time span that the shots containing thimerosal were given and the number of shots the children received during that time," said Derric Crowther, an Atlanta-based attorney whose firm is part of a nationwide coalition of more than a dozen that have filed thimerosal cases.

Autism was once considered a rare disorder, affecting about 1 child in 10,000. But since 1990, the number of diagnoses of pediatric cases has soared by as much as 500 percent, according to complaints filed by plaintiffs. In some states, like California and New Jersey, the rate of autism among children under 10 is 1 in 150. It is the third most common childhood developmental disorder; only mental retardation and cerebral palsy occur more.

Thimerosal, which is 49.6 percent mercury by weight, has been used as an antibacterial and antifungal agent in vaccines since the 1930s. That use was fairly limited until the 1990s, said Crowther, when two things happened that greatly increased children's exposure to the preservative.

First, to cut costs, manufacturers began producing more multidose vials of childhood vaccines. Unlike the more expensive single-dose vials, which are discarded once used and therefore need no preservative, multidose vials contain enough vaccine to innoculate several children. Thimerosal was added to these vials to inhibit contamination of the vaccine once a seal was broken to draw the first dose.

Second, children began receiving more vaccinations at earlier ages. By 1990, infants and toddlers were already receiving injections to protect against diphtheria, tetanus, pertussis, mumps, measles, and rubella. Then two new vaccines were added to the list of routine childhood immunizations: hepatitis B and Hib, which protects against the potentially fatal hemophilus influenza type B virus.

Because many of these vaccines have to be given in several doses, months apart, a child typically received more than 20 shots by the age of three--when the first symptoms of autism often emerge.

Despite mercury's long-established reputation as a human toxin, its use in vaccines did not get much notice until 1999. After conducting a review of biologic products containing mercury, required by a 1997 law, the Food and Drug Administration (FDA) issued a statement that infants who received thimerosal-laced vaccines "may be exposed to more mercury than recommended by federal guidelines for total mercury exposure."

"At two months, my son received 62.5 micrograms (mcg) of mercury, which was 125 times the EPA's [Environmental Protection Agency's] allowable limit of 0.5 micrograms," said Lyn Redwood, the mother of an autistic boy. Redwood is president of Safe Minds (Sensible Action for Ending Mercury-Induced Neurological Disorders), a nonprofit organization she founded in 2000 to investigate and expose harms caused by mercury in medical products.

In the wake of the FDA's announcement, the American Academy of Pediatrics and the U.S. Public Health Service issued a joint statement alerting clinicians and the public to the concern about thimerosal. Shortly after that, the FDA asked vaccine manufacturers to eliminate thimerosal from vaccines. It is no longer being added, Redwood said, but because there was no recall, many vials containing thimerosal remain on doctors' shelves.

The heat is on

Plaintiffs have filed dozens of lawsuits against vaccine makers and others in thimerosal's distribution chain, and more suits are on the way, said Clair Campbell, a lawyer in Charlotte, North Carolina. Her firm is working with a group of about 25 firms, separate from Crowther's group, representing thimerosal victims.

Both Campbell and Crowther said their firms are handling cases individually, not as class actions. Redwood's case is one of dozens Crowther's firm has filed. Other lawyers are seeking class action certification for the estimated 30 million children who have been exposed to thimerosal.

And Michael Williams, a Portland, Oregon, lawyer and cochair of ATLA's Vaccine Injury Litigation Group, heads yet another coalition, the Mercury Vaccine Alliance. It comprises about 35 plaintiff firms that so far have filed class actions in 11 states--California, Connecticut, Maine, Maryland, Massachusetts, New Hampshire, Oregon, Pennsylvania, Virginia, Washington, and West Virginia. (See Mead v. Aventis Pasteur, Inc., No. 0107-07137 (Wash., Multnomah County Cir. Ct. filed Oct. 2, 2001).)

Among the suits' claims are products liability, fraud, failure to warn, and breach of warranty. Some plaintiffs are seeking damages related to the neurodevelopmental injuries they claim were caused by thimerosal; others have added demands for medical monitoring of asymptomatic children. A series of class actions brought by the mercury alliance seeks to force the pharmaceutical industry to fund research that is needed to prove once and for all whether thimerosal is related to the surge in neurodevelopmental disorders among young children.

Statistics and science

Representatives of defendant vaccine makers contacted for this story either declined comment, citing the pending litigation, or did not return calls. But so far, the nation's largest medical and scientific organizations--including the FDA, the National Institutes of Health, the American Academy of Pediatrics, and the Centers for Disease Control and Prevention (CDC)--are on their side. The groups' official position mirrors the IOM's 2001 report: There is no evidence to suggest that thimerosal in vaccines causes brain or nerve disorders in children or adults.

Stephanie Cave, a pediatrician in Baton Rouge, Louisiana, who treats more than 1,800 autistic children, disagrees. Aside from the correlation between the rates of autism and the use of thimerosal, she said, plenty of evidence supports a connection.

Perhaps the strongest proof, she said, is the improvement in her young patients who are treated for heavy metal toxicity: "We started adding metal retrieval in treatment in late 1999, and the children started responding quickly." The younger a child was detoxified, the better. "Two- to five-year-old children responded very well. At least 50 percent of those children are 80 to 90 percent back to normal after treatment," Cave said.

She also pointed to striking similarities between the characteristics of autism disorders and those of chronic mercury poisoning, including lack of eye contact, repetitive behaviors, social withdrawal, loss of speech, and episodes of hysteria. "It is very possible that autism has always been [caused by] mercury poisoning," Cave said.

Redwood said that when she first read about those similarities, "I stopped in my tracks. That's exactly what happened to my son. He was walking and talking on schedule, meeting all the developmental milestones, and then he suddenly lost speech and started avoiding eye contact."

This regression in development, which is common among children diagnosed with autism and related disorders, is yet more evidence of thimerosal's role in the conditions' increase, Cave said. "What we're seeing now is regressive autism. A child develops normally, and then after a series of injections, begins to regress. We're not seeing signs at birth like we did in the 1930s" before thimerosal appeared, she said.

Plaintiffs must rely on circumstantial evidence, Redwood said, because published studies on thimerosal's toxicity simply don't exist. "I'm not surprised that when the IOM looked at this they found no evidence to prove or disprove the link, because it's so new. It's appalling that toxicity studies were not required when [thimerosal] was approved."

Last year, in hopes of uncovering research that would prove the link, Redwood's group submitted a Freedom of Information request to the CDC. In its response, the agency included a preliminary draft of a report stating that children who had received 62.5 mcg of mercury in vaccinations before three months were 2.48 times more likely to become autistic.

"I've been told by lawyers that anything over two times would be enough to imply cause and effect in court," Redwood said. But, she added, before the report was released, the CDC "diluted" the results by adding another 34,000 children to the study. The final report states that thimerosal-exposed babies are only 1.69 times more likely to develop autism. (Verstraeten Thomas, Centers for Disease Control and Prevention, Risk of Neurologic and Renal Impairment Associated with Thimerosal-Containing Vaccine, June 2000.)

"Nineteen thousand of the children added in later were under age one. You cannot diagnose children with speech or language delay before they have speech," Redwood said.

So why aren't all children who received thimerosal-laced vaccinations neurodevelopmentally impaired?

"It depends on genetic susceptibilities," said Boyd Haley, a mercury toxicity expert who heads the Department of Chemistry at the University of Kentucky. Some children can excrete metals better than others, depending on their genetic makeup, he said.

Haley's theory is supported by recent research focusing on mercury levels in baby hair. The baby hair of children who were exposed to mercury but appeared healthy had mercury levels between 15 and 20 parts per million (ppm). Hair samples from autistic children with similar mercury exposures contained mercury levels of only 1 ppm, Haley said.

In autistic children, the mercury does not get into the hair: "Instead, it collects and stays in the brain."

Haley said he has conducted experiments on human brain tissue that may end the debate. "Mercury is the most toxic metal known to man, and thimerosal is more toxic than straight mercury. It is extremely inhibitory to enzymes in human brain tissue. It inhibits the same proteins that mercury does, and additional ones, and it does it very effectively."

When Haley added thimerosal to samples of brain tissue, he said, "it slowly killed all the cells over a 24-hour period."

The government is also feeling the heat. As chairman of the House Committee on Government Reform, Rep. Dan Burton (R-Ind.) has conducted several hearings regarding the use of thimerosal in children's vaccines. Burton has a personal interest in the issue--he is the grandparent of an autistic child.

Burton has criticized the government's response to what he has called an "epidemic" of autism. At a June hearing, his committee grilled representatives from the CDC and the FDA regarding what the government knew about thimerosal and when.

"He didn't get any good answers," Redwood said, adding that government health agencies have been questioning the safety of thimerosal for years. "Did you know that it was taken out of dog vaccines in 1992? Or that the FDA banned its use in over-the-counter drugs in 1998?"

Plaintiffs have far more questions than answers. But they hope that as the lawsuits proceed, answers will be found and will confirm the suspected link.

"All fingers are pointing at thimerosal," Haley said. "Have we proven it yet? No."

But he's convinced it is just a matter of time. Until then, the statistics, at least, seem to be in the plaintiffs' favor.