Toxic tipping point: once government regulators and pharmaceutical companies knew that mercury in childhood vaccines might be responsible for an epidemic of autism, did they publicize their data and mount a recall? No. They were more concerned with protecting the national vaccine program—and shielding themselves from liability

IN AUGUST OF 2001, Rita Shreffler of Nixa, Missouri, sent her son's baby tooth to a lab. A year earlier, nine-year-old Andy had been diagnosed with Asperger's syndrome, a form of autism, and Shreffler had just read a report in the journal Medical Hypotheses suggesting that such neurological disorders might be the result of mercury poisoning associated with an additive in children's vaccines.

Wayne Middleton, of Middleton Microbiological & Environmental Testing Laboratory, was so astonished at Andy's results that he even used his own children's baby teeth as controls. Andy's tooth registered a mercury level of 3,040 parts per billion. By comparison, the Environmental Protection Agency's limit for mercury in drinking water is 2 ppb, and the limit for mercury content in waste going into a landfill is 200 ppb.

"Wayne asked me how on earth Andy could have been exposed to so much mercury," recalls Shreffler. "When I explained that a vaccine preservative called thimerosal had exposed babies to excessive levels of mercury, he said that couldn't be true because he used to work for a lab that made animal vaccines, and thimerosal had been discontinued in vaccines for cattle back in the early 1990s. He was sure it wouldn't be allowed in children's vaccines."

He was wrong.

The Battle Lines

DID THE USE OF A MERCURY preservative in vaccines directly contribute to the autism epidemic plaguing the country? And did federal health officials--fearful of liability facing their agencies and vaccine manufacturers, and loss of compliance with the federal vaccine program--put such concerns above the health of millions of infants? Are the recent studies discounting a link between thimerosal-containing vaccines (TCVs) and autism really rife with conflicts of interest and data manipulation? Or are the parents, researchers, and members of Congress who make such claims seeing conspiracies where none exist?

The stakes in this debate are high indeed. In 2002, an estimated 1 in 250 American children was diagnosed with autism, up from 1 in 500 in 2000, and 1 in 5,000 in the 1980s. If vaccine manufacturers and government agencies are found liable for neurological damage to millions of infants, TCV litigation could rival that of tobacco or asbestos. Currently, some 3,500 families of autistic children are slated to go before a special federal vaccine court--a step that Congress has required before they engage in any civil litigation, but one that will probably be just the first in a long legal battle.

The controversy began back in July 1999, when the American Academy of Pediatrics and federal health officials unexpectedly announced that thimerosal would be phased out of children's vaccines--a change, they insisted, that was purely precautionary. "The current levels of thimerosal will not hurt children," said then-AAP president Joel J. Alpert. "Reducing those levels will make safe vaccines even safer."

Prior to the AAP announcement, there had been no public outcry against TCVs. But there had been increasing concern about mercury in fish and other food, so much so that Rep. Frank Pallone (D-N.J.) authored a bill requiring the Food and Drag Administration to evaluate mercury levels in all food and drug products--including vaccines. This accounting unearthed a disturbing fact: Throughout the 1990s, as new TCVs were added to the list of a child's required shots, federal health officials had inadvertently nearly tripled the amount of mercury--a potent neurotoxin--being injected into some babies during a critical period for brain development. Astonishingly, as each new vaccine was added to the schedule, no one bothered to total up how many micrograms of mercury children would receive as a result. By 1999, a baby who received all recommended vaccines at her two-month checkup could be injected with up to 62.5 micrograms of mercury--118 times the EPA's limit for daily exposure. (These guidelines are based on methylmercury, while thimerosal contains ethylmercury; the difference regarding human toxicity is thus far unclear.) During the 1990s, when some 40 million children were vaccinated, the number of TCVs given to children nearly tripled, while autism rates inexplicably increased tenfold.

Though the public didn't know it, this discovery alarmed health officials. Consider a June 29, 1999, email sent by Peter Patriarca of the FDA, which licenses vaccines, to Martin Meyers, head of the CDC office that monitors vaccine safety and formulates immunization policy in concert with the AAP. Facing pressure from AAP vaccine expert Neal Halsey to assess and disclose the thimerosal problem, Patriarca said he feared the FDA would be criticized for being "'asleep at the switch' for decades by allowing a potentially hazardous compound to remain in many childhood vaccines and not forcing manufacturers to exclude it from new products." Noting that calculating the cumulative dose really involved nothing more complicated than ninth-grade math, Patriarca posed the questions he feared would be asked: "What took the FDA so long to do the calculations? Why didn't CDC and the advisory bodies do these calculations when they rapidly expanded the childhood immunization schedule?"

Transcripts of CDC meetings show that officials compounded this remarkable lapse in oversight with concerted efforts to minimize both the extent of the problem and any liability their agencies faced. "We are in a bad position from the standpoint of defending any lawsuits," noted one CDC adviser, "and I am concerned." Regulators chose not to act aggressively to reduce infants' exposure to thimerosal, and as a result TCVs mandated for infants remained on the U.S. market until November 2002. (The CDC and FDA refused Mother Jones' requests for interviews, as did vaccine makers, citing pending litigation.)

"You would think the CDC and FDA would be totally mobilized," says Rep. David Weldon (R-Fla.), "that they would be making rapid efforts to get mercury out of all the vaccines, bringing in independent scientists to study this, and really doing a very thorough investigation. But their response has been totally inadequate."

As a conservative and a physician, Weldon is an unlikely critic of either the vaccine program or of pharmaceutical companies. But he sat on the Committee on Government Reform, and when its then chairman, Pep. Dan Burton (R-Ind.), was prompted by his grandson's autism diagnosis to investigate the risks posed by mercury in vaccines, Weldon found himself listening to three years of testimony on the subject. Now, like many parents of autistic children and a growing number of scientists, he believes that exposure to thimerosal among infants born with a heightened sensitivity to mercury or an inability to excrete it could have contributed to the autism epidemic.

Dr. Weldon is also troubled by what he described in a November 2003 letter to CDC director Julie Gerberding as a "disturbing pattern" of collusion among vaccine-program officials, the pharmaceutical industry, and others with a vested interest in minimizing liability. Weldon specifically addressed a just-published and much-publicized Pediatrics article that analyzed CDC vaccine data and claimed there was no consistent link between TCVs and autism. Weldon's review of the study revealed the "appearance of selective use of data to make the associations ... disappear." He also noted that Pediatrics failed to mention that the study's author now works for a vaccine maker facing liability and instead identified him as still being a CDC employee, which "undermines this study further."

Weldon also asked that the CDC provide all its vaccine data to independent researchers, which thus far it has been unwilling to do. "If it is eventually determined that an entire generation of kids was essentially poisoned, a class-action suit against the federal government could be on the order of hundreds of billions of dollars, and so there's very good reason for them to try to cover this up," says Weldon. "And then when they appear as though they are covering it up, it makes you suspicious that it's all true."

Between the Cracks

ANYONE WHO RECALLS the stinging sensation of having a skinned knee painted with a reddish-orange antiseptic called Merthiolate has an intimate acquaintance with thimerosal, simply another name for the bacteria-killing compound developed by Eli Lilly in 1929. Early internal safety data on injections containing thimerosal were not encouraging. In 1935, for example, a researcher reported to Lilly that adverse reactions indicated that thimerosal was "unsatisfactory as a preservative for serum intended for use on dogs."