Both camps in thimerosal issue find more evidence

When the Southeast Missourian published its first stories on a vaccine preservative called thimerosal a year ago, the theory that mercury in vaccines may be the cause, or at least related to the cause of autism, was just beginning to catch the attention of lawmakers.

For the first time, state and national legislators were sponsoring bills that would ban mercury from vaccines.

Although the removal of thimerosal from childhood vaccines began in 1999, a growing group of parents were gathering data and scientific studies that supported their claim that the rising autism rates and the corresponding increase in the vaccine schedule in the 1990s was not a coincidence.

A year after the Southeast Missourian published its first stories about thimerosal, we find that the theory hasn't died. In fact, the national attention has increased dramatically in recent months. NBC dedicated a week to autism on the "Today Show," which included reports about the controversy.

Likewise, national talk show host Don Imus has dedicated serious time to the topic. A new book, called "Evidence of Harm" by journalist David Kirby, is in its fourth printing, the author says.

Others camps, including top officials with the country's leading health agencies like the Centers for Disease Control and Prevention and the Institute of Medicine, say studies have shown that there is no association and that the thimerosal issue is being pushed by emotional parents who are bent on placing the blame of their children's condition on vaccines.

In Kirby's book, he notes that no employee at the Food and Drug Administration, the CDC or the American Academy of Pediatrics would agree to be interviewed for the book.

'Old news' to CDC

"The CDC has issued a two-page statement which I thought was very gingerly worded," said Kirby, who cited hundreds of studies, reports and correspondence in an index in the back of his book. "I appreciate the fact it was not negative in tone or personal. They're trying to say it's old news, but it's new news to most people."

Evidence on both sides of the debate has surfaced since last April.

The news started when a committee from the Institute of Medicine of the National Institutes of Health was charged with looking into the issue by the CDC.

In May 2004, the Institute of Medicine panel, based on five large epidemiological studies, stated there was no evidence suggesting that thimerosal was a threat to the general population and that there was no evidence of a link between vaccines and autism.

Critics of the Institute of Medicine panel's findings claimed the studies were based on complicated statistical formulas instead of under-the-microscope science. Detractors said statistics can be, and perhaps were, skewed to protect the interests of pharmaceutical companies and the vaccine program itself. They also questioned the study's methods and said the report, while taking statistical data from the overall population, did nothing to address the theory that only genetically susceptible children are at risk with thimerosal.

In Kirby's book, McCormick, who chaired the Institute of Medicine panel, said laboratory science can be manipulated just like epidemiology. She also said the panel was specifically picked to avoid conflicts of interest with pharmaceutical companies.

Experiments in mice

Dr. Steven Goodman, who was a member of the Institute of Medicine panel, told a Los Angeles Times reporter the study was "a tantalizing little piece of evidence that requires a lot more work" to overturn "tremendous amount of human work that doesn't find a clue of connection."

A few months after that, Dr. Jill James, a research scientist with the University of Arkansas, reported that autistic children have a severe deficiency in glutathione, which acts as the body's detoxifier. The report showed that autistic children have 133 percent more "inactive" glutathione in their bodies than healthy children and 68 percent less "active" glutathione.

Ethyl mercury, some studies have suggested, is too large of a compound to pass through the blood-brain barrier and cause neurological damage. Many, including some scientists who support the association with autism, say ethyl mercury is also less toxic than its cousin.

According to a recent experiment done on monkeys by Dr. Thomas Burbacher of the University of Washington, ethyl mercury is excreted faster than methyl mercury, making it, in one way, less toxic. However, the ethyl mercury that is not excreted changes quickly into an inorganic and more toxic form. Once that form reaches the brain, it gets "trapped" and prohibits certain neurons from growing properly.

A study on thimerosal and pain was released in July 2004 from South Korea. The study suggests that thimerosal interferes with pain sensors, which would, theorists say, explain why many autistic children don't feel pain.

According to the Times, the memo said that 6-month-old children who received their shots on schedule would get a mercury dose up to 87 times higher than guidelines for the maximum daily consumption of mercury from fish.

"When viewed in this way, the mercury load appears rather large," said the memo from Dr. Maurice R. Hilleman, an internationally renowned vaccinologist. "The key issue is whether thimerosal, in the amount given with the vaccine, does or does not constitute a safety hazard. ... However, perception of hazard may be equally important."

Schwarzenegger letter

Furthermore Dr. Wolfgang Maurer, an Austrian vaccinologist, wrote a letter to California Gov. Arnold Schwarzenegger when that state was considering thimerosal legislation. A copy of the letter, obtained by the Southeast Missourian, says that Mauer discussed the issue with regulators from the FDA and the World Health Organization in 1993. He said he made at least four vaccine manufacturers aware of his concerns in 1993.

Despite the ongoing science that supports the theory, the anti-thimerosal faction has not put forth enough evidence of harm to change the minds of the government health officials. And the government health organizations have not shown enough science to silence the theorists.

"Unfortunately, there seems to be a double standard with science when it concerns vaccines," said Sallie Bernard, executive director of SAFE MINDS, an acronym for Sensible Action for Ending Mercury-Induced Neurological Disorders. "We have higher hurdles. Even though we have a high number of studies that point in the direction that thimerosal and mercury in general has the ability to cause autism, they keep wanting more."

Bernard said that autism rates should start falling this year if the thimerosal theory is correct.

<A HREF = "mailto:bmiller@semissourian.com">bmiller@semissourian.com</A>

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