The truth about mercury & vaccines II

I posted about this topic earlier and it got a fair amount of attention, so here is an excerpt from a recent WSJ editorial on the subject. (Also read this more detailed piece and this piece as well, both from Tech Central Station on the subject.)

This is a story of politics and lawyers trumping science and medicine. It concerns thimerosal, a preservative that was used in vaccines for 60 years and has never been credibly linked to any health problems. Nonetheless, a small but vocal group of parents have taken to claiming that thimerosal causes autism, a brain disorder that impairs normal social interaction. The result has been an ugly legal and political spat that has spilled into Congress and is frightening some parents from vaccinating their children against such deadly diseases as tetanus and whooping cough.

Like night follows day, the dispute has also brought in the trial lawyers. Vaccine makers are supposed to be protected from lawsuits by 1986 legislation, but the lawyers are exploiting loopholes to file billion-dollar suits that threaten to punish the few companies that still make vaccines.

Congress tried to fix this by including a liability provision in homeland security legislation a year ago. But three Northeast Republican Senators -- Olympia Snowe, Susan Collins and Lincoln Chafee -- demanded it be taken out until Congress could have a full airing of the thimerosal-autism issue. The Senators haven't yet honored their side of that deal.

Perhaps that's because if they did their position would be exposed as scientifically untenable. The claim is that thimerosal, an organic mercury compound, can cause neurodevelopmental disorders. But study after study has shown that there is simply no such link.

A 2002 University of Rochester study compared the blood mercury levels of infants who'd received vaccines with and without thimerosal. All had levels well below the super-cautious EPA safety standard. This was followed last March by a study published in Pediatrics magazine, in which researchers compared the physical manifestations of autism and mercury poisoning. They found that the symptoms weren't the same, nor were the brain tissues similar.

Perhaps the best evidence comes from Denmark, one of those European nations that likes to monitor most everything about its citizens. Researchers recently examined the health records of all children born in Denmark from 1971 to 2000 for autism diagnoses. Though Denmark eliminated thimerosal from its vaccines in 1992, the researchers found that the incidence of autism continued to increase. A second research team reviewed the records of nearly 500,000 Danes vaccinated for pertussis. They also found that the risk of autism and related disorders didn't differ between those vaccinated with thimerosal and those without.

None of this is to deny that the incidence of autism may be rising, though there is a dispute about why. The definition of the disease has broadened in recent years, encompassing even mild learning disabilities, and doctors have become better at diagnosing it. Some statistics show that as autism diagnoses rise, those for mental retardation fall -- suggesting children were previously misdiagnosed. Parents are also more keen to have a proper diagnosis, because many schools now offer more extensive educational services for autism than they do for other disorders.