The vaccine preservative thimerosal has jumped the safety hurdle. Again. So indicates a recent large epidemiological study in the New England Journal of Medicine. "Again" is the problem, though. One huge study after another has cleared thimersorosal as a cause of child developmental disorders, and specifically autism, but there is a powerful lobby that couldn't care less.
Thimerosal, used in vaccines since the 1930s but phased out in 2001 for everything but flu shots, comprises about 50 percent ethyl mercury. It neither contains nor degrades into the pollutant methyl mercury that pregnant mothers are warned about in fish. (Though that said, the Maternal Nutrition Group, a coalition of nutrition groups and experts including several federal agencies, recently released
a report calling on pregnant women to eat far more fish, citing in part a low risk from methyl mercury.)
In this latest study, Centers for Disease Control and Prevention researchers evaluated more than 1,000 children between the ages of seven and 10 who were exposed to various levels of thimerosal at different early stages in life. They made almost 400 different statistical comparisons.
They assessed "42 neuropsychological outcomes and found few significant associations with exposure to mercury from vaccines and immune globulins administered prenatally or during the first 7 months of life," adding that those associations were as likely to be positive as negative.
It was not a study of autism, the disease activists most prefer to link to thimerosal. But the brain damage theories of the autism alarmists make it incredible to think that the chemical could cause only one or even a few brain development disorders.
Further, a multitude of earlier studies have specifically looked for a thimerosal-autism link and found none, including a 2004 214-page Institute of Medicine
summary of them.
California has become a statistical battleground because the state's Department of Development Services, in its online
FactStats quarterly reports, tracks all the autistic children it serves. Anti-vaccinationists insist the data show a drop in autism since thimerosal was eliminated from childhood vaccines. In reality, the rate continues to climb at the same rate as before.
Further, California isn't our only test case. Published studies have also shown a continued increase in autism cases after thimerosal's removal from vaccines during the 1990s in Sweden, Denmark, and Canada. Medically, this is a slam dunk.
But "It doesn't seem to matter what the studies and the data show," Kristen Ehresmann, a Minnesota Department of Health official told The New York Times.
That's because parents are flooded with false information from three strange bedfellows.
First are the far-right anti-fluoridation types, most specifically the
Association of American Physicians and Surgeons, Inc. Second are environmentalist crusaders like
Bobby Kennedy Jr. and the
Environmental Working Group. They deliberately confuse the ethyl mercury in thimerosal with the methyl mercury in fish to encourage animosity towards coal-fired power plants,
the primary man-made source of mercury emissions.
Third are grass-roots conspiracy groups that usually oppose all vaccinations, but especially childhood ones. There are over 150 anti-vaccine web sites that feel science shouldn't impede their message to parents who often can't distinguish between scientific studies and mere anecdotes.
Thus we find former Playboy Playmate Jenny McCarthy treated as an expert when she claims on Oprah, and in the new book she's hawking, that her son got autism from a vaccine. What's a 214-page study against that massive 38 C IQ of hers?
Unfortunately all of this scares parents away from vaccination programs, which is bad for everyone. It destroys "herd immunity," which means immunization rates in the wider population are high enough to protect those not immunized. (It's 85 percent for diphtheria, for example.)
Diseases we used to refer to in past tense, like pertussis (whooping cough), have made comebacks in countries as diverse as Australia, Japan, and Sweden after anti-vaccinationist scares. Pertussis cases went from fewer than 8,000 in the U.S. in 2001 to over 25,000 in 2005.
Any vaccine will cause some side effects if given to tens of millions of people. But there's no evidence that any vaccine has ever caused a single case of autism.
Scaring the hell out of parents is utterly unconscionable. "Suffer the little children" should not become a working principle.
