The government has decided not to warn parents a mercury-laced preservative virtually eliminated from other vaccines because of health concerns will be included in flu shots given to hundreds of thousands of infants and toddlers this fall.

The decision by the U.S. Centers for Disease Control and Prevention to recommend the shots with the preservative thimerosal – despite the pleas of parent activist groups – apparently conflicts with recent federal heath warnings about exposure to mercury, the Los Angeles Times reported.

Thimerosal is about 50 percent ethyl Mercury, a potent neurotoxin that has been removed from other childhood vaccines.

The CDC has added flu shots to its list of recommended vaccines for all young children.

Mercury-free flu vaccines will be available, for about $4 more per shot, but if the CDC were to warn parents, it might create a shortage resulting in some children not being immunized, the Times said.

The agency asserts, “The available scientific evidence has not shown thimerosal-containing vaccines to be harmful.”

Nevertheless, the CDC has ordered up to 2 million doses of thimerosal-free vaccine to make sure it meets the demand by health departments.

CDC senior scientist Roger Bernier explained, though, that stating a preference for thimerosal-free vaccines “would drive the demand even more aggressively.”

That isn’t necessary, he said, because there is no proof of harm – an assessment backed by the American Academy of Pediatrics.

But parent advocates are fuming, according to the L.A. paper.

Barbara Loe Fisher, co-founder of the National Vaccine Information Center, charges that by not advising parents, the government is “violating the precautionary principle which reminds doctors that, when in doubt, take an action which minimizes the risk of harm.”

Rep. David Weldon, R-Fla., said the CDC’s actions constitute “medical malpractice.”

The congressman, a physician, plans to introduce a bill to ban thimerosal in childhood vaccines.

Weldon said he would not allow his son to have the shot with mercury, the Times said, which is used to prevent the growth of bacteria and fungi in vaccines.

Thimerosal was the preservative of choice until 1999, when the U.S. Public Health Service and the academy of pediatrics called on drug firms to voluntarily remove it as a precaution.

Some parent groups and researchers believe thimerosal has contributed to a sharp increase in reported rates of autism and other neurological disorders in children.

Many scientists and vaccine makers insist, however, exposures are too low to have an effect and ethyl mercury can be more easily eliminated from the body than methyl mercury, which is produced by industrial emissions.

But Boyd E. Haley, chairman of the department of chemistry at the University of Kentucky, believes it is “preposterous and ridiculous” for the government to warn about methyl mercury in fish but sanction injecting ethyl mercury into children.

The CDC decision, which will be officially published later this month, is “unconscionable,” Haley said, according to the Times. “If it were my grandson or my granddaughter, there’s no way in hell you’d give them a vaccine containing thimerosal.”

Dr. Neal Halsey, director of the Institute for Vaccine Safety at Johns Hopkins Bloomberg School of Public Health, told the Times “it would make life much easier for everybody if there wasn’t the thimerosal in the vaccines.”

But he added: “I personally am not concerned.”

Halsey, who sounded the alarm about thimerosal in 1999, contends the situation now is different. The 1999 appeal referred to immunizations of infants, up to 6 months old, while flu shots with thimerosal would deliver only a 25-microgram dose to children 6 months and older.

So the exposure would be lower “in terms of the amount that’s given and the size of the child,” he told the Times.

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