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Are flu shots safe for young children?

Despite public health recommendations that children ages 6 months to 23 months should be vaccinated against the flu, some parents are holding off because of concerns about the safety of the vaccine.
Boy cries as he gets flu vaccine shot at doctors office
Alexander Stapleton, 2, cries as a doctor gives him a flu shot at a medical center in Great Neck, N.Y., on Oct. 22.Shannon Stapleton / Reuters
/ Source: contributor

While other people may be concerned about the shortage of flu shots, parents of young children have a completely different issue to ponder: whether or not to even get their kids vaccinated.

The government recommends that children ages 6 months to 23 months and others in high-risk categories get vaccinated. But many parents are confused about the safety and long-term repercussions of the vaccine on their children. In particular, they are concerned about thimerosal, a form of mercury used in small amounts as a preservative in most flu vaccines.

Some researchers and patient advocacy groups have long charged there is a possible link between thimerosal and autistic spectrum disorder. Thimerosal is used as an antibacterial/antifungal agent in a variety of medications, such as throat and nose sprays, and even contact-lens solutions. And, since the 1930s, it's been used as a preservative in many vaccines, enabling manufacturers to offer the drugs in larger vials, which can be used to vaccinate several patients instead of just one.

Compound banned from childhood vaccines
In the late 1990s, the U.S. Public Health Service and the American Academy of Pediatrics agreed that as a precautionary measure, vaccines given to children should be thimerosal-free or contain only trace amounts of the preservative, explains Dr. Julia McMillan, professor of pediatrics at Johns Hopkins University and a member of the American Academy of Pediatrics committee on infectious diseases. By 2003, all early childhood vaccines in the United States were thimerosal-free. Except, that is, for the flu vaccine.

Of course, any parent would wonder why the flu shot with thimerosal is supposedly safe for kids when the other vaccines that contained the chemical were not considered safe. According to McMillan, it wasn’t that thimerosal was ever considered unsafe; it was removed solely because there was a lack of information about its safety.

“When we made the recommendation it was because we just didn’t have enough information about mercury. The FDA was reviewing it for use in dentistry, drugs and so forth. We decided since more children were getting more vaccines and being exposed to thimerosal at a rate we hadn’t considered before, it would be best to minimize the exposure as a precaution,” she says.

Ethyl mercury vs. methyl mercury
While we know that mercury exposure causes neurological disorders and that humans should limit their exposure, the real risk comes from a form of mercury called methyl mercury, says Dr. Robert Roberts, an immunologist and professor of pediatrics at the UCLA School of Medicine. Thimerosal contains ethyl mercury, a different form of the chemical. Ethyl mercury is metabolized differently than the toxic methyl form and excreted quickly.

“Chemically, the way the mercury (in the flu shot) is bound, it just can’t be utilized by the body like other forms of mercury,” says Roberts. “That’s why the flu shot is perfectly safe.” 

Roberts says, however, that it makes sense that parents of children with autism are looking everywhere — even to vaccinations — for potential answers.

Dr. Wilbert Mason, professor of clinical pediatrics at the University of Southern California School of Medicine and head of the division of infectious diseases at Children’s Hospital Los Angeles also says he understand why parents cringe at the thought of any sort of mercury — even a minute amount of the innocuous type — being injected into their children’s veins. But, he says, according to the latest science, the pain from the shot is the worst thing about it.

Teams of top researchers in the United States and elsewhere have failed to find any link between vaccinations with thimerosal and autism spectrum disorder, says Mason.

This year the Institute of Medicine released an exhaustive survey of published and unpublished studies looking for a possible link between thimerosal and autism. The report, called "Immunization and Safety Report: Vaccines and Autism," found no link. Studies published in the Sept. 2004 issue of the journal Pediatrics concurred with the findings. Interestingly, Mason notes that a well-regarded Danish study found not only no risk to children from thimerosal, but, ironically, a statistical benefit.

“In Denmark, thimerosal was removed from vaccines in the early to mid-‘90s,” explains Mason. “They have a very tight health-care system with a national database so there’s no question about the dose and the fact that the children received it. Analysis of their data showed no association between thimerosal and autism. In fact, they found a negative association. They actually found less autism in the children who were given the vaccines with thimerosal than without,” says Mason.

This finding probably doesn’t mean that thimerosal protects against autism; it more likely means that the number of children diagnosed with autism has risen in Denmark as it has here, adds Mason.

So what's a parent to do?
Fervent believers in the autism-thimerosal link remain, however. Dr. Stephanie Cave, a family physician in Baton Rouge, La., and author of "What Your Doctor May Not Tell You About Children’s Vaccinations," holds fast to the claim. She says the U.S. government wouldn’t have ordered the removal of thimerosal from other vaccines if it didn’t pose a potential problem.

Autism is mercury and aluminum toxicity,” says Cave, who adds that she successfully treats children with autism spectrum disorder in her practice by prescribing medicine to rid their bodies of these heavy metals. Yet, Cave concedes that a child must have a genetic predisposition to autism for thimerosal to pose a risk. She also isn’t categorically opposed to the flu shot.

“I don’t have a problem with the flu vaccination, but I do have a problem with thimerosal,” she says. Cave advises parents to get only thimerosal-free flu shots for their children. Some pediatricians offer them to patients, although given how difficult it is to find even a regular flu shot this season, they could be tough to locate. Local health departments may have information on where to find thimerosal-free vaccines.

In addition, Cave claims that the risk influenza poses to children has been overblown. “We’ve overplayed the risk. People think deaths (of children) due to flu are in the thousands and they’re not,” says Cave, who tells parents to keep children out of crowds and encourage frequent hand washing as an alternative deterrent during flu season.

But, according to Mason, when you consider not only the flu but also flu-related complications, such as secondary bacterial infections like ear infections, sinus infections and pneumonia, it's difficult to overplay the risk. Many of these complications are common and can come on fast and furious in young children. In fact, kids are just as likely as the elderly to be hospitalized due to the flu, Mason notes. He urges parents to vaccinate their children against the illness. Period.

“One hundred fifty children died last year of flu-related complications. That’s real,” says Mason. “The autism issue is at very best hypothetical. We should be much more concerned about real risks versus hypothetical or, in my opinion, nonexistent risks.”

Victoria Clayton is a freelance writer based in California and co-author of the new book "Fearless Pregnancy: Wisdom and Reassurance from a Doctor, a Midwife and a Mom," published by Fair Winds Press.