According to a 2002 review of antivaccination websites published in the Archives of Disease in Childhood, many sites used emotional appeals and cited seemingly convincing evidence that came from self-published studies (which don't undergo the peer review process required by medical journals). The researchers also found that it wasn't uncommon for the sites to publish statistics that came from questionable sources, including letters to newspaper editors and television interviews, rather than scientific research. Also, the review found, many of these sites promoted the idea of vaccinations as a "hoax" intended to generate profits for doctors and pharmaceutical companies.
"Despite all of the very hard work of epidemiologists to exonerate vaccines as a cause or to be implicated in autism, the lay public still seems to have rampant suspicion about what vaccines are used for and why we use them," says Dr. Joseph Domachowske, a fellow of the American Academy of Pediatrics and professor of pediatrics, microbiology and immunology at the State University of New York Upstate Medical University. "Until we can give people an answer as to what causes autism, there will still be some suspicion about vaccines." And the suspicion is causing concerned parents to lose sight of the bigger picture.
"People have forgotten about the infections that vaccines can prevent," he says. "And there's a misconception that vaccines are riskier than developing a vaccine-preventable infection." Those infections are on the rise in many parts of the world. Measles, one of the deadliest childhood illnesses, was all but eliminated in the U.S. before 2000 but last year saw the largest outbreak since then. And just this week, officials in Europe announced that cases of the mumps have doubled so far this year, compared with the same period last year.
Despite the scientific evidence, many parents still distrust childhood immunizations' safety. But why?
Trust experts, not celebrities or blogs
In general, says Dr. Domachowske, a majority of parents do vaccinate their children, but "they seem to want to know a whole lot more than in the past before they agree to it," he adds. If you need more information to put your mind at ease, though, rely on doctors and epidemiologists rather than emotional blogs that don't often rely on experts, he says. Nowadays, talk show hosts and magazines often treat celebrities as experts on the topic, and they often relay personal experiences, rather than science, in their interviews.
Ask for thimerosal-free vaccines
Even though most childhood vaccines no longer contain mercury-based preservatives, you can ask for thimerosal-free flu vaccines (the flu shot is the only one administered to children under 7 that still contains thimerosal). Dr. Domachowske notes that trace amounts of thimerosal left over from manufacturing expose children to very tiny amounts mercury, 1 microgram (mcg) or less per dose, according to the FDA. In comparison, exclusively breastfed infants will ingest 400 mcg of mercury by the time they're 6 months of age, just from normal environmental exposures to the mother (mercury in air and water) that pass into her breast milk. In the years while children are getting vaccinated, you can limit their exposure to other environmental sources of mercury: Buy a water filter to remove it from your water, and allow kids to eat canned tuna only once a month.
Know the schedule
According to a recent survey, only 9 percent of toddlers are up-to-date on their immunizations, but falling behind could make the vaccines less effective. A common concern expressed on antivaccine websites is that the one-size-fits-all vaccination schedule, which is set by the CDC, the American Academy of Pediatrics, and the American Academy of Family Physicians, doesn't take into account children's differing health needs. But be wary of "alternative" vaccine schedules not based on scientific evidence that are published in books and magazines. Talk to your doctor about your child's medical history if you're concerned that a vaccine may interact with an existing allergy or a past infection. And visit www.cdc.org/vaccines for an interactive tool that will help get your child back on track if you've fallen behind.
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