Fears of Autism Not Affecting Immunization Rates
Despite Concerns About Thimerosal, Parents Still Vaccinating
By Adam Schoof
9/3/2008
Although the alleged link between childhood autism and the vaccine preservative thimerosal still sparks occasional controversy, the good news is that by and large, parents don't seem to be buying into the hype. According to the latest reports available from the CDC, overall childhood immunization rates in the United States continue to steadily increase.
Specifically, an Aug. 31, 2007, article in Morbidity and Mortality Weekly Report, or MMWR, included cumulative 2006 statistics for children ages 19-35 months that demonstrated "increases in national coverage with pneumococcal conjugate vaccine (PCV) and varicella vaccine (VAR) and a stable coverage level for the 4:3:1:3:3:1 vaccine series."
But that's not to say that FPs can relax their efforts to assuage parents' concerns about having their children vaccinated: The same MMWR article noted that national immunization coverage estimates remain below the target levels set by HHS' Healthy People 2010 initiative.
"Parents often want to confirm that the vaccines don't contain thimerosal," said family physician Sumi Sexton, M.D., of Arlington, Va. "Most have questions about vaccines, but still agree to vaccinate with the typical schedule."
FP Sanford Kimmel, M.D., of Toledo, Ohio, agreed.
"A recent audit conducted in our office of children ages 19-35 months found better than 95 percent immunization rates, except for hepatitis A vaccine, which has only recently been recommended," he said.
But that's not to say that FPs can relax their efforts to assuage parents' concerns about having their children vaccinated: The same MMWR article noted that national immunization coverage estimates remain below the target levels set by HHS' Healthy People 2010 initiative.
"Parents often want to confirm that the vaccines don't contain thimerosal," said family physician Sumi Sexton, M.D., of Arlington, Va. "Most have questions about vaccines, but still agree to vaccinate with the typical schedule."
FP Sanford Kimmel, M.D., of Toledo, Ohio, agreed.
"A recent audit conducted in our office of children ages 19-35 months found better than 95 percent immunization rates, except for hepatitis A vaccine, which has only recently been recommended," he said.
Thimerosal Removal Has Not Helped Autism Rates
According to the FDA, only two types of vaccinations recommended for children under age 6 years still contain thimerosal. Some formulations of the diphtheria, tetanus and acellular pertussis, or DTaP, vaccine and certain seasonal influenza vaccine products use minute or trace amounts of the preservative.
"Thimerosal was removed from vaccines because of concerns that some infants might be exposed to cumulative levels of mercury during the first 6 months of life that exceeded the maximum amount of mercury allowed by the EPA (Environmental Protection Agency)," Kimmel said. "The EPA guidelines, however, have as much as a 10-fold safety factor," he noted.
As previously reported in AAFP News Now, despite the widespread removal of thimerosal from U.S. vaccines within the past decade, rates of autism have remained constant.
"Since thimerosal has been virtually taken out of vaccines, the rates of autism have stayed the same. (If thimerosal was a cause of autism), we should be seeing a marked decrease in autism, but we're simply not," said family physician Doug Campos-Outcalt, M.D., M.P.A., of Phoenix, who serves as an AAFP liaison to the CDC's Advisory Committee on Immunization Practices.
Furthermore, he added, raising unfounded concerns about thimerosal in vaccines diverts attention from finding the actual causes of autism.
"Thimerosal was removed from vaccines because of concerns that some infants might be exposed to cumulative levels of mercury during the first 6 months of life that exceeded the maximum amount of mercury allowed by the EPA (Environmental Protection Agency)," Kimmel said. "The EPA guidelines, however, have as much as a 10-fold safety factor," he noted.
As previously reported in AAFP News Now, despite the widespread removal of thimerosal from U.S. vaccines within the past decade, rates of autism have remained constant.
"Since thimerosal has been virtually taken out of vaccines, the rates of autism have stayed the same. (If thimerosal was a cause of autism), we should be seeing a marked decrease in autism, but we're simply not," said family physician Doug Campos-Outcalt, M.D., M.P.A., of Phoenix, who serves as an AAFP liaison to the CDC's Advisory Committee on Immunization Practices.
Furthermore, he added, raising unfounded concerns about thimerosal in vaccines diverts attention from finding the actual causes of autism.
Delaying Immunization Yields Infection Risks
Some patients may seek an alternative vaccination schedule in which immunizations are delayed, Campos-Outcalt said. That's because parents often are concerned with the number of shots their children receive at one time.
But they're doing their kids no favors by taking that route, Kimmel warned.
"There is no evidence that delaying immunizations has any effect on lowering the risk of autism. In the interim, it increases the child's risk of acquiring a vaccine-preventable disease," he said.
Health care professionals can use various methods of conveying the importance of vaccines to patients. Sexton said she counsels concerned parents using consumer magazines such as Time and Parents, both of which recently featured articles about the purported vaccination-autism link.
But whichever method they use, Kimmel said, "It is important that family physicians be knowledgeable enough and take the time to address (a family's) concerns."
But they're doing their kids no favors by taking that route, Kimmel warned.
"There is no evidence that delaying immunizations has any effect on lowering the risk of autism. In the interim, it increases the child's risk of acquiring a vaccine-preventable disease," he said.
Health care professionals can use various methods of conveying the importance of vaccines to patients. Sexton said she counsels concerned parents using consumer magazines such as Time and Parents, both of which recently featured articles about the purported vaccination-autism link.
But whichever method they use, Kimmel said, "It is important that family physicians be knowledgeable enough and take the time to address (a family's) concerns."
