Last December, the U.S. Centers for Disease Control and Prevention increased its estimate of the number of U.S. children with autism spectrum disorder to 1 in 110 children aged 8. (The researchers used data for 8-year-olds because by age 8 most children have been identified as having this disorder for services.) This is an average increase of about 57 percent over the CDC’s previous study, held in 2002. These estimates also indicate that 1 in 70 boys and 1 in 315 girls have an autism spectrum disorder, which means its prevalence is four to five times higher for boys than for girls.
The perceived increase in the prevalence of autism in recent years has made it a highly contentious topic with a multitude of exceptionally vocal groups weighing in on the subject. Some argue that there are more diagnosed cases of autism because physicians and the general public have become more attentive to its symptoms. Others are certain that environmental pollutants play a significant role. Many more believe childhood vaccines, particularly the MMR vaccine, are to blame. Some in this group believe that thimerosal, a preservative in the MMR vaccine that contains mercury, had a role in causing autism, even though the Institute of Medicine (part of the National Academy of Sciences) concluded that there is no link between autism and vaccines made with thimerosal. (But because of continued public concern, thimerosal-free vaccines have been licensed since 1999, and today, the MMR vaccine no longer contains thimerosal as a preservative.)
Although these theories may be interesting in the press and help generate awareness about autism, studies have been inconclusive.
As a doctor, I base my medical decisions on sound, reliable science. While more scientific research needs to be done, we have no other significant large-scale studies to associate the MMR vaccine with autism. There are simply too many questions. But we do know for a fact that measles, mumps, and rubella are all very serious illnesses that can lead to severe long-term disabilities and even death. Until we have consistent research showing a connection between the MMR vaccine and autism spectrum disorder, I believe the potential benefits from receiving the vaccine far outweigh the risks. If I had young children today, I would have them vaccinated.
Regardless of your position on this controversial subject, I strongly encourage all parents to have a frank, honest discussion with their children’s doctor prior to making any medical decisions, including immunizations. Parents of young children also should watch for any signs of developmental issues with their children and talk to their doctors about any concerns.