Has the U.S. government acknowledged a link between childhood vaccines and autism?
A Maryland-born girl who has a rare genetic mitochondrial disorder and features of autism was recently compensated in a landmark case filed under the National Childhood Vaccine Injury Act. The Centers for Disease Control and Prevention says the "government has made absolutely no statement indicating that vaccines are a cause of autism" - a position supported by decades of research that has found no link between vaccines and autism. Yet an autism advocacy group claims otherwise.
So what's happening? And how should millions of nervous parents react?
The former Ellicott City girl, the daughter of a neurologist, was well until she was 7 months old, when she suffered recurrent ear infections. She reportedly developed normally until 19 months, at which time she received five common childhood vaccinations. After this visit, her development deteriorated and she was eventually diagnosed with a rare disorder that affects the energy-generating parts of our cells, and features of autism.
The award to her family creates confusion among the families of the infants ready to receive vaccines. A few days ago, a mother of one of my patients, herself a doctor, asked me why the government had made the award if the vaccines were not the cause of autism. The answer lies in a misunderstanding of the mechanism under which the girl was compensated.
Autism is a developmental disorder that affects the ability to understand language and relate to others. We now refer to "autism spectrum disorders" and "pervasive developmental disorders" as categories of autism. The rate of children diagnosed with autism has increased steadily over the last 20 years, but it remains unclear whether we are seeing an increase in autism or merely reclassifying children who were classified as having other developmental-delay disorders in the past. The rate of children diagnosed with mental retardation has declined significantly over the last decade for similarly unclear reasons.
Dozens of large-scale studies from multiple countries have failed to prove the association of MMR (measles-mumps-rubella) vaccine and autism, or between thimerosal (the mercury preservative that used to be in vaccines) and autism, and national reports from organizations such as the prestigious Institute of Medicine reject any association between vaccines and autism. Nevertheless, a large and vocal group of anti-vaccine proponents persist in making the claim that there is a causative link.
