Study: Risk of Autism Not Increased by Number of Vaccines in Young Children
Nearly 1 in 10 parents delay or completely refuse vaccinations for their children because they believe there’s a risk in giving their children too many vaccines too soon. Approximately one-third of parents express concerns that vaccines cause autism, although scientific evidence suggests there is no causal effect. A new study scheduled for publication in The Journal of Pediatrics, concludes there is no association between receiving too many vaccines too soon and autism.
Researchers from the Centers for Disease Control and Prevention analyzed data from the study. The data was compiled from three managed care organizations that included 256 children with autism spectrum disorder and 752 children without ASD. Dr. Frank DeStefano and colleagues from the CDC and Abt Associates, Inc. reviewed each child’s cumulative exposure to antigens and the maximum number of antigens each child received in a single day of vaccination. Antigens are the substances in vaccines that cause the immune system to produce antibodies to fight off disease.
By adding the number of different antigens in all vaccines each child received in one day, as well as all vaccines each child received up to 2 years of age, the researchers determined the total antigen numbers. Their findings were that the total antigens from vaccines received by age 2, or the maximum number received on a single day, was the same between children with and without ASD. This data suggests, when comparing antigen numbers, that there is no relationship between vaccinations and subcategories of autistic disorder and ASD with regression.
Today, the maximum number of antigens a child could be exposed to by age 2 is 315. In the late 1990s, that number was several thousand. While the difference is great, there are actually more routine childhood vaccinations now than in the past in the CDC’s recommended vaccine schedule. Different vaccines contain varying amounts of antigens. Changes in vaccines over the years can account for a staggering variance in antigen production, so the researchers in this study acknowledged that merely counting the number of vaccines received doesn’t account for how different vaccines and combinations can stimulate the immune system.
“The possibility that immunological stimulation from vaccines during the first 1 or 2 years of life could be related to the development of ASD is not well-supported by what is known about the neurobiology of ASDs,” according to the study’s authors. A review published in 2004 by the Institute of Medicine concluded there is no causal relationship between certain vaccine types and autism. This study supports those findings.