Today, the Journal of Pediatrics published the first major study to look specifically at a possible link between autism and increasing exposure to the immune-stimulating compounds in early childhood vaccines.
The researchers analyzed the vaccination and medical records of more than a thousand children in three managed care organizations. They totaled each child’s exposure to the immune-stimulating compounds, or antigens, in vaccines up to age 2. (Vaccines vary in the amount of antigens they contain.) The researchers also totaled the maximum exposure to vaccine antigens that each child received in any single day. They then tracked the children’s development through at least age 6.
They found no link between increased risk of autism spectrum disorder (ASD) and higher exposures to vaccine antigens in the first two years of life or on any one day. More specifically, they looked for associations with regressive autism. This subtype of autism involves the development and later loss of early language skills. Here, too, they found no association with increased early exposure to the immune-stimulating compounds in vaccines.
“This study adds to the existing epidemiological studies showing no link between vaccines and autism,” noted Chief Science Officer Geri Dawson, PhD. “This research is very important for addressing the concerns of families. However, we still don’t fully understand the causes of autism. It is crucial that we increase research funding on both the causes and more effective treatments for autism.”
The case-control study was led by epidemiologists in the Immunization Safety Office of the Centers for Disease Control and Prevention (CDC). It included 256 children with diagnosed ASD and 752 normally developing children matched by birth year and gender. Among those with autism, 49 had experienced regression. All the children were enrolled in one of three managed healthcare programs. All those diagnosed with autism underwent in-person assessments. Born between 1994 and 1999, the children received their vaccinations between 1994 and 2002.
The researchers note that the immunization schedule in effect during those years included vaccines that were cruder, or more antigenic, than current vaccines. As such, they were more likely to cause side effects. “Even though the routine childhood schedule in 2012 contains several more vaccines than the schedule in the late 1990s,” they write, “the maximum number of antigens to which a child could be exposed by age 2 years was 315 in 2012, compared with several thousand in the late 1990s.”
Read the full study report here.