Effects of childhood immunizations on the onset of autism spectrum disorders and risk factors that predict current levels of autistic symptomology and adaptive functioning

Abstract

Scope and Method of Study: Autism spectrum disorders (autism, Asperger's, PDD) are devastating neurological disorders characterized by varying degrees of impairment in communication skills, social interactions, and restricted, repetitive and stereotyped patterns of behavior. This study investigated the use of multi-valent and thimerosal-containing childhood vaccinations (particularly MMR) as well as the child's state of health at the time of immunization and their possible link to the onset of ASD. It was also investigated whether the presence of one or more parent and child risk characteristics predict current level of autistic symptomology and adaptive functioning. Parents of 114 participants diagnosed with an autism spectrum disorder completed a detailed developmental history form along with the Scales of Independent Behavior: Short Form and an Autism rating scale (Gilliam Autism Rating Scale or Asperger's Syndrome Diagnostic Scale). The developmental history form inquired about demographics, pregnancy, birth, developmental milestones, immunizations, diagnosis and other pertinent medical information.

Findings and Contributions: The results of this study confirmed no association between neither childhood immunizations nor the participant's state of health at the time of vaccination and the onset of an autism spectrum disorder. A statistically significant correlation was noted among the dependent variable, current level of autism symptomology and all independent variables (parent risk characteristics; family history noted to include psychological and/or learning disorders and length of gestation and child risk characteristics: the presence of the following to a marked degree during the first five years of life, physical sensitivity, impaired social interaction, developmental regression, and stereotypical/unusual behaviors). A statistically significant correlation was also noted among the dependent variable, current level of adaptive functioning and child risk characteristics as well as for the model including both parent risk characteristics and child risk characteristics.