Autistic spectrum disorder: No causal relationship with vaccines.

Although immunization is known to provide effective life-saving benefits for children, it has sometimes been blamed for an array of diseases that have unknown causes (eg, autistic spectrum disorder [ASD], multiple sclerosis and sudden infant death syndrome). This is not surprising, given that immunizations are common and that humans are primed to attribute causality to events that precede an incident. We all use the ‘after it, because of it’ logic. This is how we learned not to touch a hot stove as young children. Unfortunately, this logic can be faulty. Causality assessment requires careful consideration of a wide range of factors. Beyond the temporal relationship, the consistency of the finding, the strength of the association, the specificity of the association and the biological plausibility, all need to be evaluated before attributing causality [1][2]. The present article reviews recent controversies surrounding immunizations and ASD, and concludes that there are no data to support any association between immunization and ASD. The current article replaces the 2001 statement entitled “Measles-mumps-rubella vaccine and autistic spectrum disorder: A hypothesis only” [3].