This week’s New Scientist drew my attention to a report published recently by the US Centers for Disease Control and Prevention about the prevalence of ASD in the USA. The report shows that the prevalence of autism in 14 areas of the USA has risen by 78% between 2002 and 2008. Interestingly, in these same areas and across the USA, Thiomersal, the mercury-based vaccine preservative that has been blamed by some researchers for the rising prevalence of ASD, was phased out of paediatric vaccines from the year 2000 onwards. As the children in this latest study have not been exposed to Thiomersal, the obvious conclusion is that it does not play a role in the increasing rates of diagnosis of ASD. This replicates findings from other large-scale studies carried out worldwide which have also concluded that there is no link between vaccinations and ASD.