There is no causal link between MMR vaccine and autism

EDITOR—Nichol et al considerably understate their case when they write “chance alone dictates that some cases [of autism] will appear shortly after vaccination.”1 Such a temporal association is unremarkable, given the epidemiology of autism and MMR vaccine.

Over the time described by Wakefield et al2 MMR vaccine was given to around 600 000 children each year in Britain3 and the prevalence of autistic spectrum disorders was 91/100 000.4

Assuming that the diagnosis of autism is evenly distributed over the second and third years of life and that the incidence over this period approximates to the current prevalence,5 over the eight years that the reported cases represent autism would have been diagnosed in around 364 cases in the two months after MMR vaccination (the time that the authors regard as noteworthy (((91/100 000) ×600 000)×8)×(2/24)=364). …