This study compares the rate of pervasive developmental disorders (including autism) in a group of 5,763 individuals in the UK against weather they had received the MMR vaccine or not. Of those with pervasive developmental disorders 78.1% had received the MMR vaccine, an of those without 82.1% had received the MMR vaccine. No association was found between MMR vaccine and pervasive developmental disorders, between MMR vaccine and autism, or between early MMR vaccination and pervasive developmental disorders.