In this case-controlled study, 83 children with "autistic disorder" were compared to 80 control children for Tylenol/Acetaminophen use. When looking at children 5 years of age or less, those administered the drug following a measles-mumps-rubella vaccine were over 6 times more likely to develop autism. As described in the full-text, children who used acetaminophen at age 12 to 18 months vs. those who did not were eight times more likely to have autism spectrum disorder when all children were considered and nearly 21 times more likely to have ASD when limiting cases to children with regression in development. Ibuprofen use at age 12 to 18 months was not significantly associated with ASD for either of these groups.
The 6 scientists in the study concluded by stating - "This preliminary study found that acetaminophen use after measles-mumps-rubella vaccination was associated with autistic disorder."
ABSTRACTThe present study was performed to determine whether acetaminophen (paracetamol) use after the measles-mumps-rubella vaccination could be associated with autistic disorder. This case-control study used the results of an online parental survey conducted from 16 July 2005 to 30 January 2006, consisting of 83 children with autistic disorder and 80 control children. Acetaminophen use after measles-mumps-rubella vaccination was significantly associated with autistic disorder when considering children 5 years of age or less (OR 6.11, 95% CI 1.42-26.3), after limiting cases to children with regression in development (OR 3.97, 95% CI 1.11-14.3), and when considering only children who had post-vaccination sequelae (OR 8.23, 95% CI 1.56-43.3), adjusting for age, gender, mother's ethnicity, and the presence of illness concurrent with measles-mumps-rubella vaccination. Ibuprofen use after measles-mumps-rubella vaccination was not associated with autistic disorder. This preliminary study found that acetaminophen use after measles-mumps-rubella vaccination was associated with autistic disorder.