This evidence brief examines childhood autism, including claims around paracetamol and vaccination. It addresses misinformation and explains the science that demonstrates that there is no evidence for a causal link between autism and paracetamol, or autism and vaccines. It outlines the causes of autism, autism trends in Australia and factors linked to the rising prevalence of autism.

Autism Spectrum Disorder (often referred to as autism or ASD) is the collective diagnostic term for multiple congenital neurodevelopmental conditions characterised by persistent social interaction and communication difficulties and restricted behavioural patterns. There is no single cause of autism, it comes from a complex interplay between genes and environmental factors that can influence development, usually in utero. 

Key insights

• Family history is one of the strongest predictors of autism and hundreds of genetic variants have been identified.
• On paracetamol, the brief highlights while some studies have reported weak associations with autism, large-scale sibling and cohort studies demonstrate no causal link.
• Regulatory bodies in Australia and internationally continue to recommend paracetamol in pregnancy when used as directed, noting that untreated fever itself poses significant risks.
• On vaccination, decades of high-quality research including systematic reviews, meta-analyses, and national registry studies involving millions of children worldwide have found no link between vaccination and autism.
• The brief also notes that vaccination remains one of the most effective public health measures, preventing 3.5–5 million deaths globally each year.