The World Health Organization (WHO) has issued a definitive scientific statement reaffirming that vaccines do not cause autism spectrum disorders (ASD), countering longstanding misinformation and recent controversial claims from some health authorities. This comes after an extensive review of global research by the WHO’s Global Advisory Committee on Vaccine Safety (GACVS).
During its meeting on 27 November 2025, the expert committee analysed evidence from 31 high-quality studies published between January 2010 and August 2025, involving data from multiple countries. The review focused on both general childhood vaccines and vaccines containing preservatives such as thiomersal, as well as aluminium adjuvants, which have been the subject of past speculation.
The committee concluded that there is no causal link between any vaccines and the development of autism spectrum disorders, reaffirming WHO’s longstanding position on vaccine safety. It also validated that trace amounts of aluminium used safely in some vaccines do not contribute to ASD.
“Vaccines, including those with thiomersal and/or aluminium, do not cause autism,” the WHO statement said, echoing similar findings from previous reviews issued in 2002, 2004 and 2012. The body encouraged national health authorities to continue basing immunisation policies on the strongest available scientific evidence.
The reaffirmation is particularly timely amid a resurgence of public debate over vaccine safety in some countries. In recent months, the U.S. Centers for Disease Control and Prevention (CDC) revised its online guidance in a way that critics say undermined decades of scientific consensus by suggesting that an autism link had not been fully ruled out. WHO’s latest analysis directly counters this narrative, emphasising that robust evidence supports vaccine safety and that no credible research shows a vaccine-autism connection.
Autism is currently understood by experts to be a neurodevelopmental condition influenced by complex genetic and biological factors, not caused by vaccines—despite the persistence of myths dating back to a now-discredited study from 1998.
WHO also stressed the public health importance of immunisation. Childhood vaccines remain one of the most successful medical interventions in history, preventing serious diseases and saving millions of lives worldwide. Maintaining high vaccination coverage, the organisation said, is critical to protecting children, families and communities from preventable illnesses.
Public health officials and experts hope this clear scientific reaffirmation will help reduce vaccine hesitancy and strengthen trust in immunisation programmes globally.
