WHO confirms no link between vaccines and autism after reviewing 31 major studies

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World Health Organisation (WHO) has said that there is no causal link between childhood vaccines and autism spectrum disorders (ASD). This conclusion is based on a new analysis by the WHO's Global Advisory Committee on Vaccine Safety (GACVS), which reviewed 31 major research studies published between January 2010 and August 2025.

ASD is a neurological and developmental disorder that affects a person's social interactions, communication, learning, and behaviour. People with autism frequently have co-occurring conditions such as epilepsy, depression, anxiety, and attention deficit hyperactivity disorder.

The recent analysis, discussed on November 27, focused first on the relationship between thiomersal-containing vaccines and ASD, as well as the association between vaccines in general and ASD.

Established in 1999, the GACVS also carried out an assessment of potential health concerns associated with vaccines containing aluminium adjuvants, focusing on studies conducted between 1999 and March 2023.

It additionally considered findings from a major cohort study based on nationwide registry data covering all children born in Denmark from 1997 to 2018.

The high-quality evidence reveals no link between trace amounts of aluminium used in some vaccines and ASD, hence supporting the continued use of vaccines containing aluminium adjuvants.

Following its study, the Committee reaffirms its prior results from 2002, 2004, and 2012: vaccines, particularly those containing thiomersal and/or aluminium, do not cause autism.

“WHO advises all national authorities to rely on the latest science and ensure vaccine policies are grounded in the strongest available evidence,” the report read.

The evidence strongly supports the positive safety profile of vaccines used during childhood and pregnancy and confirms that there is no association between vaccines, including those containing thiomersal and/or aluminium, and ASD.

Importance of Vaccination

Global childhood immunisation efforts have saved at least 154 million lives over the past 50 years, making it one of the greatest achievements in improving lives, livelihoods, and prosperity.