Daijiworld Media Network - New Delhi
New Delhi, Dec 14: A fresh analysis by a World Health Organisation (WHO) global expert committee has found no evidence of any causal link between vaccines and autism spectrum disorders (ASD), reaffirming the UN health body’s long-standing position that childhood vaccines do not cause autism.
The findings were released on Friday following a review by the Global Advisory Committee on Vaccine Safety (GACVS), an independent panel of international experts set up in 1999 to advise WHO on vaccine safety-related issues.
WHO said autism spectrum disorders are a group of conditions marked by challenges in social interaction and communication, along with restricted or repetitive patterns of behaviour. While signs may appear in early childhood, diagnosis often happens later. Many individuals with autism also experience conditions such as epilepsy, anxiety, depression and attention deficit hyperactivity disorder, with intellectual abilities ranging from profound impairment to above-average levels.
The committee’s latest review, discussed on November 27, examined evidence on thiomersal-containing vaccines and vaccines in general in relation to ASD. Thiomersal, a mercury-based compound, has been used since the 1930s as a preservative in some vaccines and medicines to prevent microbial contamination.
According to WHO, the analysis assessed 31 primary research studies published between January 2010 and August 2025, drawing data from multiple countries. “The evidence strongly supports the safety of vaccines used during childhood and pregnancy and confirms the absence of a causal link with autism spectrum disorders,” the organisation said.
The panel also reviewed studies on vaccines containing aluminium adjuvants, analysing research conducted between 1999 and March 2023, including a large nationwide cohort study of children born in Denmark between 1997 and 2018. WHO said the available high-quality evidence shows no association between the trace amounts of aluminium used in some vaccines and ASD, supporting their continued use.
“Following its review, GACVS reaffirms its previous conclusions from 2002, 2004 and 2012 that vaccines, including those with thiomersal and/or aluminium, do not cause autism,” the WHO stated.
The organisation urged national authorities to base vaccine policies on the strongest available scientific evidence. It highlighted that global childhood immunisation is among the most successful public health interventions, with essential vaccines saving at least 154 million lives over the past 50 years and contributing to a 40 per cent reduction in infant mortality.
WHO clarified that an Adverse Event Following Immunization (AEFI) refers to any medical event occurring after vaccination and does not necessarily imply that the vaccine caused it. Only in extremely rare cases is a vaccine found to be the cause of such events.