WHO Experts Reaffirm Vaccines Do Not Cause Autism After Global Safety Review

During its latest meeting on 27 November 2025, GACVS conducted a comprehensive review of the available scientific evidence on vaccines and ASD.

A new scientific review by a World Health Organization (WHO) global expert committee has reaffirmed that there is no causal link between vaccines and autism spectrum disorders (ASD), reinforcing WHO’s long-standing position on vaccine safety.

The findings come from the Global Advisory Committee on Vaccine Safety (GACVS), an independent body established by WHO in 1999 to provide authoritative scientific advice on vaccine safety issues of global importance. The Committee brings together leading international experts in epidemiology, immunology, toxicology and public health to assess emerging evidence and address public concerns.

During its latest meeting on 27 November 2025, GACVS conducted a comprehensive review of the available scientific evidence on vaccines and ASD. The analysis focused on two key areas: the potential association between thiomersal-containing vaccines and autism, and the relationship between childhood vaccines in general and ASD.

The Committee examined evidence from 31 high-quality primary research studies published between January 2010 and August 2025. These studies, conducted across multiple countries and populations, included large cohort studies, case-control analyses and systematic reviews. Collectively, the findings strongly support the safety of vaccines used during childhood and pregnancy and confirm the absence of any causal link with autism spectrum disorders.

In addition, GACVS reviewed evidence on the safety of aluminum adjuvants, which are used in some vaccines to enhance immune response. The Committee assessed studies conducted between 1999 and March 2023, as well as a recent large-scale cohort study based on nationwide registry data of children born in Denmark between 1997 and 2018. The analysis found no association between exposure to the trace amounts of aluminum used in vaccines and the development of ASD.

Based on this extensive review, the Committee reaffirmed its earlier conclusions issued in 2002, 2004 and 2012: vaccines, including those containing thiomersal and/or aluminum adjuvants, do not cause autism.

WHO emphasized that national health authorities should continue to rely on the strongest and most up-to-date scientific evidence when shaping vaccine policies and communicating with the public. The organization also highlighted the importance of addressing misinformation, which can undermine confidence in immunization and put public health at risk.

Global childhood immunization programmes remain one of the most effective public health interventions in history. Over the past 50 years, vaccines have saved an estimated 154 million lives worldwide, significantly reducing illness, disability and death from preventable diseases, while contributing to healthier societies and stronger economies.

WHO reiterated that maintaining high vaccination coverage is essential to protect individuals, families and communities, and to ensure continued progress in global health.