For more than two decades, debates have swirled over the safety of childhood vaccines—a topic that refuses to fade despite stacks of scientific evidence. Now, on November 27, 2025, the World Health Organization’s (WHO) Global Advisory Committee on Vaccine Safety (GACVS) has delivered another clear verdict: there is still no evidence linking vaccines to autism spectrum disorders (ASD).
Major Global Review Covers 31 Studies
The committee, comprised of international vaccine safety experts, pored over 31 major studies published between 2010 and August 2025. Their review spanned data from multiple countries and took a close look at vaccines both in general and those containing specific ingredients like thiomersal—a preservative—and aluminum, long cited by some as causes for concern.
Their conclusion? “There is no association between the trace amounts of aluminium used in some vaccines and ASD,” the committee reported. Vaccines, including those with thiomersal and/or aluminum, simply do not cause autism. This aligns perfectly with GACVS’s previous statements from 2002, 2004, and 2012. The new review “strongly supports the positive safety profile of vaccines used during childhood and pregnancy,” according to WHO’s summary.
No Scientific Basis for Autism-Vaccine Claims
The WHO’s update comes against the backdrop of renewed political debate in the United States and global concern over the persistence of vaccine hesitancy. In September, WHO explicitly warned against reviving unfounded claims linking vaccines and autism, citing the damage such misinformation can do to public trust. Health officials underline that “decades of research” back up the safety and efficacy of vaccines—some of our most reliable tools for preventing disease.
The idea of a vaccine-autism link has been debunked repeatedly, yet it has lingered as a source of confusion and anxiety for parents. Notably, autism rates have continued to rise even in countries that phased out thiomersal in vaccines years ago, further highlighting that vaccines are not the cause. The current understanding of autism points to genetic factors and, possibly, other prenatal components—not ingredients in vaccines.
The WHO says it will continue to assess new research as it becomes available and will keep providing guidance based strictly on robust scientific evidence. For now, the message is unchanged and clearer than ever: vaccines, including those with thiomersal or aluminum, do not cause autism.
