WHO Reaffirms No Link Between Vaccines and Autism, Defies US Review
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A comprehensive review by the World Health Organization (WHO) has once again confirmed that there is no evidence to support a link between childhood vaccines and autism, a finding that stands in contrast to a recent push for renewed investigation by US health officials.
The WHO’s findings, published Thursday, are based on an examination of over 25 years of research, including a review of 31 new studies conducted over the past 15 years. The Global Advisory Committee on Vaccine Safety (GAVS) found no causal link between vaccines and autism spectrum disorder (ASD), nor did it find any connection between vaccines containing preservatives like thimerosal or aluminum and the development of ASD.
The renewed WHO assessment comes amid growing concern over statements made by US Health and Human Services Secretary Robert F. Kennedy Jr., who has recently revived long-discredited theories about a potential link between vaccines and autism. In March, Kennedy directed the US Centers for Disease Control and Prevention (CDC) to conduct a new review of the topic, a process that remains incomplete. He also ordered the CDC to alter language on its website, moving away from a definitive statement that “studies have shown there is no link between receiving vaccines and developing autism spectrum disorder.”
Following these directives, the CDC website was updated to state that the claim “vaccines do not cause autism” is “not an evidence-based claim,” a change that sparked widespread criticism from vaccine experts. Further text on the site suggests that “scientific studies have not ruled out the possibility that infant vaccines contribute to the development of autism.” However, a separate CDC page dedicated to thimerosal and vaccine safety maintains that “research does not show any link between thimerosal in vaccines and autism, a neurodevelopmental disorder,” and correctly notes that the mercury-based preservative has been removed from nearly all childhood vaccines for decades, with some flu vaccines being the exception.
The WHO committee also specifically addressed concerns surrounding aluminum salts, commonly used as adjuvants in vaccines for diseases like hepatitis A, hepatitis B, diphtheria, tetanus, pertussis (DTaP), and Human Papillomavirus (HPV). Their review found no evidence linking the use of these adjuvants to an increased risk of autism.
Vaccines: A Cornerstone of Global Health
The WHO Director-General, Dr. Tedros Adhanom Ghebreyesus, underscored the critical role of vaccines in improving global health outcomes. “Over the past 25 years, under-five mortality has dropped by more than half, from 11 million deaths a year to 4.8 million, and vaccines are the major reason for that,” he stated during a press briefing. He further emphasized that vaccines are “among the most powerful, transformative inventions in the history of humankind,” capable of saving lives from approximately 30 different diseases, including measles, cervical cancer, and malaria.
While acknowledging that, like all medical products, vaccines can cause side effects, Dr. Tedros firmly affirmed, “autism is not a side effect of vaccines.”
This latest review represents the fourth such assessment by the WHO, following similar investigations in 2002, 2004, and 2012. Each review has consistently reached the same conclusion: vaccines do not cause autism. The current study encompassed evidence gathered over a 25-year period.
US Stance Creates International Friction
Kennedy’s actions have not only sparked domestic controversy but have also created tension with international health organizations. He has also reportedly reduced US support for global polio vaccine efforts and criticized Gavi, the Vaccine Alliance, regarding its DPT vaccination strategies. Recently, a CDC vaccine advisory committee, reportedly comprised of vaccine skeptics, recommended against routine hepatitis B vaccination for newborns, a decision widely condemned by experts.
Katherine O’Brien, WHO head of Vaccines and Biologicals, emphasized the global consensus on vaccine safety. “Not only has the WHO undertaken evidence reviews, but numerous advisory bodies around the world have consistently come to the same conclusions about the lack of risk of thimerosal or aluminum related to the autism questions,” she said. The WHO develops its recommendations through independent committees of experts drawn from around the globe to ensure an unbiased review of the evidence.
When questioned about potential pressure from the US to reconsider its position, Dr. Tedros stated unequivocally, “We disagree. We disagree respectfully, and we say no, because this is a science-based organization, and science has to be respected.” He acknowledged the US decision to withdraw from the WHO in January 2026 but noted that pressures from member states are not uncommon. “I can give you many examples from the US, China, Russia and others,” he added.
