New WHO Analysis Reaffirms Vaccine Safety
Geneva: The World Health Organization (WHO) today reaffirmed that vaccines do not cause autism spectrum disorders (ASD), following a comprehensive review by its Global Advisory Committee on Vaccine Safety (GACVS). The analysis, which examined evidence from 31 studies conducted across multiple countries over the past 15 years, found no causal link between vaccines—including those containing thiomersal, a mercury-based preservative, or aluminium adjuvants, compounds used to enhance immune response—and ASD.
“This new analysis confirms what the scientific community has consistently shown,” WHO Director-General Dr Tedros Adhanom Ghebreyesus said in remarks at a media briefing organised by the African, Caribbean, and North American Union (ACANU). “Based on available evidence, there is no causal link between vaccines and autism. The committee concluded that the evidence shows no link between vaccines and autism, including vaccines containing aluminium or thiomersal.”
The committee first examined the relationship between thiomersal-containing vaccines and ASD, before expanding its assessment to vaccines in general. It also reviewed a range of studies on vaccines with aluminium adjuvants, including a large Danish cohort study covering children born between 1997 and 2018. The findings strongly support the safety of vaccines used during childhood and pregnancy and confirm the absence of any causal link with autism.
“This is the fourth such review of the evidence, following similar reviews in 2002, 2004 and 2012. All reached the same conclusion: vaccines do not cause autism,” Dr Tedros said. He recalled the 1998 study published in The Lancet that falsely suggested a link between vaccines and autism, describing it as “fraudulent” and noting that the study was later retracted. “But the damage had been done, and the idea has never gone away,” he added.
Vaccines, Dr Tedros emphasised, remain among the most powerful and transformative inventions in human history, saving lives from about 30 diseases, including measles, cervical cancer, and malaria. “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 said. While all medical products can cause side effects, autism is not one of them. Vaccines are also critical for adults, protecting against diseases such as COVID-19 and seasonal influenza.
The briefing highlighted current health risks, including the northern hemisphere’s flu season and the circulation of the so-called K subclade of H3N2 influenza viruses, which WHO has observed increasing since August. Although disease severity has not risen, Dr Tedros stressed that vaccines remain essential for high-risk populations and their caregivers. On COVID-19, he noted that the virus continues to evolve, with the recent designation of variant BA.3.2 under monitoring. Approximately 6% of people infected experience post-COVID-19 conditions, or “long COVID,” underscoring the continued importance of vaccination.
WHO also reaffirmed the critical role of vaccines in broader global health initiatives. The organisation has worked to expand Universal Health Coverage (UHC), ensuring that immunisation is part of essential health services for all. The latest UHC Global Monitoring Report, launched with the World Bank, shows progress since 2000, but highlights that 4.6 billion people still lack access to essential health services and 2.1 billion face financial hardship due to health costs.
Dr Tedros placed the vaccine findings within the context of WHO’s achievements and challenges in 2025. Landmark accomplishments include the adoption of the WHO Pandemic Agreement, the negotiation of the Pathogen Access and Benefit Sharing (PABS) system, and the entry into force of amendments to the International Health Regulations, strengthening global health security. WHO has also supported disease elimination efforts, including the Maldives’ “triple elimination” of mother-to-child transmission of HIV, syphilis, and hepatitis B, the elimination of trachoma, sleeping sickness, river blindness, and malaria in multiple countries, and certification of Georgia, Suriname, and Timor-Leste as malaria-free. Seven new countries introduced WHO-approved malaria vaccines, bringing the total to 24. On HIV, the WHO prequalified injectable lenacapavir and issued guidelines to accelerate rollout.
Emergency responses were also highlighted. In 2025, the WHO responded to 48 emergencies in 79 countries, providing essential health services to more than 30 million people. The organisation shipped 56 million doses of cholera vaccine to 14 countries, supported over 10,600 medical evacuations in Gaza, delivered nearly 3,000 metric tons of medical supplies to Sudan, and conducted 18,500 health consultations in Ukraine. Dr Tedros warned of the rising number of attacks on health care—1,272 verified attacks this year alone, causing nearly 2,000 deaths and over 1,100 injuries—and called on all combatants to respect international law.
The briefing also addressed WHO’s financial and operational challenges. Funding cuts, including the announced U.S. withdrawal, left the WHO facing a projected $500 million salary gap. The organisation has tightened its budget, reduced its workforce, and launched a plan to increase assessed contributions to 50% of the base budget by 2031, strengthening long-term sustainability and independence.
Despite these challenges, Dr Tedros affirmed WHO’s enduring mission: “The world continues to need WHO, and we remain committed to the vision the nations of the world had when they founded this organisation in 1948: the highest attainable standard of health – not as a luxury for some, but a right for all.”
– global bihari bureau
