No Link Found Between Aluminum in Vaccines and Chronic Disorders

The doctor is injecting a vaccination into the arm of a little girl.

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Aluminum is widely used as an adjuvant in nonlive vaccines administered during early childhood, enhancing immune response. Despite decades of use, concerns have persisted about possible links between aluminum-containing vaccines and the development of chronic conditions such as autoimmune diseases, allergic disorders, or neurodevelopmental issues. However, large-scale human safety data have been limited.

To address this gap, researchers conducted a comprehensive nationwide cohort study in Denmark, analyzing data from over 1.2 million children born between 1997 and 2018. The study, “Aluminum-Adsorbed Vaccines and Chronic Diseases in Childhood,” published today in Annals of Internal Medicineleveraged natural variations in aluminum content across different vaccines over time to evaluate whether cumulative aluminum exposure from vaccines given in the first 2 years of life was associated with later health outcomes.

Investigators examined the incidence of 50 chronic disorders, including a wide range of autoimmune conditions (dermatologic, endocrinologic, gastrointestinal, hematologic, and rheumatic), atopic or allergic conditions (such as asthma, eczema, and rhinitis), and neurodevelopmental disorders (specifically autism spectrum disorder and ADHD).

Their findings showed no increased risk of these disorders tied to higher cumulative aluminum exposure. Adjusted hazard ratios per 1-mg increase in aluminum were 0.98 for autoimmune diseases, 0.99 for atopic or allergic conditions, and notably 0.93 for neurodevelopmental disorders. These results suggest no association and even trends toward lower risk. For most outcomes, the data were inconsistent with even moderate increases in risk, though very small effects could not be ruled out for some rarer conditions.

Overall, this robust study provides important reassurance that early childhood exposure to aluminum-adsorbed vaccines does not appear linked to elevated risks for autoimmune, allergic, or neurodevelopmental disorders.

To learn more details of the study, Infection Control Today^®(ICT^®) spoke with professor of pharmacoepidemiology and the head of department, Department of Epidemiology Research at Statens Serum Institut (SSI), Anders Hviid, PhD, MSc, senior author on the paper.

ICT: What was the inspiration for this study?
Anders Hviid, PhD, MSc: There has long been public concern about the safety of vaccine ingredients, including aluminum-based adjuvants. While aluminum salts have been safely used in vaccines for decades, claims linking them to conditions such as autism, asthma and autoimmune diseases continue to circulate. We wanted to conduct a comprehensive study that could either confirm or refute these concerns. Using Denmark’s unique national health registers, we saw an opportunity to evaluate these associations in an unprecedentedly large and robust cohort of more than 1 million children.

ICT: What are the key takeaways?
AH: Our study found no association between exposure to aluminum-containing vaccines in childhood and the risk of developing any of the 50 different health conditions we examined, including autism, asthma, allergies, and autoimmune disorders. These results strongly support the safety of childhood immunization programs. Importantly, this is the largest study of its kind to date, and the comprehensiveness of our analyses allows us to say with confidence that aluminum in vaccines is highly unlikely to increase health risks during childhood.

ICT: With misinformation about vaccine ingredients still widespread, what do you see as the most important message from your research for policymakers, health care providers, and worried parents?
AH: The most important message is that science must lead the conversation. Our study offers robust, population-level evidence that can help counter fear-based narratives. Vaccine hesitancy often stems from uncertainty and distrust. By transparently publishing large-scale, methodologically sound studies like ours, we can strengthen public confidence in vaccines. Policymakers and health care professionals play a vital role in conveying these findings, and we hope this research gives them a powerful tool to reassure parents: The vaccines we give our children are not only effective, but also safe.