Researchers have found in a new study involving over 1.2 million Danish children that there was no association between aluminum-adjuvanted childhood vaccines and the development of autoimmune, atopic, allergic, or neurodevelopmental conditions, including autism, reinforcing the safety of such vaccines. The study was published inAnnals of Internal Medicineby Niklas Worm and colleagues. This cohort study was performed in Denmark based on national registry data between 1997 and 2020. There were 1,224,176 children born between 1997 and 2018, who were alive and living in the country at two years of age. The analysis addressed the cumulative dose of aluminum from repeated childhood vaccination within the first two years of life. The study took advantage of natural variations in aluminum content between various vaccine formulations and time frames to evaluate associations with health endpoints. The incidence of 50 chronic diseases, categorized into three broad categories, was examined in the study: Autoimmune diseases: dermatologic, endocrinologic, hematologic, gastrointestinal, and rheumatic diseases. Atopic or allergic diseases: asthma, atopic dermatitis, rhinoconjunctivitis, and overall allergy. Neurodevelopmental diseases: autism spectrum disorder and attention deficit–hyperactivity disorder (ADHD). Researchers employed Cox proportional hazards regression models to model the risk per 1-mg increase in cumulative exposure to aluminum, controlling for covariates such as age, sex, race, comorbidities, and complications at birth. Key Findings No statistically significant elevation in the risk of any of the disorders evaluated with respect to aluminum exposure from vaccines was reported. Some findings included: Any autoimmune disorder: Adjusted hazard ratio (aHR) = 0.98 (95% Confidence Interval [CI]: 0.94 to 1.02)} Any allergic or atopic disorder: aHR = 0.99 (CI: 0.98 to 1.01) Any neurodevelopmental disorder: aHR = 0.93 (CI: 0.90 to 0.97) This large-scale national study found no support for an increased risk of autoimmune, allergic, or neurodevelopmental disease after early-life exposure to aluminum-adjuvanted vaccines. These findings are consistent with current guidelines for routine childhood immunization and serve to dispel myths regarding vaccine safety, and specifically those related to the use of aluminum adjuvants. Andersson, N. W., Bech Svalgaard, I., Hoffmann, S. S., & Hviid, A. (2025). Aluminum-adsorbed vaccines and chronic diseases in childhood: A nationwide cohort study. Annals of Internal Medicine, ANNALS-25-00997.https://doi.org/10.7326/annals-25-00997