Ann Intern Med. 2025 Jul 15. doi: 10.7326/ANNALS-25-00997. Online ahead of print.
ABSTRACT
BACKGROUND: Aluminum is used as an adjuvant in nonlive vaccines administered in early childhood. Concerns persist about potential associations between vaccination with aluminum-adsorbed vaccines and increased risk for chronic autoimmunity, atopy or allergy, and neurodevelopmental disorders. Large-scale safety data remain limited.
OBJECTIVE: To assess the association between cumulative aluminum exposure from early childhood vaccination and risk for autoimmune, atopic or allergic, and neurodevelopmental disorders.
DESIGN: A cohort study linking nationwide registry data on childhood vaccinations, outcome diagnoses, and potential confounders, leveraging the variations in the aluminum content of childhood vaccines over time.
SETTING: Denmark, 1997 to 2020.
PARTICIPANTS: 1 224 176 children born in Denmark between 1997 and 2018 who were alive and residing in the country at age 2 years.
INTERVENTION: Cumulative aluminum amount received (per 1-mg increase) through vaccination during the first 2 years of life.
MEASUREMENTS: Incident events of 50 chronic disorders, including autoimmune (dermatologic, endocrinologic, hematologic, gastrointestinal, and rheumatic), atopic or allergic (asthma, atopic dermatitis, rhinoconjunctivitis, and allergy), and neurodevelopmental (autism spectrum disorder and attention deficit-hyperactivity disorder).
RESULTS: Cumulative aluminum exposure from vaccination during the first 2 years of life was not associated with increased rates of any of the 50 disorders assessed. For groups of combined outcomes, adjusted hazard ratios per 1-mg increase in aluminum exposure were 0.98 (95% CI, 0.94 to 1.02) for any autoimmune disorder, 0.99 (CI, 0.98 to 1.01) for any atopic or allergic disorder, and 0.93 (CI, 0.90 to 0.97) for any neurodevelopmental disorder. For most individually analyzed outcomes, the upper bounds of the 95% CIs were incompatible with relative increases greater than 10% or 30%.
LIMITATION: Individual medical records were not reviewed.
CONCLUSION: This nationwide cohort study did not find evidence supporting an increased risk for autoimmune, atopic or allergic, or neurodevelopmental disorders associated with early childhood exposure to aluminum-adsorbed vaccines. For most outcomes, the findings were inconsistent with moderate to large relative increases in risk, although small relative effects, particularly for some rarer disorders, could not be statistically excluded.
PRIMARY FUNDING SOURCE: None.
PMID:40658954 | DOI:10.7326/ANNALS-25-00997
