BACKGROUND AND PURPOSE:

• Aluminum based adjuvants are common in childhood vaccines (e.g. Tdap), and are used to increase the immune response to the vaccine
  • Findings from animal studies have caused theoretical concern
  • There is no evidence from human studies
• Andersson et al. (Annals of Internal Medicine, 2025) assessed the association between cumulative aluminum exposure from early childhood vaccination and risk for autoimmune, atopic or allergic, and neurodevelopmental disorders

METHODS:

• Population-based cohort study
  • Danish national Medical Birth Registry
• Population
  • Children born between 1997 and 2017
• Exposures
  • Cumulative aluminum amount received (per 1-mg increase) through vaccination during the first 2 years of life
• Primary outcomes
  • Incident events of 50 chronic disorders, including
    • Autoimmune: Dermatologic | Endocrinologic | Hematologic | Gastrointestinal | Rheumatic
    • Atopic or allergic: Asthma | Atopic dermatitis | Rhinoconjunctivitis | Allergy
    • Neurodevelopmental: Autism spectrum disorder | Attention deficit–hyperactivity disorder

RESULTS:

• 1,224,176 children born in Denmark
• 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 any autoimmune disorder
    • Adjusted hazard ratio (aHR) per 1 mg increase in aluminum exposure 0.98 (95% CI, 0.94 to 1.02)
  • For any atopic or allergic disorder
    • aHR per 1 mg increase in aluminum exposure 0.99 (95% CI, 0.98 to 1.01)
  • For any neurodevelopmental disorder
    • aHR per 1 mg increase in aluminum exposure 0.93 (95% CI, 0.90 to 0.97)
• For most of the outcomes analyzed individually, the upper bounds of the 95% CIs precluded relative increases greater than 10% or 30%
  • None of the assessed outcomes had a 95% CI with a lower bound greater than 1.00

CONCLUSION:

• The results of this large population-based study of cumulative aluminum exposure due to early childhood vaccination are most compatible with no increase in risk with exposure
• However, the authors note that a small relative risk increase cannot be statistically excluded, especially for rarer outcomes
• The authors state

Our study, based on a nationwide cohort of about 1.2 million children with analyses across a 24-year period, offers a large-scale, population-based evaluation of the safety of aluminum-adsorbed vaccines in childhood vaccination programs

Learn More – Primary Sources:

Aluminum-Adsorbed Vaccines and Chronic Diseases in Childhood: A Nationwide Cohort Study