No Link Found Between Aluminum in Childhood Vaccines and Autoimmune Disorders

A recent study reported no evidence supporting the link between early childhood exposure to aluminum-absorbed vaccines and an increased risk for autoimmune, atopic, allergic, or neurodevelopmental disorders.¹

“The upper bounds of the 95% CIs for the combined outcome groups were incompatible with relative risk increases greater than 2% for autoimmune disorders, 1% for atopic or allergic disorders, and any increase for neurodevelopmental disorders, per 1-mg increase in aluminum exposure through early childhood vaccination,” wrote investigators, led by Niklas Worm Andersson, MD, PhD, from the department of epidemiology research at Statens Serum Institut, in Denmark.

Aluminum-based adjuvants are often used in inactivated vaccines to boost the immune response and assist the absorption of vaccine antigens. Vaccines for diphtheria, tetanus, pertussis, Haemophilus influenzae type b (Hib), hepatitis A, and hepatitis B use aluminum-based adjuvants.

Even though physicians have been administering aluminum-absorbed vaccines in children for decades, animal studies have raised concerns about potential neurotoxic effects.² Studies have shown that aluminum-absorbed vaccines may increase the risk for autoimmunity and atopic disorders.^3,4

Although animal studies have suggested a potential link, there is a lack of human-based studies that assess this association. The literature only includes preclinical, ecological, and smaller observational studies. In this cohort study, investigators sought to assess the link between cumulative aluminum exposure from early childhood vaccination and the risk for autoimmune, atopic, allergic, and neurodevelopmental disorders.¹

Andersson and colleagues linked nationwide Denmark data on childhood vaccinations, outcome diagnoses, and potential confounders. The sample included 1,224,176 children, 48.7% female, born in Denmark between 1997 and 2018, who lived in the country at 2 years old and received aluminum through vaccinations.

Each dose of vaccine had an aluminum content ranging from 0.125 to 1.00 mg. The total aluminum exposure at age 2 years was a median of 3 mg (IQR, 2.8 to 3.4).

Investigators collected data on incident events of 50 chronic disorders, including autoimmune (dermatologic, endocrinologic, hematologic, gastrointestinal, rheumatic), atopic or allergic (asthma, atopic dermatitis, rhinoconjunctivitis, allergy), and neurodevelopmental (autism spectrum disorder and ADHD).

The study found that cumulative aluminum exposure from vaccination during early childhood was not linked to increased rates of autoimmune, atopic, allergic, and neurodevelopmental disorders. The adjusted hazard ratios per 1-mg increase in aluminum exposure were 0.98 (95% confidence interval [CI], 0.94 to 1.02) for any autoimmune disorder, 0.99 (95% CI, 0.98 to 1.10) for any atopic or allergic disorder, and 0.93 (95% CI, 0.90 to 0.97) for any neurodevelopmental disorder.

Autoimmune disorders were relatively rare in the sample, with incidence rates ranging from 0.8 to 50.5 per 100,000 person-years. Only 16 autoimmune disorders were individually studied, including rheumatoid arthritis, Hashimoto thyroiditis, idiopathic thrombocytopenic purpura, hypothyroidism, vitiligo, Kawasaki disease, juvenile arthritis, type 1 diabetes, vasculitis unspecified, celiac disease, Crohn disease, psoriasis, henoach-schönlein purpura, myositis, ulcerative colitis, and erythema. The upper bounds of the CIs were 1.10 or lower for 8 outcomes, 1.30 or lower for 5 outcomes, and between 1.31 and 1.63 for the remaining 3 outcomes.

For atopic or allergic disorders, the most common were asthma, atopic dermatitis, and allergic rhinitis, with hazard ratios per 1-mg increase in cumulative aluminum exposure from childhood vaccination of 0.96, 1.02, and 0.99, respectively. The upper bounds of the CIs were 1.10 or lower for 8 of the individually analyzed outcomes and 1.78 for insect sting allergy.

As for neurodevelopmental disorders, the hazard ratios per 1-mg increase in the cumulative aluminum exposure from childhood vaccination were 0.93 (95% CI, 0.89 to 0.97) for autism spectrum disorder and 0.90 (95% CI, 0.84 to 0.96) for ADHD. Except for Asperger syndrome (HR, 1.13) and atypical autism (HR, 0.94), estimates for the individual outcomes were incompatible with any increased risk; the upper bounds of the CIs were below 1.00.

“In this nationwide cohort study of approximately 1.2 million children, estimates of the associations between cumulative aluminum exposure from early childhood vaccination and chronic autoimmune, atopic or allergic, and neurodevelopmental disorders were incompatible with moderate to large relative increases in risk and most consistent with no increased risk, but small relative increases in risk could not be statistically excluded, particularly for some rarer outcomes,” investigators concluded.

References

1. Andersson NW, Bech Svalgaard I, Hoffmann SS, Hviid A. Aluminum-Adsorbed Vaccines and Chronic Diseases in Childhood : A Nationwide Cohort Study. Ann Intern Med. Published online July 15, 2025. doi:10.7326/ANNALS-25-00997

2. Willhite CC, Karyakina NA, Yokel RA, et al. Systematic review of potential health risks posed by pharmaceutical, occupational and consumer exposures to metallic and nanoscale aluminum, aluminum oxides, aluminum hydroxide and its soluble salts. Crit Rev Toxicol. 2014;44 Suppl 4(Suppl 4):1-80. doi:10.3109/10408444.2014.934439

3. Willhite CC, Karyakina NA, Yokel RA, et al. Systematic review of potential health risks posed by pharmaceutical, occupational and consumer exposures to metallic and nanoscale aluminum, aluminum oxides, aluminum hydroxide and its soluble salts. Crit Rev Toxicol. 2014;44 Suppl 4(Suppl 4):1-80. doi:10.3109/10408444.2014.934439

4. Tomljenovic L, Shaw CA. Do aluminum vaccine adjuvants contribute to the rising prevalence of autism?. J Inorg Biochem. 2011;105(11):1489-1499. doi:10.1016/j.jinorgbio.2011.08.008