Aluminum in Vaccines Not Culprit in Kids’ Chronic Diseases, Study Shows

Cumulative aluminum exposure from vaccination during the first 2 years of life did not raise the risk of autism, asthma, or other chronic disorders, a 24-year study of over 1.2 million children in Denmark showed.

Adjusted hazard ratios (HRs) per 1-mg increase in aluminum exposure were 0.93 (95% CI 0.90-0.97) for any neurodevelopmental disorder, 0.98 (95% CI 0.94-1.02) for any autoimmune disorder, and 0.99 (95% CI 0.98-1.01) for any atopic or allergic disorder, reported Niklas Worm Andersson, MD, PhD, of the Statens Serum Institut in Copenhagen, and co-authors in Annals of Internal Medicine.

“Aluminum salts in the extremely small amounts present in some childhood vaccines are not associated with increased risk of 50 health conditions in early childhood,” stated co-author Anders Hviid, MSc, DrMedSci, also of Statens Serum Institut.

“Our results, based on 1.2 million Danish children and a study period covering 24 years, provide robust evidence supporting the safety of childhood vaccines,” Hviid told MedPage Today. “This is evidence that parents, clinicians, and public health officials need to make the best choices for the health of our children.”

The findings help close the evidence gap about aluminum-adsorbed vaccines and adverse events, especially neurologic disorders, the researchers said.

They also come as conversations about aluminum in vaccines rise to the forefront in the U.S. Last month, HHS Secretary Robert F. Kennedy Jr. considered asking a key government vaccine advisory panel to examine vaccines with aluminum ingredients, presumably due to questions about aluminum’s potential ties to chronic conditions.

Aluminum is the most abundant metal in the earth’s crust and is present in most foods and drinks. While infants receive about 4.4 mg of aluminum during their first 6 months from vaccines, they receive more from their diet: breast-fed infants ingest about 7 mg, formula-fed infants consume about 38 mg, and infants fed soy formula get almost 117 mg of aluminum in those first 6 months.

Aluminum salts have been added to vaccines since the 1930s.

“The adjuvant allows you to develop an immune response that is protective, which you wouldn’t otherwise have,” Paul Offit, MD, of Children’s Hospital of Philadelphia, said in an interview with MedPage Today. “It allows for lesser quantities of the actual vaccine, and it allows for fewer doses.”

The present Denmark study “answers a lot of questions,” said Offit, who wasn’t involved with the report. Its strength lies in the Danish national healthcare system, he pointed out. “The access to data is much easier in that system than it is here, where data are more fragmented,” he said.

In 2022, an analysis of Vaccine Safety Datalink (VSD) records led by Matthew Daley, MD, of Kaiser Permanente Colorado, found a possible association between aluminum exposure from vaccines and persistent asthma in a cohort of children. “While recognizing the small effect sizes identified and the potential for unmeasured confounding, additional investigation of this hypothesis appears warranted,” Daley and colleagues wrote at the time.

The CDC did not change vaccine recommendations based on the lone VSD study but said that “further investigation is needed into this potential safety signal.”

The VSD study left several questions unanswered: “They didn’t control for breastfeeding, which is protective against asthma,” Offit said. “They didn’t control for environmental pollution, which increases the risk of asthma. Most importantly, they didn’t control for family history.”

The Denmark study aimed to answer these questions, with preliminary results presented to the CDC’s Advisory Committee on Immunization Practices in 2023.

Study Details

Andersson and colleagues studied 1,224,176 children born in Denmark between 1997 and 2018, during which vaccines with varying aluminum content were introduced. Diphtheria-tetanus-pertussis, Haemophilus influenzae type B, pneumococcal conjugate vaccine, inactivated poliovirus, and hepatitis A and B vaccines were included.

The researchers used nationwide health registries to determine the cumulative aluminum exposure from childhood vaccines administered to each child before age 2 years, and to provide clinical data on the children through 2020 or until they reached age 5 years, died, or were lost to follow-up.

Study authors sought to investigate the incidence of 50 chronic diseases in particular, including 36 autoimmune, nine atopic or allergic, and five neurodevelopmental disorders. Among these 50 conditions were some very rare diseases and some more typically diagnosed after 5 years of age.

The researchers used regression models to estimate adjusted HRs when children received 1 additional mg of aluminum in vaccines by age 2 years compared with children who received 1 mg less.

For autism spectrum disorder, the HR per 1-mg increase in cumulative aluminum exposure from childhood vaccination was 0.93 (95% CI 0.89-0.97), and for attention-deficit/hyperactivity disorder, it was 0.90 (95% CI 0.84-0.96). For asthma, the HR was 0.96 (95% CI 0.94-0.98).

For most individual outcomes, findings were inconsistent with moderate-to-large relative risk increases, though small relative effects for some rare disorders could not be excluded. “Our findings do not suggest an association, but these are rarer conditions, so the statistical precision in our results is lower,” Hviid said.

The analysis had several limitations, the researchers acknowledged. Because the study relied on data from routine clinical practice, exposure was not random. The researchers adjusted findings for a wide range of covariates including socioeconomic status, but residual confounding still may have influenced results.

MedPage Today. She writes about brain aging, Alzheimeru2019s disease, dementia, MS, rare diseases, epilepsy, autism, headache, stroke, Parkinsonu2019s disease, ALS, concussion, CTE, sleep, pain, and more. Judy started her career with the Congressional watchdog agency GAO and has been a magazine reporter, academic text editor, and radio producer. She holds a BA in English from University of Detroit, MBA from Xavier University, and attended Columbia Radcliffe Publishing Course. Besides writing about neurology, sheu2019s reported on topics ranging from mental health to environmental contamination. Her work has been published in outlets as diverse as Business Week, Conde Nast’s Self, and AlterNet.”,”affiliation”:””,”credential”:””,”url_identifier”:”jg8109″,”avatar_url”:””,”avatar_alt_text”:”Judy George”,”twitter”:”https://twitter.com/MedPageNeuro”,”byline”:”Deputy Managing Editor, MedPage Today”,”full_name”:”Judy George”,”title”:”Deputy Managing Editor, MedPage Today, “,”url”:”https://www.medpagetoday.com/people/jg8109/judy-george”}]”>