Findings from a recent study found no link between aluminum in vaccines and autism, asthma, or 47 other health issues
The research tracked over 1.2 million Danish kids born between 1997–2018 using national health records.
The cumulative aluminum exposure showed no increased risk of any of the 50 adolescent childhood conditions measured—and even hints of slight protection for some conditions.
A recent nationwide Danish study, the biggest of its kind, has delivered clear, reassuring results for parents and health care providers alike.
Tracking more than 1.2 million children born in Denmark between 1997 and 2018, researchers looked at childhood vaccines containing a small amount of aluminum (used as an adjuvant to boost immunity).
They investigated whether these vaccines were associated with any long‑term health problems, such as allergies, autoimmune disorders, or neurodevelopmental issues like autism. The study found no evidence that vaccine‑related aluminum exposure was tied to increased health risks.
“Our results are reassuring,” researcher Anders Hviid said in a news release. “By analyzing data from more than one million Danish children, we found absolutely no indication that the very small amount of aluminum used in the childhood vaccination program increases the risk of 50 different health outcomes during childhood.
The study
Researchers from the Statens Serum Institut in Copenhagen linked Denmark’s health records—including birth, vaccination, and diagnosis data—to form a massive childhood cohort.
They estimated how much aluminum each child received from vaccines before they turned 2. Then they used statistical models to see whether an extra milligram of aluminum by age two affected the risk of developing any of 50 childhood disorders later on.
Children were followed from age 2 until age 5, the end of 2020, if they left the country, or died.
What the Results Mean
Overall, there was no increased risk of autism detected. The hazard ratios for all three condition groups hovered around 1 or even below—meaning no increase in risk, and in some cases a potential slight decrease.
For autism, the hazard ratio was 0.93 (CI 0.89–0.97); for ADHD it was 0.90 (CI 0.84–0.96). These are not clinically worrying and show no sign of harm from the aluminum component of vaccines.
The study didn’t look at rare outcomes or illnesses that appear only later in childhood. Also, it didn’t involve reviewing individual medical charts—but in Denmark, registry data is generally accurate.
“In an era marked by widespread misinformation about vaccines, it is crucial to rely on solid scientific evidence,” Hviid said in the news release.
“Large, population-based register studies like this one – tracking more than a million children over many years – is a bulwark against the politicization of health science which undermines public trust in vaccines. It is absolutely essential to distinguish real science from politically motivated campaigns – otherwise, it is the children who will end up paying the price.
Bottom Line for Parents
If you're a parent worried about aluminum in vaccines, this study is a major confidence booster. Large-scale and thorough, it confirms that the tiny aluminum amounts used in vaccines are not linked to autism, allergies, asthma, autoimmune conditions, ADHD—or any of the other 50 conditions studied.
“This is the first study of this scale and with such comprehensive analyses, and it confirms the strong safety profile of the vaccines we’ve used for decades in Denmark,” Hviid said.