New Study Challenges Concerns About Aluminum in Vaccines
Anti-vaccine activists often raise alarms about the safety of childhood vaccinations, frequently highlighting aluminum salts, which are added to many vaccines to enhance their effectiveness.
A recent large-scale study from Denmark disputes these claims. Researchers examined the vaccination and medical records of over 1.2 million children over a 24-year span and found no significant evidence that exposure to aluminum in vaccines correlates with a higher risk of various health issues commonly diagnosed in children, including asthma and autism.
Out of 50 evaluated conditions—spanning autoimmune diseases, allergies, and neurodevelopmental disorders—none showed elevated rates that would suggest any substantial risk associated with aluminum exposure. Senior researcher Anders Hviid noted this finding was “quite striking.”
“We can exclude meaningful increases with a large degree of certainty for many of these outcomes,” Hviid, who leads the epidemiology research department at Statens Serum Institut, Denmark’s public health agency, shared in an interview.
“We shouldn’t be worried about aluminum as an adjuvant in childhood vaccinations. That’s the main takeaway.”
Hviid and his team clarified that while they didn’t observe a significant rise in any studied conditions, it’s tough to completely dismiss the possibility of a minor risk related to extremely rare conditions. “This suggests there isn’t an epidemic of chronic diseases in childhood linked to aluminum in vaccines,” he explained.
This study was published on Monday in the journal Annals of Internal Medicine.
Experts in the field echoed Hviid’s conclusions regarding these findings. Anna Durbin, the director of the Center for Immunization Research at Johns Hopkins Bloomberg School of Public Health, expressed optimism, especially regarding asthma, as it has been a concern among vaccine-hesitant groups.
Matthew Daley and Jason Glanz, authors of a previous U.S. study that hinted at a potential connection between aluminum in vaccines and increased asthma risk in young children, welcomed this new research. Both researchers, affiliated with Kaiser Permanente Colorado’s Institute for Health Research, regarded the Danish study as thorough.
Particularly addressing asthma concerns, Daley remarked that this new evidence should reassure parents that adhering to vaccination schedules won’t heighten their children’s asthma risk.
“As a pediatrician, this finding is reassuring, and I believe my patients and fellow clinicians should feel the same way,” said Daley, noting that he had continued to advocate for vaccinations despite his earlier concerns about aluminum.
Aluminum salts serve to improve immune responses in certain childhood vaccines and are used in inactivated vaccines along with protein-based ones. Notably, vaccines using live attenuated viruses, such as the measles, mumps, and rubella vaccine, do not contain aluminum, nor do many mRNA vaccines, such as those for COVID-19.
These aluminum salts have been part of vaccinations for over seven decades, backed by extensive research supporting their safety. However, they have attracted scrutiny from vaccine critics who worry they might overstimulate the immune system. Importantly, the amount of aluminum children receive through vaccines remains well below safety thresholds.
The study by Daley and his co-authors was motivated by a 2013 report from the Institute of Medicine—now called the National Academy of Medicine—that recommended further research into the relationship between aluminum exposure and asthma development. Following their results in the journal Academic Pediatrics, Hviid and his team were inspired to reassess the topic.
“I’m grateful that they conducted this study,” Daley mentioned.
Researching the safety of aluminum in vaccines is complex, largely because aluminum is everywhere—it’s the third-most prevalent element on Earth, as Glanz pointed out. Daily exposure comes from various sources, including food and even breast milk.
Hviid’s team utilized Denmark’s national health care registries to create a cohort of 1.2 million children born between 1997 and 2018, tracking diagnoses of 50 conditions as they grew. They analyzed children’s health records up to the age of five.
Since the number of vaccines administered in early childhood evolved over the 24-year period, the researchers assessed whether the rates of any conditions shifted as aluminum exposure through vaccinations increased with the introduction of new vaccines.
Daley emphasized the robustness of the study’s design, noting that a lack of differences among children receiving higher numbers of early vaccinations is a positive indication. If there were a biological effect, it would likely intensify with increased exposure—this concept is known as dose response.
“They did not observe any dose response at all. Their study was structured to identify one if it existed,” he stated.
While acknowledging some limitations, Daley noted slight differences between the vaccination schedules in Denmark and the U.S. “In Denmark, they immunize at 3 months, 5 months, and 12 months. Here, it’s at 2 months, 4 months, 6 months, and 12 months. I doubt that such a small variation would make a sizeable difference, but it’s worth acknowledging,” he added.
Additionally, this isn’t a randomized controlled trial, as they did not compare children receiving aluminum-containing vaccines with those who didn’t, an unethical scenario that would risk exposing children to serious diseases.
Even so, Hviid emphasized that the large scale and clarity of the study reinforce the safety of these crucial vaccines.
“These aluminum-adjuvanted vaccines are essential for our immunization programs—not just in Denmark, but worldwide. Alternatives with different adjuvants aren’t available. Removing these vaccines would endanger children’s lives,” he concluded.
