The U.S. health agency is re-examining the safety of aluminum salts in childhood vaccines, a move that could reshape the nation’s vaccination schedule.
New Focus on Aluminum Salt Safety
Earlier this month, members of the Centers for Disease Control and Prevention’s vaccine advisory committee-selected by Health Secretary Robert F. Kennedy Jr. after he fired the previous group-suggested a deeper look into concerns about aluminum salts. Andrew Nixon, a spokesperson for the Department of Health and Human Services, told NBC News that the committee is “reviewing the body of science related to aluminum and other possible contaminants in childhood vaccine[s].”
A statement posted on the CDC website last month said HHS is investigating whether aluminum in vaccines could be linked to autism. The agency clarified that aluminum salts are not a contaminant but an adjuvant, added to boost the immune response and allow smaller vaccine doses. Nearly a century of evidence has found it safe for this purpose.
Expert Voices on Aluminum Adjuvants
Dr. Michelle Fiscus, chief medical officer at the Association of Immunization Managers, explained the role of aluminum: “This is not the thing that you wrap your food in at the barbecue. … The purpose of them is to just help the immune system respond a little more robustly to that vaccine.”
She added, “Aluminum adjuvants have made vaccines very, very effective and have helped us significantly reduce suffering and sickness and death.”
Political Rhetoric and Vaccine Schedule Debate
President Donald Trump, in a September news conference, said aluminum was being “taken out of the vaccines” while warning that Tylenol use in pregnancy may be linked to autism. He added, “Who the hell wants that pumped into a body?”
During the CDC’s vaccine advisory panel meeting, Dr. Tracy Beth Høeg, acting director of the FDA’s Center for Drug Evaluation and Research, argued for adopting Denmark’s sparser vaccine schedule, noting that it would reduce aluminum exposure. “I do not feel like we have the data to show that there is an established safe amount [of aluminum] that children can receive before the age of 2, before the age of 18,” Høeg said.
Several outlets reported that the Trump administration was considering decreasing the number of recommended childhood vaccines to align more closely with Denmark’s, citing an unnamed source familiar with the plans.
Changes to the U.S. Vaccine Recommendations
The CDC’s vaccine advisory committee already voted to stop recommending the hepatitis B vaccine for all newborns. As a result, the CDC now advises women who test negative for the virus to decide about the shot with their medical providers.
Changing vaccine recommendations based on concerns about aluminum salts would be a flimsy justification, several public health experts said. Even in Denmark, many recommended vaccines contain aluminum salts, including those for human papillomavirus (HPV), pneumococcal disease, tetanus and whooping cough.
Of the pediatric vaccines on the CDC’s schedule that are missing from Denmark’s universal recommendations, just three-hepatitis A, hepatitis B and meningococcal vaccines-contain aluminum salts. The others-respiratory syncytial virus (RSV), rotavirus, flu and chickenpox-do not.
The measles, mumps and rubella (MMR) vaccine, often cited by anti-vaccine activists as linked to autism, also does not contain aluminum salts.
Scientific Evidence on Aluminum and Autism
A study of more than 1.2 million children in Denmark, published in July in the journal Annals of Internal Medicine, found no link between aluminum salts from vaccines and neurodevelopmental disorders, including autism.
Kennedy demanded the paper be retracted. “A closer look reveals a study so deeply flawed it functions not as science but as a deceitful propaganda stunt by the pharmaceutical industry,” he wrote in an editorial on the website TrialSite News.
Kennedy argued that the paper excluded some children who may have been at risk and did not include a control group. However, Annals of Internal Medicine stood by the study and said there was no reason to retract it.
Historical Context and Legal Background
Kennedy, a longtime critic of vaccines, had been involved in lawsuits against the pharmaceutical company Merck over allegations related to its HPV vaccine, which contains aluminum salts. Since taking office, he has said any fees earned would go to one of his sons.
His focus on aluminum dates back to his time as chairman and chief litigation counsel at the anti-vaccine group Children’s Health Defense. The group has claimed for years that thimerosal-a mercury-based preservative-was linked to autism, and Kennedy said in a 2020 podcast that aluminum had replaced thimerosal in some vaccines, causing them to remain toxic.
In reality, thimerosal was largely phased out of childhood vaccines in 2001. Under Kennedy’s leadership, HHS in July pulled the ingredient from the roughly 5% of flu vaccines that still had it.
A recent analysis from the World Health Organization found no link between autism and vaccines containing thimerosal or aluminum.
Allergies and Other Health Concerns
In 2021, Kennedy told food blogger Mikhaila Peterson that all aluminum-containing vaccines had “negative risk profiles” and that the brains of children with autism were “loaded with aluminum.” He suggested that kids develop food allergies because “we’ve been inducing allergies by pumping them full of aluminum.”
A large German study in 2011 did not find an increased risk of allergies in vaccinated children and even identified a decrease in hay fever among the group. In 2023, a study found a positive association between vaccine-related aluminum exposure and persistent asthma, but the results couldn’t be replicated and scientists said the research didn’t properly control for confounding variables.
Reanalysis of Existing Data
In response to mounting hesitancy about aluminum salts in vaccines, Dr. Seth Ari Sim-Son Hoffman, a physician-scientist at Stanford Medicine, reanalyzed existing data with colleagues. The team’s findings, published this month in the journal Pediatrics, found no major safety concerns with aluminum-containing vaccines. Side effects were mostly limited to redness and swelling at the injection site.
“When you see the same ‘no’ finding or ‘no’ association across multiple countries, multiple study designs and over a million children, that’s really, really clear and reassuring,” Hoffman said.
He added, “The current childhood vaccine schedule in the U.S., he added, ‘is backed by powerful evidence in terms of safety and effectiveness.'”
Key Takeaways
- The CDC’s vaccine advisory committee is re-examining aluminum salts in childhood vaccines under new leadership.
- Scientific studies, including a large Danish cohort and a recent U.S. reanalysis, find no link between aluminum in vaccines and autism or other neurodevelopmental disorders.
- Political and public-health debates continue over potential changes to the U.S. vaccine schedule, with some officials advocating for a sparser schedule similar to Denmark’s.
The ongoing scrutiny of aluminum salts underscores the complex interplay between scientific evidence, public perception, and policy decisions in shaping the U.S. childhood vaccine landscape.
