Robert F. Kennedy Jr. He has trained his critique of vaccines on the basis of common ingredients. It's aluminum, which he suggests is the cause of a number of childhood illnesses, including food allergies, autism, and depression.
“You wonder why a whole generation of kids have allergies,” Kennedy said in a 2021 interview. “That's because we're triggering allergies and flooding them with aluminum.”
Aluminum is an odd target for many vaccine scientists. This is one of the most studied ingredients in vaccines, and perhaps modern medicine.
“There's a tremendous amount of information being collected,” says Dr. Andrew Racine, a pediatrician and chief medical officer at Montefiore Health System. “If something popped out about a lack of safety, we likely saw it somewhere, but it doesn't show up.”
Aluminum salts, a more soluble form of the metal, are added to vaccines such as the Tdap shot to strengthen the body's immune response. This ingredient has been repeatedly evaluated as part of vaccines in clinical trials, with billions of doses administered over decades.
Still, as Mr. Kennedy prepares for his confirmation hearing as Secretary of Health and Human Services, many experts say the standby vaccines will come under new scrutiny, and some, such as the hepatitis B shot, will We are concerned that this could be used to justify restricting children's access to vaccines. and pneumococcal disease.
Aaron Siri, a lawyer and close ally of Mr. Kennedy, told federal regulators on behalf of his clients that he is blocking the distribution of more than a dozen vaccines until manufacturers provide detailed information about the amount of aluminum in their formulations. I requested a temporary suspension.
Mr. Kennedy and Mr. Siri did not respond to requests for comment.
The origins of aluminum added to vaccines can be traced back nearly a century. A young veterinarian made a strange discovery in a stable on the outskirts of Paris. Mixing tapioca with equine diphtheria vaccine increases the vaccine's effectiveness.
Physician Gaston Ramon noticed that horses that developed a mild infection at the injection site had a much stronger immunity to diphtheria. He theorized that adding something to the shot that causes inflammation, an ingredient he later named an adjuvant from the Latin root for “to help,” helps trigger a stronger immune response.
After testing several candidates, including breadcrumbs, Vaseline, and rubber latex, he found success with an injection mixed with tapioca, which produced slight swelling and much more antibodies.
Tapioca never caught on as an adjuvant. However, in 1932, a few years after Dr. Ramon's research was published, the United States began including aluminum salts in diphtheria vaccinations. This is because aluminum salts were found to cause a similar, but more reliable effect.
Aluminum adjuvants are currently included in 27 routine vaccines, nearly half of which are recommended for children under 5 years of age.
This additional boost of immunity is not necessary with all types of vaccines. Vaccines containing attenuated viruses, such as the measles-mumps and rubella vaccines, or vaccines created using mRNA technology, such as the COVID-19 vaccines from Pfizer and Moderna, are capable of generating a strong enough immune response on their own. will generate.
But vaccines that contain only small fragments of the pathogen attract little attention from the immune system, so adjuvants can help stimulate a stronger response., Vaccines can be given in smaller doses.
Scientists believe that aluminum salts work in two ways. First, the aluminum binds to the vaccine's core component, allowing it to diffuse more slowly into the bloodstream, giving immune cells more time to mount a response.
Aluminum is also thought to act more directly, increasing the activity of certain immune cells, although this mechanism is not fully understood.
Although aluminum salts are not the only adjuvants on the market, vaccine manufacturers often prefer aluminum salts due to their long track record of safety data.
Whenever a new vaccine that uses an aluminum adjuvant is developed, long-term clinical trials are conducted to assess its safety and side effects are continuously monitored after approval. One of the earliest tests involving an aluminum adjuvant was published in 1934.
Subsequent trials revealed minor side effects, including redness at the injection site, body aches, and rare painful nodules. However, as Kennedy suggests, there is little reliable evidence that aluminum in vaccines causes serious long-term side effects.
People who are exposed to large amounts of aluminum on a daily basis (such as workers who breathe in aluminum dust or dialysis patients who regularly take aluminum-rich medications) have problems with their respiratory, bone, and nervous systems. You may experience system complications.
However, Dr. Michael Moody, director of the Duke Human Vaccine Institute, said the amount of aluminum in childhood vaccines is miniscule compared to what people are routinely exposed to in the environment and through food. Ta.
“We are exposed to aluminum all the time,” he said. “When you inhale dust from the outside, it comes into contact with the aluminum.”
During the first six months of life, babies are exposed to about 4.4 milligrams of aluminum through vaccines. In contrast, one slice of American cheese can contain as much as 50 milligrams of aluminum.
When scientists compared aluminum levels in the blood and hair of infants who received aluminum-containing vaccines and those who did not, they found no significant differences.
Some scientists believe that one potential side effect requires additional research.
In 2022, after a federally funded study found a small association between vaccine-induced aluminum exposure and asthma, the CDC noted that the link required “further investigation.” . (The agency said it would not change vaccine recommendations “based on a single study.”)
Kennedy, then president of the nonprofit Children's Health Defense, a frequent critic of vaccines, claimed the study was evidence that vaccinations were causing an “asthma epidemic.”
However, the authors were careful to point out the limitations of their findings, most notably that the effect was small and that the study was observational, meaning it could not prove cause and effect.
In their paper, the researchers cautioned that their results “do not provide strong evidence to question the safety of aluminum in vaccines.”
Independent experts also noted that the authors did not collect data on several important risk factors, such as whether participants were exposed to tobacco smoke or had a family history of asthma. Either of these could explain the observed differences.
In response to this study, a group of researchers from the Statens Serum Institute, a public health agency in Denmark, conducted a similar analysis on a national dataset of more than 450,000 children.
Their preliminary results did not show an association between aluminum adjuvants and asthma, they told the CDC's Advisory Committee on Immunization Practices in 2023.
Still, a CDC spokesperson said the agency is “discussing additional studies” to investigate the potential risks.
But until rigorous studies confirm the results, the link between aluminum and asthma is tenuous at best, said Dr. Stanley Plotkin, who played a central role in developing the rubella vaccine.
“You can't change the conclusions of a single paper,” he said. “You have to look at the entire literature.”
Anders Viid, who led the Danish study, said he welcomed further research into the safety of the adjuvant, but said these studies were by no means enough to convince skeptics that aluminum does not cause long-term side effects. He added that it might not be.
“I can't prove it's negative,” he said. “The goalposts will always move and you'll say, 'Oh, you didn't see this, you didn't see that that way.'