Robert F.Kennedy Jr. He has often oriented his criticisms of vaccines on a common ingredient: aluminum, which according to him is responsible for a series of childhood disorders, including food allergies, autism and depression.
“You wonder why a whole generation of children is allergic to things,” said Mr. Kennedy during an interview from 2021. “It is because we induce allergies, filling them with aluminum.”
For many scientists specialized in vaccines, aluminum is a strange target. It is among the most studied ingredients in vaccines and perhaps in modern medicine.
“There is a huge amount of information collected,” said Dr. Andrew Racine, pediatrician and medical director of Montefiore Health System. “If there was something that jumps to the eye about the lack of security, most likely we would have seen it somewhere, and simply does not seem.”
Aluminum salts, a more soluble form of the metal, are added to vaccines such as TDAP injection to strengthen the body’s immune response. The ingredient has been evaluated several times as part of the vaccines in clinical studies and administered in billions of doses for several decades.
Even so, while Kennedy is preparing for confirmation hearings as secretary of health and human services, many experts fear that the stand-by will face a new exam and could even serve as a justification to limit access to different childhood vaccines, Like vaccines for hepatitis B. and pneumococcal disease.
Aaron Siri, a lawyer and close ally of Kennedy, represented customers in the petition to federal regulators to suspend the distribution of more than a dozen vaccines until the producers had provided more information on the amount of aluminum in the formulations.
Mr. Kennedy and Mr. Siri did not respond to requests for comment.
The origins of aluminum added in vaccines can be traced back to almost a century ago. In a stable on the outskirts of Paris, a young veterinarian had made a curious discovery: mixing the tapioca with vaccines against the diphtheria of his horses made them more effective.
The doctor Gaston Ramon had noticed that the horses that had developed a slight infection at the point of the injection had a much stronger immunity against the diphtheria. He theorized that adding something to his injections that caused inflammation – ingredients that he later called adiuvanti, derived from the Latin root “help” – helped to induce a stronger immune response.
After testing several candidates – including breadcrumbs, Vaseline and rubber latex – he found success with a tapioca injection, which produced a slight swelling and many more antibodies.
Tapioca has never taken hold as an adherent. But in 1932, a few years after the publication of Dr. Ramon’s studies, the United States began to include aluminum salts in vaccinations against diphtheria, since it was discovered that they caused a similar but more reliable effect.
Today, the adiuvants of aluminum are in 27 routine vaccines and in almost half of those recommended for children under 5 years.
This further immune enhancement is not necessary in all types of vaccines. The vaccines that contain a weakened form of a virus, such as measles, parotitis and rubella vaccine, or created with MRNA technology, such as Pfizer vaccines and modern Covid-19, generate sufficiently strong immune responses.
But in vaccines that contain only small fragments of the pathogen, which would attract little attention from the immune system, the adiuvants help to stimulate a stronger response, allow the administration of vaccines in minor doses.
Scientists believe that aluminum salts work in two ways. First of all, aluminum is linked to the main component of the vaccine and causes its diffusion in the bloodstream more slowly, giving the immune cells more time to build an answer.
It is also believed that aluminum acts more directly, improving the activity of some immune cells, although this mechanism is not completely understood.
Although aluminum salts are not the only adjuvant on the market, vaccine producers often prefer them due to a long experience of safety data.
Every time a new vaccine is developed that uses an aluminum adjuvant, it is subjected to long clinical studies to evaluate its safety and the side effects are continually monitored after approval. One of the first studies that included an aluminum adjuvant was published in 1934.
Subsequent studies have revealed some minor side effects, such as redness, muscle pain and, in rare cases, painful nodules on the injection site. But there is few credible tests that aluminum in the vaccines causing serious side side effects in the long term, as Kennedy suggested.
People who are usually exposed to large quantities of aluminum – such as workers who breathe aluminum powder or patients in dialysis who usually receive aluminum rich drugs – can manifest respiratory, bone and neurological complications.
The amount of aluminum in child vaccines, however, is negligible compared to the one to which people are usually exposed through the environment and food, said Dr. Michael Moody, director of the Duke Human Vaccine Institute.
“We are constantly exposed to aluminum,” he said. “If the dust from the outside, come into contact with the aluminum.”
In the first six months of children’s lives, vaccines expose them to about 4.4 milligrams of aluminum. A slice of American cheese, on the contrary, can contain up to 50 milligrams of aluminum.
When scientists compared the aluminum levels in the blood and hair of the children who had been administered vaccines containing aluminum compared to those who had not been administered, they did not find significant differences.
Some scientists believe that a potential side effect requires further research.
In 2022, after a study financed by the Federal Government found a minor association between exposure to aluminum from vaccines and asthma, the CDC observed that the connection justified “further investigations”. (The agency said that it will not change the recommendations on vaccines “on the basis of a single study”.)
Mr. Kennedy, who was then president of the Children’s Health Defense, a often critical non-profit organization against vaccines, presented the study as proof that vaccinations were causing an “asthma epidemic”.
But the authors of the article were careful to underline the limits of their discoveries, in particular that the effect was small and that the study was observational, which means that it cannot demonstrate cause and effect.
In the document, they warned that their results “do not constitute a strong test to question the safety of aluminum in vaccines”.
Independent experts also noticed that the authors did not collect data on several key risk factors, as if the participants were exposed to cigarette smoking or had a family story of asthma, both who could explain the difference observed.
In response to the study, a group of researchers from the Statens Serum Institut, the Danish public health agency, has conducted a similar analysis on a national data set of over 450,000 children.
Their preliminary results did not show an association between aluminum adjuvants and asthma, they declared the CDC’s immunization practices in 2023 to the consultative committee.
However, a spokesman for the CDC said that the agency is “discussing further studies” to investigate the potential risk.
But until a rigorous research can confirm the discovery, the link between aluminum and asthma will be, at best, tenuous, said Dr. Stanley Plotkin, who played a fundamental role in creating the vaccine against Rosalia.
“It is not possible to change the conclusions of a single article,” he said. “You have to look at general literature.”
Anders Hviid, who conducted the Danish study, said he welcomed further research on the safety of the adiuvants, but added that these studies may never be sufficient to convince the skeptics that aluminum does not cause long -term side effects.
“It is not possible to demonstrate a negative,” he said. “There will always be this pole of the door that moves, saying: ‘Well, you didn’t look at this and you didn’t look at that in that way.'”