Kennedy Intensifies Vaccine Criticism Lacking Scientific Evidence – KFF Health News
November 24, 2025
KFF Health News: Kennedy Sharpens Vaccine Attacks, Without Scientific Backing
As the federal government gears up for the next meeting of its Advisory Committee on Immunization Practices, Health and Human Services Secretary Robert F. Kennedy Jr. has ramped up his criticisms of aluminum vaccine components, which are commonly used to enhance the body’s immune response.
Kennedy, a long-time anti-vaccine activist now seeking public office, claims that aluminum adjuvants are neurotoxic and linked to conditions such as autism, asthma, autoimmune diseases, and food allergies.
However, scientific consensus presents a different perspective. Recent recommendations encourage parents to introduce peanut-containing foods to infants early, resulting in a decrease in peanut allergy incidence.
Since taking office, Kennedy has initiated reviews of vaccine ingredients, with aluminum being a primary focus. The discussion of “adjuvants and contaminants” is included in the vaccine advisory panel’s draft agenda.
A CDC webpage, which has long assured the public that vaccines do not cause autism, was updated on November 19 to state that studies have not definitively ruled out a link between vaccines and autism.
Kennedy has also criticized scientists who have published studies affirming the safety of aluminum adjuvants. In August, he condemned a significant Danish study that found no correlation between aluminum in vaccines and childhood diseases, labeling it a “deceitful propaganda stunt” and demanding its retraction. The Annals of Internal Medicine rejected his claims and stood by the study.
Regarding the upcoming advisory panel meeting, HHS spokesperson Emily Hilliard stated that ACIP “is independently reviewing the full body of evidence on adjuvants and other vaccine components to ensure the highest safety standards.”
The stakes are high, as Kennedy’s efforts to undermine aluminum are part of a broader strategy aimed at creating doubt about vaccine safety and challenging the National Vaccine Injury Compensation Program, which drug manufacturers argue is crucial for maintaining a stable vaccine market.
Researchers in infectious diseases, immunology, pediatrics, and epidemiology assert that the data clearly indicates aluminum adjuvants are safe. “Aluminum is the third most common element on the Earth’s surface,” noted Paul Offit, a pediatrician and director of the Vaccine Education Center at Children’s Hospital of Philadelphia. “We’re all exposed to aluminum all the time. The water we drink and the food we eat contain aluminum.”
Vaccines contribute only a minuscule amount of aluminum to the body—approximately 8 milligrams after the complete childhood vaccine schedule. Offit explained that over the first 18 years of life, individuals naturally ingest about 400 milligrams of aluminum from everyday sources.
“I don’t understand the concern,” said Rajesh Gupta, a former FDA vaccine scientist. “Aluminum is distributed throughout the body and is ultimately excreted by the kidneys in urine.”
How They Work
The aluminum in vaccines is not in the form of foil or metal; it consists of aluminum salts, such as aluminum hydroxide or aluminum phosphate, which enhance the vaccine’s effectiveness.
This process is similar to zinc in cold tablets: patients don’t consume chunks of metal but rather a zinc salt that dissolves safely in the body.
In vaccines, these aluminum salts provide an additional boost to the immune system, helping it recognize the target germ more effectively. When injected, the vaccine remains near the injection site, causing mild, short-lived inflammation that attracts immune cells. These cells then transport the vaccine antigen—a harmless piece of a virus or bacterium—to nearby lymph nodes, where the adjuvants help the body identify and eliminate the germ quickly.
Harm HogenEsch, a professor of immunopathology at Purdue University, explained that aluminum adjuvants are effective only when injected at the same site as the vaccine ingredient they are meant to enhance. If the two shots are given in different locations, “you don’t see that effect,” he said.
In response to Kennedy’s assertions, scientists acknowledge that anything acting as an adjuvant can potentially boost an allergic response. However, this does not imply that aluminum-adjuvanted vaccines are causing children to develop food allergies. Antigens in vaccines, such as the hepatitis B surface antigen or HPV proteins, are not allergens, and no food proteins are included in vaccines.
Animal Experiments
Kennedy’s claims regarding aluminum adjuvants creating allergies stem from animal studies. In these experiments, scientists intentionally sensitize rats or mice by injecting them with a food protein mixed with aluminum. While aluminum strengthens the immune response, it does not independently cause an allergy.
“That’s the basis for many experimental mouse models, where a food allergen is injected with an aluminum adjuvant to sensitize the mice,” HogenEsch said. “I’m not aware of any food antigen being included in vaccines, so I don’t see how this could happen.”
Ross Kedl, a professor of immunology and microbiology at the University of Colorado Anschutz School of Medicine, emphasized that there is no plausible mechanism for vaccines to induce a peanut allergy. “Someone would have had to mix peanut proteins into the actual vaccine prior to injection.”
Stefan H. E. Kaufmann, director emeritus at the Max Planck Institute for Infection Biology in Berlin, noted that results from mice often do not translate to humans, as “mice are much easier to induce allergic reactions than humans.” In other words, what appears dramatic in rodent studies does not necessarily apply to human immune systems.
It is crucial to differentiate how aluminum behaves in lab animals versus humans, Kaufmann added.
Human Studies
Beyond animal models and theoretical scenarios, scientists have rigorously examined large human datasets for any signs of harm. In 2023, a study by the Vaccine Safety Datalink, coordinated by the CDC, reported a slight increase in asthma among children with higher aluminum exposure before age 2; however, this association disappeared in further analyses.
“That paper faced significant criticism,” Offit stated. “When controlling for breastfeeding, the association between asthma and aluminum-adjuvant-containing vaccines vanished.”
“It should have never been published,” he added.
Kathy Edwards, professor emerita of pediatrics at Vanderbilt University, explained that false signals often arise when large databases are analyzed for numerous outcomes. “When you examine a hundred different factors, some may appear to show a signal purely by chance,” she said. “Kennedy’s assessment is prone to cherry-picking,” she added, emphasizing the need for a basic understanding of statistics for accurate interpretation.
Following the 2023 findings, CDC scientists reached out to Anders Hviid, head of epidemiology research at the Statens Serum Institut in Copenhagen, Denmark, to replicate the study.
“It makes perfect sense to replicate findings in different data sources,” Hviid remarked. His nationwide Danish study tracked 1.2 million children over two decades, utilizing linked national health registries that document every vaccination and diagnosis.
“Our healthcare system is quite egalitarian. It’s free, and there’s universal access. Everyone is included in these nationwide registers,” he explained. Their findings revealed no increased risk of conditions associated with higher aluminum exposure from vaccines.
Rare Bumps
Doctors have documented one genuine reaction to aluminum adjuvants: itchy nodules at the injection site, known as “pruritic granulomas.” These small bumps are so rare that most allergists and pediatricians may never encounter a single case.
This reaction “doesn’t lead to anything serious and is not associated with anything beyond local irritation,” Edwards noted.
Researchers believe these bumps represent a localized immune response—occurring only at the injection site, not a systemic allergy—distinct from immediate allergic reactions treated with antihistamines, such as those caused by food or insect stings, where histamine floods the system within minutes, leading to hives, swelling, or breathing difficulties. Kedl pointed out that this distinction often gets lost in public discussions.
Eliminating Aluminum Adjuvants
For many experts, the critical issue is not solely whether aluminum is safe, but the implications for the entire vaccine program if aluminum adjuvants were removed. Many modern vaccines, which rely on a single purified protein—such as those for diphtheria and tetanus toxoids, hepatitis B, and HPV—depend on adjuvants for efficacy.
Edwards stated that simply replacing aluminum with a different adjuvant is not feasible. “They’re all built on one another,” she explained. Once a vaccine has been proven effective and becomes standard care, new or updated versions are typically not tested against a placebo in individuals who should receive that vaccine. Instead, they are tested against the existing product, meaning each approval relies on the previous one.
Core childhood vaccines would likely need reformulation, and extensive clinical trials would have to be repeated to demonstrate the safety and efficacy of new products. Meanwhile, production gaps and shortages would need to be managed, potentially for years, as manufacturers and regulators start anew—all while diseases like whooping cough, hepatitis B, and HPV-related cancers gain more opportunity to spread.
“Aluminum adjuvants have hit the sweet spot in terms of effectively inducing a robust antibody response that protects against the diseases for which they are used, while also being very safe,” HogenEsch stated. “It would be quite frankly foolish to try to eliminate them.”
A Century of Safe Use
The DTaP, hepatitis B, and HPV vaccines all contain aluminum adjuvants and have been in use for nearly a century. Large-scale studies show no link between aluminum and systemic allergic diseases.
“We have had aluminum adjuvants in vaccines for decades,” Edwards remarked. “I have grandchildren. My grandchildren have received all their vaccines, and I do not worry about their safety.”
If aluminum is wrongly portrayed as a villain and vaccine uptake declines, experts caution that the consequences will be tangible: increased measles in schools, more meningitis in college dorms, and more young adults succumbing to cancers that HPV vaccinations could have prevented.
In their view, the real danger lies not in the trace amounts of a metal that children encounter daily, but in reversing the protection that aluminum-adjuvanted vaccines have provided for generations.
That’s the trade-off Offit hopes parents will recognize. “Choosing not to vaccinate is not a risk-free decision,” he stated. “It’s simply a choice to accept a different risk.”
KFF Health News is a national newsroom that produces in-depth journalism about health issues and is one of the core operating programs at KFF—an independent source of health policy research, polling, and journalism. Learn more about KFF.
November 24, 2025
KFF Health News: Kennedy Sharpens Vaccine Attacks, Without Scientific Backing
As the federal government gears up for the next meeting of its Advisory Committee on Immunization Practices, Health and Human Services Secretary Robert F. Kennedy Jr. has ramped up his criticisms of aluminum vaccine components, which are commonly used to enhance the body’s immune response.
Kennedy, a long-time anti-vaccine activist now seeking public office, claims that aluminum adjuvants are neurotoxic and linked to conditions such as autism, asthma, autoimmune diseases, and food allergies.
However, scientific consensus presents a different perspective. Recent recommendations encourage parents to introduce peanut-containing foods to infants early, resulting in a decrease in peanut allergy incidence.
Since taking office, Kennedy has initiated reviews of vaccine ingredients, with aluminum being a primary focus. The discussion of “adjuvants and contaminants” is included in the vaccine advisory panel’s draft agenda.
A CDC webpage, which has long assured the public that vaccines do not cause autism, was updated on November 19 to state that studies have not definitively ruled out a link between vaccines and autism.
Kennedy has also criticized scientists who have published studies affirming the safety of aluminum adjuvants. In August, he condemned a significant Danish study that found no correlation between aluminum in vaccines and childhood diseases, labeling it a “deceitful propaganda stunt” and demanding its retraction. The Annals of Internal Medicine rejected his claims and stood by the study.
Regarding the upcoming advisory panel meeting, HHS spokesperson Emily Hilliard stated that ACIP “is independently reviewing the full body of evidence on adjuvants and other vaccine components to ensure the highest safety standards.”
The stakes are high, as Kennedy’s efforts to undermine aluminum are part of a broader strategy aimed at creating doubt about vaccine safety and challenging the National Vaccine Injury Compensation Program, which drug manufacturers argue is crucial for maintaining a stable vaccine market.
Researchers in infectious diseases, immunology, pediatrics, and epidemiology assert that the data clearly indicates aluminum adjuvants are safe. “Aluminum is the third most common element on the Earth’s surface,” noted Paul Offit, a pediatrician and director of the Vaccine Education Center at Children’s Hospital of Philadelphia. “We’re all exposed to aluminum all the time. The water we drink and the food we eat contain aluminum.”
Vaccines contribute only a minuscule amount of aluminum to the body—approximately 8 milligrams after the complete childhood vaccine schedule. Offit explained that over the first 18 years of life, individuals naturally ingest about 400 milligrams of aluminum from everyday sources.
“I don’t understand the concern,” said Rajesh Gupta, a former FDA vaccine scientist. “Aluminum is distributed throughout the body and is ultimately excreted by the kidneys in urine.”
How They Work
The aluminum in vaccines is not in the form of foil or metal; it consists of aluminum salts, such as aluminum hydroxide or aluminum phosphate, which enhance the vaccine’s effectiveness.
This process is similar to zinc in cold tablets: patients don’t consume chunks of metal but rather a zinc salt that dissolves safely in the body.
In vaccines, these aluminum salts provide an additional boost to the immune system, helping it recognize the target germ more effectively. When injected, the vaccine remains near the injection site, causing mild, short-lived inflammation that attracts immune cells. These cells then transport the vaccine antigen—a harmless piece of a virus or bacterium—to nearby lymph nodes, where the adjuvants help the body identify and eliminate the germ quickly.
Harm HogenEsch, a professor of immunopathology at Purdue University, explained that aluminum adjuvants are effective only when injected at the same site as the vaccine ingredient they are meant to enhance. If the two shots are given in different locations, “you don’t see that effect,” he said.
In response to Kennedy’s assertions, scientists acknowledge that anything acting as an adjuvant can potentially boost an allergic response. However, this does not imply that aluminum-adjuvanted vaccines are causing children to develop food allergies. Antigens in vaccines, such as the hepatitis B surface antigen or HPV proteins, are not allergens, and no food proteins are included in vaccines.
Animal Experiments
Kennedy’s claims regarding aluminum adjuvants creating allergies stem from animal studies. In these experiments, scientists intentionally sensitize rats or mice by injecting them with a food protein mixed with aluminum. While aluminum strengthens the immune response, it does not independently cause an allergy.
“That’s the basis for many experimental mouse models, where a food allergen is injected with an aluminum adjuvant to sensitize the mice,” HogenEsch said. “I’m not aware of any food antigen being included in vaccines, so I don’t see how this could happen.”
Ross Kedl, a professor of immunology and microbiology at the University of Colorado Anschutz School of Medicine, emphasized that there is no plausible mechanism for vaccines to induce a peanut allergy. “Someone would have had to mix peanut proteins into the actual vaccine prior to injection.”
Stefan H. E. Kaufmann, director emeritus at the Max Planck Institute for Infection Biology in Berlin, noted that results from mice often do not translate to humans, as “mice are much easier to induce allergic reactions than humans.” In other words, what appears dramatic in rodent studies does not necessarily apply to human immune systems.
It is crucial to differentiate how aluminum behaves in lab animals versus humans, Kaufmann added.
Human Studies
Beyond animal models and theoretical scenarios, scientists have rigorously examined large human datasets for any signs of harm. In 2023, a study by the Vaccine Safety Datalink, coordinated by the CDC, reported a slight increase in asthma among children with higher aluminum exposure before age 2; however, this association disappeared in further analyses.
“That paper faced significant criticism,” Offit stated. “When controlling for breastfeeding, the association between asthma and aluminum-adjuvant-containing vaccines vanished.”
“It should have never been published,” he added.
Kathy Edwards, professor emerita of pediatrics at Vanderbilt University, explained that false signals often arise when large databases are analyzed for numerous outcomes. “When you examine a hundred different factors, some may appear to show a signal purely by chance,” she said. “Kennedy’s assessment is prone to cherry-picking,” she added, emphasizing the need for a basic understanding of statistics for accurate interpretation.
Following the 2023 findings, CDC scientists reached out to Anders Hviid, head of epidemiology research at the Statens Serum Institut in Copenhagen, Denmark, to replicate the study.
“It makes perfect sense to replicate findings in different data sources,” Hviid remarked. His nationwide Danish study tracked 1.2 million children over two decades, utilizing linked national health registries that document every vaccination and diagnosis.
“Our healthcare system is quite egalitarian. It’s free, and there’s universal access. Everyone is included in these nationwide registers,” he explained. Their findings revealed no increased risk of conditions associated with higher aluminum exposure from vaccines.
Rare Bumps
Doctors have documented one genuine reaction to aluminum adjuvants: itchy nodules at the injection site, known as “pruritic granulomas.” These small bumps are so rare that most allergists and pediatricians may never encounter a single case.
This reaction “doesn’t lead to anything serious and is not associated with anything beyond local irritation,” Edwards noted.
Researchers believe these bumps represent a localized immune response—occurring only at the injection site, not a systemic allergy—distinct from immediate allergic reactions treated with antihistamines, such as those caused by food or insect stings, where histamine floods the system within minutes, leading to hives, swelling, or breathing difficulties. Kedl pointed out that this distinction often gets lost in public discussions.
Eliminating Aluminum Adjuvants
For many experts, the critical issue is not solely whether aluminum is safe, but the implications for the entire vaccine program if aluminum adjuvants were removed. Many modern vaccines, which rely on a single purified protein—such as those for diphtheria and tetanus toxoids, hepatitis B, and HPV—depend on adjuvants for efficacy.
Edwards stated that simply replacing aluminum with a different adjuvant is not feasible. “They’re all built on one another,” she explained. Once a vaccine has been proven effective and becomes standard care, new or updated versions are typically not tested against a placebo in individuals who should receive that vaccine. Instead, they are tested against the existing product, meaning each approval relies on the previous one.
Core childhood vaccines would likely need reformulation, and extensive clinical trials would have to be repeated to demonstrate the safety and efficacy of new products. Meanwhile, production gaps and shortages would need to be managed, potentially for years, as manufacturers and regulators start anew—all while diseases like whooping cough, hepatitis B, and HPV-related cancers gain more opportunity to spread.
“Aluminum adjuvants have hit the sweet spot in terms of effectively inducing a robust antibody response that protects against the diseases for which they are used, while also being very safe,” HogenEsch stated. “It would be quite frankly foolish to try to eliminate them.”
A Century of Safe Use
The DTaP, hepatitis B, and HPV vaccines all contain aluminum adjuvants and have been in use for nearly a century. Large-scale studies show no link between aluminum and systemic allergic diseases.
“We have had aluminum adjuvants in vaccines for decades,” Edwards remarked. “I have grandchildren. My grandchildren have received all their vaccines, and I do not worry about their safety.”
If aluminum is wrongly portrayed as a villain and vaccine uptake declines, experts caution that the consequences will be tangible: increased measles in schools, more meningitis in college dorms, and more young adults succumbing to cancers that HPV vaccinations could have prevented.
In their view, the real danger lies not in the trace amounts of a metal that children encounter daily, but in reversing the protection that aluminum-adjuvanted vaccines have provided for generations.
That’s the trade-off Offit hopes parents will recognize. “Choosing not to vaccinate is not a risk-free decision,” he stated. “It’s simply a choice to accept a different risk.”
KFF Health News is a national newsroom that produces in-depth journalism about health issues and is one of the core operating programs at KFF—an independent source of health policy research, polling, and journalism. Learn more about KFF.
