Watch "Why Is Aluminum in Vaccines? Isn’t It Dangerous?" for more information.

Vaccine processing

In the past, it was thought that the full amount of aluminum from a dose of vaccine was quickly released into the blood. But it is now understood that the aluminum stays near the injection site and is released slowly over time as the vaccine is processed. This slow release is why vaccines that contain aluminum often cause soreness, pain and redness at the injection site. 

Studies have found that aluminum levels in blood do not detectably increase after receipt of vaccines. This slow release explains why.

While it would be expected that our bodies could process the periodic larger exposures on a vaccination day, this slow release may be reassuring for those concerned about large exposures to aluminum when multiple vaccines are given. 

Injection vs. ingestion of aluminum

Most vaccines are given as shots or injections. For this reason, all of the aluminum in the dose enters the body. When we eat, or ingest, food, most of the aluminum passes through the intestine without getting into the bloodstream. Less than 1% of aluminum from food reaches the bloodstream. This makes some people wonder about the difference between exposure to aluminum from vaccines compared to that introduced through foods. 

As described earlier, our bodies process aluminum in the same way, regardless of its source. That processing is done in the blood. Because of the daily exposures to aluminum in food compared with the occasional exposures from vaccines, the main source of aluminum in the blood is from our diet. If we compare the amounts of aluminum that reach the blood from food and all recommended vaccines, we find:

• Between birth and 23 months of age: Aluminum exposure from food is between 3 and 18 mg. That from vaccines is at most 4.4 mg.
• Between birth and 18 years of age: Aluminum exposure from food is 73 to 438 mg. That from all recommended vaccines is between 7 and 8 mg.

If an adult lives to 100 years of age and receives all recommended vaccines, the differences are even more dramatic. Between 19 and 100 years of age, they would be exposed to between about 400 and 2400 mg of aluminum in their food compared with less than 5 mg in vaccines. If we include vaccines recommended in the first 18 years of life, the total aluminum exposure over 100 years of life would be between 11 and 12 mg from vaccines and between 500 and 2,800 mg from food.

Watch "Is There a Difference Between Aluminum That Is Injected vs. Ingested?" for more information.

Health effects of aluminum

Our bodies process aluminum all the time because we are regularly exposed to it. So, most people do not have any health effects from exposure to aluminum.

When the health effects of aluminum have been studied, a few issues have been identified: 

• Kidney dialysis patients have developed disorders of the brain and bones due to the aluminum content in intravenous fluids and antacids following years of dialysis. The bone disease was due to poor absorption of phosphate in the presence of high quantities of aluminum. Better systems of dialysis have decreased the occurrence of these disorders. 
• Babies born prematurely have experienced health effects of too much aluminum because they were fed intravenously, and their kidneys were not fully functioning. Changes to the amounts of aluminum in intravenous fluids have decreased the likelihood of this condition. 
• Sometimes children taking large amounts of aluminum-based medications have also been found to suffer from bone disorders caused by too much aluminum.
• It has been suggested that some diseases involving the brain, such as Alzheimer's disease, are caused by aluminum accumulation in brain tissue. However, studies have not consistently found increased levels of aluminum. As such, it is possible that when high levels of aluminum are found, it is the result of tissue damage allowing for aluminum to more easily enter brain tissue rather than aluminum causing the disease. Further, when people with kidney disease developed disorders of the brain, their symptoms were different from those of people with Alzheimer’s disease.

In sum, negative health effects from aluminum exposure are most likely if two conditions are met. First, the person’s kidneys are not functioning properly. Second, they are continuously exposed to very large quantities of aluminum (well above the amounts in a typical diet).

Aluminum in vaccines and health

The amount of aluminum in vaccines is minimal compared with what we are exposed to on a daily basis. Aluminum-containing vaccines have been used for decades and have been given to more than 1 billion people without problem. But the safety of aluminum in vaccines has been studied to make sure it is safe, particularly as more vaccines became available. Here are a few examples of these efforts.

In spring 2000, the National Vaccine Program Office (NVPO) reviewed aluminum exposure from vaccines and determined that no changes to vaccine recommendations were needed based on aluminum content. The Global Advisory Committee on Vaccine Safety, part of the World Health Organization (WHO), has also reviewed this question and found no evidence of health risks that would require changes to vaccine policy. 

A 2026 systematic review of 59 studies by Pamela Doyon-Plourde and colleagues evaluated the safety of aluminum adjuvants. The review found no serious or long-term outcomes to health, including no evidence of a link between aluminum adjuvants and asthma, autism spectrum disorder or other chronic conditions.

Likewise, a 2025 study by Niklas Worm Andersson and colleagues in Denmark compared more than 1.2 million children based on their receipt of different quantities of aluminum in vaccines over the first two years of life. They looked at rates of 50 different chronic conditions and found no differences based on the amounts of aluminum the children were exposed to in vaccines.

In late 2022, a paper was published suggesting a possible association between aluminum in vaccines and later development of asthma. However, these data should be viewed with caution because of the way the study was designed. For example, the authors did not control for breastfeeding, among other differences. When breastfeeding was considered, the association went away. 

Similarly, some concerns have been raised about a condition called autoimmune/inflammatory syndrome induced by adjuvants (ASIA). This condition has been associated with the presence of a group of immune cells near the injection site, called macrophagic myofasciitis (MMF). However, MMF lesions have also been found in people who do not have symptoms of ASIA, so it is unlikely that aluminum deposits following vaccination are causing ASIA. Several of these studies have also had design limitations.

Taken together, these individual studies and comprehensive data reviews are reassuring when it comes to concerns about the safety of aluminum in vaccines. In the few instances where concerns were identified, the studies were small or had design limitations. On the other hand, robust studies and reviews of the literature as a whole have not found any concerning outcomes.

Summary

In sum, families should remember the following when it comes to aluminum in vaccines:

1. We are exposed to much more aluminum from other sources than vaccines, particularly our daily exposures from foods and drinks.
2. We know the situations when health issues arise from aluminum, and we know what the health effects look like. We don’t see those effects when children or adults receive all of the currently recommended vaccines.
3. We have about 100 years of experience with aluminum in vaccines, and even though the number of vaccines has increased over time, the amount of aluminum exposure from vaccines has decreased due to lower amounts of aluminum in individual vaccines and the use of combination vaccines.
4. We also have numerous studies in millions of people that have not identified any safety concerns related to aluminum in vaccines, including several that have looked for links between aluminum exposure and dozens of different chronic conditions.

References

Doyon-Plourde P, Chong J, Abrams EM, Pless R, Young K, Tunis M, and Zafack J. Aluminum Adjuvants in Vaccines and Potential Health E­ffects: Systematic Review. BMJ. 2026 Apr 11;393;e088921. The authors reviewed 59 studies that met inclusion criteria and were published before November 2025 to evaluate health outcomes following receipt of vaccines containing aluminum adjuvants. Each study’s certainty of evidence was evaluated using the GRADE system. The studies reviewed no causal associations between aluminum-adjuvanted vaccines and serious or long-term outcomes. The most common effect identified were local granulomas or nodules near the injection site, but these were uncommon (< 1%). They identified several studies of limited size and methodology, including those related to macrophagic myofasciitis.

Nirenberg E, Maldonado YA, and Hoffman SA. The Role and Safety of Aluminum Adjuvants in Childhood Vaccines. Pediatrics. 2026 Feb 25;157(3):e2025074874. The authors conducted a literature review and summarized the immunology, pharmacokinetics and safety of aluminum adjuvants. The evidence related to four health outcomes of concern was evaluated, including autism spectrum disorder, Alzheimer’s disease and neurotoxicity, allergic disease and asthma, and autoimmune disease. The authors found no consistent, reproducible evidence for any of these conditions. The paper also included data-informed responses to common questions that parents have about aluminum in vaccines. 

Moser CA and Offit PA. Aluminum Exposure from Vaccines and Diet. JAMA. 2026 Feb 9;335(11):939-942. The authors summarized aluminum exposure, processing and health effects. They described a brief history of the use of aluminum in vaccines, how it is processed, and maximum potential exposure to aluminum from vaccines recommended on the childhood and adult immunization schedules published in January 2025. They also estimated aluminum exposure from diet based on 2020 to 2025 dietary guidelines for children and adults. When they accounted for the low absorption rate of aluminum that is ingested, compared with the amount injected in vaccines, they found that in the first two years of life, infants are exposed to 3-18 mg of aluminum from diet compared with 4.4 mg from vaccines. During the first 18 years of life, dietary exposure was estimated at 73-438 mg, whereas amounts from vaccination would be 7.3-7.8 mg. Over 100 years of life, estimated dietary exposure would be between 468-2,785 mg, and vaccine exposure would be between 11.7-12.2 mg of aluminum.

Andersson NW, Bech Svalgaard I, Hoffmann SS, Hviid A. Aluminum-Adsorbed Vaccines and Chronic Diseases in Childhood: A Nationwide Cohort Study. Ann Intern Med. 2025 Jul 15. doi: 10.7326/ANNALS-25-00997. Epub ahead of print. Erratum in: Ann Intern Med. 2025 Jul 17. The authors examined the impact of varying amounts of aluminum exposure from vaccines in the first two years of life on several autoimmune and developmental outcomes. This cohort study included more than 1.2 million children in Denmark from 1997 to 2020. Children received anywhere from 0 mg to 4.5 mg of aluminum during that time, finding no statistically significant increases in risk for any of the outcomes they studied. Differences in aluminum content were associated with small changes in risk for some outcomes, but these outcomes tended to be slightly above or below 1, which is the risk associated with no difference between groups. For example, for some outcomes, larger amounts of aluminum “increased” the risk (1.02 for atopic dermatitis), and for other conditions it “decreased” the risk (0.96 for asthma and 0.93 for neurodevelopmental disorders). All conditions studied had hazard ratios that were close to 1.0, so the impact of any of these associations is likely very small. Likewise, for all conditions in which aluminum “increased” the risk (the hazard ratio was >1.0), the confidence intervals included 1.0, meaning they were not statistically significant. 

Goullé JP, Grangeot-Keros L. Aluminum and vaccines: Current state of knowledge. Med Mal Infect 2020 Feb;50:16-21.
Although aluminum at high doses can cause a variety of clinical manifestations, the quantity of aluminum in vaccines is too small to cause a direct toxic effect. Indeed, the quantity of aluminum in biological specimens from those receiving aluminum-containing vaccines is indistinguishable from unvaccinated subjects. The concern that aluminum in vaccines might be associated with a rare autoimmune disease called macrophagic myofasciitis has been refuted by previous studies.

Karwowski MP, Stamoulis C, Wenren LM, et al. Blood and hair aluminum levels, vaccine history, and early infant development: a cross-sectional study. Acad Pediatr 2018;18:161-165.
Children aged 9 to 13 months, excluding those who received aluminum-containing pharmaceuticals, were evaluated for blood and hair aluminum levels, vaccination history, and cognitive, language and motor development scores. The authors found no correlation between infant blood or hair aluminum concentrations and vaccine history or between blood aluminum and overall developmental status.

Ameratunga R, Gills D, Gold M, et al. Evidence refuting the existence of autoimmune/autoinflammatory syndrome induced by adjuvants (ASIA). J Allergy Clin Immunol Pract 2017;5:1551-1555.
The authors identified two studies refuting the claim for autoimmune/autoinflammatory syndrome induced by adjuvants (ASIA) as suggested by Shoenfeld and coworkers. In one study, lupus patients were found to have no increase in exacerbations after receiving a hepatitis B vaccine containing an aluminum adjuvant. A second study evaluated the incidence of autoimmune disease in more than 18,000 patients who received subcutaneous allergen-specific immunotherapy containing large quantities of injected aluminum. Patients receiving injected aluminum were found to have a lower incidence of autoimmune disease compared with controls. The authors concluded that current studies do not support the existence of ASIA.

Mitkus RJ, King DB, Hess MA, et al. Updated aluminum pharmacokinetics following infant exposures through diet and vaccination. Vaccine 2011; 29:9538-9543.
The authors found that the burden of aluminum from diet and from vaccines given according to the CDC schedule within the first year of life was well within levels considered to be safe, even when the infant was small for age (i.e., equal to or less than the 5thpercentile for weight).

Jefferson T, Rudin M, Di Pietrantonj C. Adverse events after immunization with aluminum-containing DTP vaccines: systematic review of the evidence. Lancet Infect Dis 2004;4:84-90. The authors reviewed the incidence of adverse events after exposure to aluminum-containing diphtheria, tetanus and pertussis (DTP), alone or in combination, compared with identical vaccines, either without aluminum or containing aluminum in different concentrations. In children up to 18 months of age, aluminum-containing vaccines were associated with more erythema and induration than vaccines without aluminum. They were not, however, associated with serious adverse events.

Keith LS, Jones DE, Chou CHSJ. Aluminum toxicokinetics regarding infant diet and vaccinations. Vaccine 2002;20:S13-S17.
The authors determined whether exposure to aluminum in the diet and in vaccines during the first year of life exceeded the minimal risk level (MRL) set by the Agency for Toxic Substances and Disease Registry (ATSDR). They found that the amount of aluminum received from vaccines was greater than that from dietary sources; however, this level was routinely below the MRL with the exception of brief periods immediately following vaccination. Levels of exposure slightly above the MRL were also likely to be safe given the manner in which the MRL is calculated.

Reviewed by Paul A. Offit, MD, on June 4, 2026