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“Does that have aluminum in it?” My patient asks. She practically spits out the word, aluminum. I have just finished cleaning the dog bites on both her hands, and I am much more concerned about what bacteria are in her wounds than the adjuvant in the TDaP booster I’ve just brought into the treatment room. “It does, yes. But it’s a tiny amount and is nothing compared to the aluminum you eat every day in your food.” I reply. “But… isn’t aluminum toxic?” she asks. “At very high and chronic doses, yes, but the amount in a vaccine is totally negligible.” I try to reassure her. I can tell she is not buying it, but we have discussed the importance of a booster given her current injury. She is fearful of tetanus (with good reason), and she was already overdue for a booster, so she decides to get the shot. But I can see that she’s still hesitant. I finish bandaging her hands and we leave the room. Like many patients with bite wounds, she takes the recommended prophylactic antibiotics without any question of risks/benefits, which I will always find somewhat ironic.
I understand it. Injections are not fun. They are scary, hurt, and make your arm sore the next day. They protect us from diseases you have probably never seen (if you are lucky), and words like “adjuvants” and “excipients” sound like fake species from a science fiction novel. Who wants to be injected with aluminum? That sounds bad. But the question becomes: is the content of aluminum in vaccines a toxicity risk?
Aluminum in vaccinations
Why is there aluminum in some vaccines? Because it makes them more effective! The aluminum binds to and increases the local response to the antigens in vaccines to create a longer-lasting immune reaction. In addition, the aluminum helps to hold the antigens at the site of injection so they are not absorbed or broken down too quickly for the immune system to make antibodies [1]. This type of additive is known as an adjuvant.
It’s also important to understand that aluminum is ubiquitous in our environment. Whether it’s from the soil, air, water or food, we are constantly exposed to aluminum to varying degrees [2]. Aluminum is the third most common metal in the earth’s crust, which makes avoiding environmental exposure practically impossible.
So, does the amount of aluminum in vaccinations stack up against our daily background exposure, and is there potential for intramuscular injections containing aluminum to cause harm? To investigate, we will do the math for a hypothetical newborn. For the sake of this example, he or she will be a normal healthy baby with no health issues at birth, and will be vaccinated as recommended at the CDC intervals. Let’s look at approximate aluminum exposures from several sources over the course of the first 12 months (numbers from CDC [3] and EPA [4]).
Breast milk: 8.5 mg over the course of a year.
Food: (assuming solid foods introduced at 6 months old) 0.7 mg per day. That results in 255 mg per year.
Air: from 0.0072 mg (rural environment) 0.36 mg per year (urban environment).
Water: 0.07 mg per liter. Yearly exposure variable based on weaning.
Vaccines: 4.6 mg
It is important to note that depending on the route, absorption and bioavailability will differ. This is the key to understanding the true level of exposure: Less than 1% of ingested aluminum from food is absorbed [5], while about 2% of inhaled aluminum will be [6]. Intramuscular aluminum is eventually 100% absorbed, but not all at once. The process happens very slowly. Recall that the reason aluminum is used in vaccines is to hold antigen in place while the immune system is activated, it tends to stay in the muscle tissue.
Studies have shown that around 17% of intramuscular aluminum is absorbed over a 28 day period following vaccination [7]. This exposure equates to between roughly 1.4 – 8.0 micrograms (0.0014 to 0.08 mg) per day [2]. This means that aluminum from vaccination is absorbed slowly into the blood over a long period of time and will fall well below the “minimum risk level” (the level of aluminum below which there is essentially no toxicity risk, as defined by the Agency for Toxic Substances and Disease Registry [ASTDR]).
From Yokel, Robert A., and Patrick J. Mcnamara. “Aluminium Toxicokinetics: An Updated MiniReview.” Pharmacology & Toxicology, vol. 88, no. 4, July 2008, pp. 159–167.
Furthermore, the aluminum used in vaccines is found in an insoluble form (either aluminum hydroxide or aluminum phosphate) both of which, once absorbed, are bound to carrier proteins and readily excreted by the kidneys shortly after exposure [2]. Given this information we can see that any injected aluminum will be released from muscle tissue at a gradual pace; one at which the body will typically have no difficulty clearing it from the blood.
Aluminum Safety
So we can establish the approximate exposures and bioavailability of aluminum from both vaccines and the environment. But is aluminum from vaccines dangerous?
Aluminum has been used as an adjuvant since 1926, and there have been many billions of doses of aluminum-containing vaccines over the last 90 years [8]. As such, if aluminum toxicity was a common occurrence — or even a relatively uncommon one — we should expect to see epidemiological data showing an increase in cases of toxicity following vaccination. This connection has never been established.
Aluminum toxicosis is typically only found in individuals whose jobs place them in constant contact with aluminum (e.g.: welders), or those with severe renal disease [6]. Aluminum is cleared from organs and soft tissues readily, which results in low accumulation in body tissues. Even though accumulation is typically minimal, aluminum can always be detected because we are constantly exposed as previously discussed. One exception to note is bones, which will absorb small amounts of free-circulating aluminum and store it stably for years. Excessive exposure to aluminum can cause bone disease [7]. Aluminum can also accumulate in brain tissue, especially when it is present in certain forms, and at high levels in the blood [10].
The next thing to consider is the type of aluminum. The two most common forms of adjuvant aluminum are aluminum hydroxide and aluminum phosphate. “Alum” or potassium aluminum sulfate is no longer found in vaccines, but was used in the past. There are several studies that have shown neurotoxic effects [9], but these studies were conducted using aluminum hydroxide injected directly into the brain. Aluminum at the site of a vaccine does not make its way into the brain in any appreciable quantity for two reasons: it is insoluble and as such is absorbed slowly over time as discussed above, and we have a blood-brain barrier (BBB) which does not typically allow free-circulating aluminum into the brain. Of note is a study which showed that aluminum hydroxide did not cause disruption to the BBB, while aluminum chloride and aluminum lactate had the potential to increase BBB permeability [10]. This is not to say that zero aluminum can end up in brain tissue, but the amount is miniscule and is related to forms of aluminum which are different from the adjuvants in vaccines [11,12].
In the older (and no longer used) DPT vaccine, alum (potassium aluminum sulfate) was used as an adjuvant, which was known to cause complications in a very low percentage of those vaccinated [13]. Again, alum adjuvants are no longer used in vaccines, so these complications are immaterial to the topic of modern vaccines and aluminum exposure.
Additional studies have shown that extremely high doses of injected aluminum has been able to induce neurotoxicity in rats, but these studies exposed the animals to a soluble form of aluminum which was injected into the lining of their abdominal cavities, [14] or administered via drinking water with citric acid to enhance absorption [15]. The distinction here is that the aluminum used in vaccine adjuvants is neither soluble in water, nor injected directly into a body cavity. Again, we see no evidence of human neurotoxicity following vaccination [6].
Conclusions
There’s a lot of misinformation about vaccines, their efficacy, ingredients, and safety. It is an ever-changing landscape of information, and new research is being conducted frequently. As healthcare providers we have a responsibility to our patients and profession to base our recommendations on the best available evidence. The current evidence tells us two things: modern aluminum adjuvants are effective at improving immune response to vaccine antigens, and these adjuvants are well-tolerated as well as nontoxic at the doses found in vaccines. There is no reason to think that the aluminum content in childhood vaccines is harmful to healthy children. Furthermore, the protection from serious illnesses that vaccines provide far outweighs any hypothetical toxicity risks from adjuvants. Working diligently to reduce incidence of preventable disease is an imperative in naturopathic medical practice, and using adjuvants to enhance the immune system’s innate ability to naturally produce antibodies against disease-causing pathogens is a safe and essential improvement to vaccine efficacy
References:
[1} He, Peng, et al. “Advances in Aluminum Hydroxide-Based Adjuvant Research and Its Mechanism.” Human Vaccines & Immunotherapeutics, vol. 11, no. 2, 2015, pp. 477–488., doi:10.1080/21645515.2014.1004026.
[2] Yokel, Robert A., and Patrick J. Mcnamara. “Aluminium Toxicokinetics: An Updated MiniReview.” Pharmacology & Toxicology, vol. 88, no. 4, July 2008, pp. 159–167., doi:10.1111/j.1600-0773.2001.880401.x.
[3] “Toxic Substances Portal – Aluminum.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 21 Jan. 2015, www.atsdr.cdc.gov/toxprofiles/tp.asp?id=191&tid=34.
[4] U.S. EPA. Exposure Factors Handbook 2011 Edition (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/052F, 2011.
[5] Soni, Madhusudan G., et al. “Safety Evaluation of Dietary Aluminum.” Regulatory Toxicology and Pharmacology, vol. 33, no. 1, 2001, pp. 66–79., doi:10.1006/rtph.2000.1441.
[6] Krewski, D, et al. “Human Health Risk Assessment for Aluminium, Aluminium Oxide, and Aluminium Hydroxide.” Journal of Toxicology and Environmental Health. Part B, Critical Reviews., U.S. National Library of Medicine, www.ncbi.nlm.nih.gov/pubmed/18085482.
[7] Mitkus, Robert J., et al. “Updated Aluminum Pharmacokinetics Following Infant Exposures through Diet and Vaccination.” Vaccine, vol. 29, no. 51, 2011, pp. 9538–9543., doi:10.1016/j.vaccine.2011.09.124.
[8] Hogenesch, Harm. “Mechanism of Immunopotentiation and Safety of Aluminum Adjuvants.”Frontiers in Immunology, vol. 3, 2013, doi:10.3389/fimmu.2012.00406.
[9] Chusid, J G, et al. “Experimental Epilepsy in the Monkey Following Multiple Intracerebral Injections of Alumina Cream.” Bulletin of the New York Academy of Medicine., U.S. National Library of Medicine, Nov. 1953, www.ncbi.nlm.nih.gov/pubmed/13094324.
[10] Kim, Y S, et al. “Aluminum Induced Reversible Change in Permeability of the Blood-Brain Barrier to [14C]Sucrose.” Brain Research., U.S. National Library of Medicine, 9 July 1986, www.ncbi.nlm.nih.gov/pubmed/3730864.
[11] Priest, N. D., et al. “The Bioavailability of 26-Al-Labelled Aluminium Citrate and Aluminium Hydroxide in Volunteers.” BioMetals, vol. 9, no. 3, 1996, pp. 221–228., doi:10.1007/bf00817919.
[12] Priest, N. D. “The Biological Behaviour and Bioavailability of Aluminium in Man, with Special Reference to Studies Employing Aluminium-26 as a Tracer: Review and Study Update.” J. Environ. Monit., vol. 6, no. 5, 2004, pp. 375–403., doi:10.1039/b314329p.
[13] Sauer, Louis W. “Precautions In Pediatric Immunization Procedures.” Journal of the American Medical Association, vol. 152, no. 14, Jan. 1953, p. 1314., doi:10.1001/jama.1953.03690140022005.
[14] TaÃr, Kaddour, et al. “Aluminium-Induced Acute Neurotoxicity in Rats: Treatment with Aqueous Extract of Arthrophytum (Hammada Scoparia).” Journal of Acute Disease, vol. 5, no. 6, 2016, pp. 470–482., doi:10.1016/j.joad.2016.08.028.
[15] Colomina, M.teresa, et al. “Influence of Age on Aluminum-Induced Neurobehavioral Effects and Morphological Changes in Rat Brain.” NeuroToxicology, vol. 23, no. 6, 2002, pp. 775–781., doi:10.1016/s0161-813x(02)00008-6.
