Pediatric Annals

Healthy Baby/Healthy Child 

Aluminum in Vaccines: Addressing Parents' Concerns

Sabrina Fernandez, MD

Abstract

With myriad frightening stories on the Internet about vaccines, parents are frequently presenting to the pediatrician with questions about the safety of vaccine ingredients, and pediatricians need to be ready to listen to families with a kind ear. Pediatricians must also feel prepared to offer thoughtful, knowledgeable advice, appreciating the parent's concerns and educating them about the irrefutable benefits as well as the potential risks of vaccination. [Pediatr Ann. 2016;45(7):e231–e233.]

Abstract

With myriad frightening stories on the Internet about vaccines, parents are frequently presenting to the pediatrician with questions about the safety of vaccine ingredients, and pediatricians need to be ready to listen to families with a kind ear. Pediatricians must also feel prepared to offer thoughtful, knowledgeable advice, appreciating the parent's concerns and educating them about the irrefutable benefits as well as the potential risks of vaccination. [Pediatr Ann. 2016;45(7):e231–e233.]

I recently had a new couple meet me for a prenatal visit. Their baby girl was to be born in a few months, and they were eager to meet their new pediatrician and prepare themselves for their baby's arrival. They had the usual round of questions: “How often are you in the clinic?” “How do we contact your office in the middle of the night?” “What is the schedule of visits for a newborn?” Then they asked a question that seemed a little out of the blue: “What do you think about aluminum in vaccines? We've been doing some research and we are wondering if it's safe for the baby?” The answer to the question is the focus of this article.

Why Is There Aluminum in Vaccines?

Aluminum has been present in vaccines since 1926.1 Aluminum is a vaccine adjuvant, which is a compound added to a vaccine to increase its immunogenicity. It is postulated that adjuvants help stimulate antigen-presenting cells, induce chemokines, and activate complement.2 Effectively, aluminum makes vaccines work better, reducing the quantity of shots required for the same vaccine or reducing the amount of antigen needed in the vaccine. Aluminum in vaccines comes in the form of a salt, such as aluminum hydroxide or aluminum phosphate. Aluminum is found in the following vaccines: hepatitis A, hepatitis B, Haemophilus influenzae type b, pneumococcal vaccines, and diphtheria-containing vaccines (such as diptheria-tetanus-acellular pertussis). The amount contained in each vaccine ranges from 0.125 to 0.85 mg per dose3 (Table 1).


            Quantity of Aluminum in Vaccines

Table 1.

Quantity of Aluminum in Vaccines

What Are the Side Effects of Aluminum?

There are known mild side effects associated with vaccines and aluminum. A recent review of studies of aluminum-containing diphtheria, tetanus, and pertussis vaccines found significantly more erythema and induration compared to plain vaccines in young children, but significantly fewer reactions of all types studied. This refers to reactions experienced in the first 24 hours, including local skin reactions, crying, fevers, vomiting, drowsiness, and rash. In older children in the same review, there were no differences in induration, swelling, or temperature elevation, but there was an association with local pain lasting up to 2 weeks. There was no evidence found that aluminum in vaccines caused any long-term or serious adverse events.1 These side effects—erythema, induration, and pain at the injection site—are transient, mild, and known reactions of many vaccines.

Serious adverse events related to aluminum have mainly been observed with large doses or in patients with underlying disease. There are historic cases of patients with kidney failure receiving aluminum in their dialysate solutions before dialysis systems were more refined. These patients had a neurologic disease known as dialysis dementia. There are also reports of late development of muscle nodules, termed “macrophagic myofasciitis,” forming 3 years after exposure to aluminum in vaccines. This was reported primarily in patients with compromised immune systems. Lastly, in otherwise healthy patients who chronically ingest antacids, aluminum can bind intestinal phosphorus and prevent its absorption into bone, resulting in pathologic fractures.4 There have also been suggestions that certain neurologic diseases such as Alzheimer's disease are caused by aluminum accumulation in the brain. However, these studies do not consistently find increased levels of aluminum in patients with Alzheimer's disease.3 Therefore, serious events after aluminum exposure are mainly associated with serious underlying disease or large doses, neither of which applies to the vaccination of healthy infants.

How Much Aluminum Are We Exposed to on a Regular Basis?

Aluminum is naturally found in the soil, water, and air. It is the third most common element on the earth's crust, behind oxygen and silicon.4 It is present in products such as aluminum foil and beverage cans (Figure 1), antiperspirants and antacids, and even in breast milk and infant formula (Table 2).3,4 It is also found in foods, including fruits, vegetables, beer, wine, flour, cereal, nuts, and honey. Adults typically ingest 7 to 9 mg of aluminum per day.3


            Aluminum is ubiquitous in the environment, including in everyday products such as soda cans.
            © Shutterstock

Figure 1.

Aluminum is ubiquitous in the environment, including in everyday products such as soda cans.

© Shutterstock


            Quantity of Aluminum in Foods and Medicines

Table 2.

Quantity of Aluminum in Foods and Medicines

How Much Aluminum Is Safe for Babies?

Federal regulations for vaccines limit the amount of aluminum to no more than 0.85 to 1.25 mg per dose.5 The pneumococcal vaccine, for example, has 0.125 mg of aluminum per dose, approximately one-tenth of the maximum recommended dose. Taking into account all the vaccines recommended by the Centers for Disease Control and Prevention, the maximum amount of aluminum a baby is exposed to in the first year of life from vaccines is 4.225 mg,5 which is approximately one-half the estimated daily dietary intake (7–9 mg) by adults.3 Therefore, the amount of aluminum in vaccines is tiny compared to what we ingest every day. However, many parents wonder if there is a difference between ingestion and injection.

Ingestion Versus Injection

To understand the difference between ingestion and injection of aluminum, it is first necessary to understand the absorption and elimination of aluminum in the body. Aluminum is inhaled or absorbed from the gut or muscle into the bloodstream, then stored in many tissues including the lungs and bone. Although the body eliminates aluminum, its storage outpaces the elimination, and the resulting overall accumulation is termed the “total body burden of aluminum.” Dietary aluminum is present in breast milk, infant formula, and various foods. Therefore, infants accumulate aluminum in their bodies slowly over time. Additionally, infants are also born with small amounts of aluminum from in-utero exposure. Injections of aluminum contained in vaccines are different from dietary sources because the doses are given only a few times over the infant's first year of life, whereas dietary sources of aluminum accumulate slowly every day. Based on animal models, these injections of aluminum salts are only partially absorbed into the bloodstream, at 17% for aluminum hydroxide and 51% for aluminum phosphate.6 The absorption process for injected aluminum also takes time, which can vary from weeks to months depending on the type of aluminum salt used.

The minimum risk level (MRL) is the level of aluminum at which no observed adverse effects have been found. This MRL is established by the Agency for Toxic Substances and Disease Registry. The MRL for infants is estimated at 1 mg/kg of body weight per day. The MRL increases with time because aluminum in the body is stored more readily than it is eliminated, and children's weights increase with time.Taking into account both injections of aluminum-containing vaccines as well as the daily intake of dietary aluminum, the total body burden of aluminum never rises above the MRL in the first year of life, even estimating for small infants (5th percentile for weight) and using vaccines with the most aluminum per dose.6 This should be reassuring for pediatricians and families, knowing that the amount of aluminum in vaccines is miniscule, and far below the established risk level. Additionally, for the many infants who receive different formulations of vaccines and less than the maximum dose of aluminum, the risk is even lower.

The Bottom Line

Vaccination is perhaps the single most successful preventive health measure of all time. Parents and families have concerns about vaccine ingredients that pediatricians must feel comfortable addressing. The next time parents ask about aluminum in vaccines, remember this: the latest statistical models for the absorption and elimination of both ingestable and injectable aluminum estimate that an infant's total body burden of aluminum never exceeds the MRL. Taking these data into account, along with the extensive safety record of aluminum-containing vaccines over the last 90 years with hundreds of millions of people receiving aluminum-containing vaccines,7 and the overwhelming benefits of vaccines in preventing deadly diseases, the benefit-to-risk ratio seems indisputable (Table 3).


            Take-Home Points

Table 3.

Take-Home Points

References

  1. Jefferson T, Rudin M, Di Pietrantonj C. Adverse events after immunisation with aluminium-containing DTP vaccines: systematic review of the evidence. Lancet Infect Dis. 2004;4(2):84–90. doi:10.1016/S1473-3099(04)00927-2 [CrossRef]
  2. Eickhoff TC, Myers M. Workshop summary: aluminum in vaccines. Vaccine. 2002;20(Suppl 3):S1–S4. doi:10.1016/S0264-410X(02)00163-9 [CrossRef]
  3. The Children's Hospital of Philadelphia. Vaccine ingredients - aluminum. http://www.chop.edu/centers-programs/vaccine-education-center/vaccine-ingredients/aluminum. Accessed June 14, 2016.
  4. Keith LS, Jones DE, Chou CH. Aluminum toxicokinetics regarding infant diet and vaccinations. Vaccine. 2002;20(Suppl 3):S13–S17. doi:10.1016/S0264-410X(02)00165-2 [CrossRef]
  5. US Food and Drug Administration. Study reports aluminum in vaccines poses extremely low risk to Infants. http://www.fda.gov/BiologicsBloodVaccines/ScienceResearch/ucm284520.htm. Accessed June 14, 2016.
  6. Mitkus RJ, King DB, Hess MA, Forshee RA, Walderhaug MO. Updated aluminum pharmacokinetics following infant exposures through diet and vaccination. Vaccine. 2011;29(51):9538–9543. doi:10.1016/j.vaccine.2011.09.124 [CrossRef]
  7. Offit PA, Jew RK. Addressing parents' concerns: do vaccines contain harmful preservatives, adjuvants, additives, or residuals?Pediatrics. 2003;112(6 pt 1):1394–1397. doi:10.1542/peds.112.6.1394 [CrossRef]

Quantity of Aluminum in Vaccines

Vaccine Quantity of Aluminum
Pneumococcal 0.125 mg/dose
DTaP <0.17–<0.625 mg/dose
Hib 0.225 mg/dose
Hib/Hep B 0.225 mg/dose
Hep A 0.225–0.25 mg/dose (pediatric dose)
Hep B 0.225–0.5 mg/dose
Hep A/Hep B 0.45 mg/dose
DTaP/IPV/Hep B <0.85 mg/dose
DTaP/IPV/Hib 0.33 mg/dose

Quantity of Aluminum in Foods and Medicines

Food/Medicine Quantity of Aluminum
Breast milk 0.04 mg/L
Infant formula 0.225–1.15 mg/L
Antacid 104–208 mg/tablet
Buffered aspirin 10–20 mg/tablet

Take-Home Points

Aluminum is the third most abundant element on the earth's crust, behind oxygen and silicon, and is the most common metal. It is present in lakes and ponds, in the air, and in everyday foods including infant formula, breast milk, fruits, and vegetables

Aluminum has been present in vaccines since 1926, giving us 90 years of experience with it as a vaccine adjuvant. It helps vaccines work better, stimulating the immune system to make more antibody against the antigen

Adverse effects of aluminum in patients have been described, but these are largely in patients with underlying disease such as renal dysfunction, or with large amounts of exposure to aluminum that are far greater than that contained in vaccines

The latest statistical models, which incorporate estimations of aluminum absorption from injection, as well as estimations of the time it takes to absorb from the muscle to the bloodstream, show that the total body burden of aluminum in infants never exceeds the minimum risk level

Parents and pediatricians should feel comfortable discussing the safety and benefits of aluminum in vaccines

Authors

Sabrina Fernandez, MD

 

Sabrina Fernandez (formerly Santiago), MD, is a Primary Care Pediatrician, University of California San Francisco, Benioff Children's Hospital; and an Assistant Professor of Pediatrics, Department of Pediatrics, University of California San Francisco.

Address correspondence to Sabrina Fernandez, MD, via email: sabrina.fernandez@ucsf.edu.

Disclosure: The author has no relevant financial relationships to disclose.

10.3928/00904481-20160606-01

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