As I was saying in my previous post, Dr. Bob Sears, in The Vaccine Book, is very concerned about the amount of aluminum in the current vaccine schedule. So concerned, in fact, that he’s made up an alternative vaccination schedule to – so he claims – expose the child to less vaccine-derived aluminum at any one time and prevent possible neurological damage as a result of aluminum poisoning.
He bases his aluminum-related worries on a lack of research regarding safe levels of injected aluminum, and a number of studies in the medical literature dealing with:
1) harm from aluminum in people with kidney disease (who have trouble excreting aluminum from the water they drink and medical preparations they’re given), which happens over a period of months to years of constant aluminum administration
2) Premature infants given aluminum-containing intravenous nutrition who developed signs of slight neurotoxicity when it was administered continuously over a period of weeks
3) animal and/or in vitro cell studies, in which very large amounts of aluminum were administered over a period of time which showed either cellular damage or elevated brain aluminum.
Sears concedes that none of these scenarios really correlates well to a term baby given vaccines via the intramuscular/subcutaneous route, in discrete events that occur months apart from one another. Despite this, he is concerned that the growing amounts of aluminum in the current vaccine schedule are putting babies in danger of brain damage, and thus recommends his trademark alternative vaccine schedule, which necessitates many more visits (not to mention many more needles!) and schleps out those vaccines normally given in the first two years of life, over six of them. We’ll be discussing other aspects of this alternative schedule in a future post, but right now I want to concentrate on the presumption of guilt Sears attaches to the aluminum levels in the current vaccine schedule, and whether what we know about how aluminum behaves in the body warrants such a presumption. And whether spreading out vaccines over several months, as opposed to bunching 2-3 up every few months, really matters all that much.
There is one thing on the subject of aluminum that Sears and I agree upon, so I might as well say it right up front: there is an acute need for more research, specifically regarding the pharmacodynamics of intramuscular aluminum administration in humans and determining the toxic threshold for IM injections. This doesn’t mean aluminum should be held guilty until proven innocent; however, the research would be considerably easier to carry out than the thimerosal studies, we (by this I mean the scientific/medical community) owe it to the public to have this more precise knowledge, and the concept of aluminum becoming “the new thimerosal”, as Sears likes putting it, badly needs to be nipped in the bud. I’ll be discussing this issue in more detail towards the end of this blogpost. In the meantime, let’s look at what is already known.
This is a really complicated subject to wrap one’s brain around, even if one has a background in biology, chemistry and/or phsiology; therefore, I will try and provide as much details and explanations as I can. If anyone better-versed than I in the subject spots mistakes of math or substance, please let me know.
Fast Facts about Aluminum
Aluminum is the third most common element on Earth, and the most abundant metal. It has no known biological function, but it’s in everything – air, water, food etc. Everybody accumulates aluminum in their body throughout life, most of it in our bones, but with smaller amounts present in the kidneys, liver, fatty tissue, lymphatic system, and brain. Actually, everybody starts accumulating it in utero, as it crosses the placenta from the mother’s bloodstream. Hence, all of us are born with a certain amount of aluminum in our bodies. Aluminum exits the body primarily via urine, and is also excreted via bile into the gut.
The aluminum isotope in nature is 27Al; since 1990, another isotope – 26Al – has been manufactured. While expensive, it enables researchers to give a test subject a given dose of aluminum and both see and quantify where it goes in the body and when it leaves the body, either by measuring its level in body fluid or tissue samples or by doing a whole-body scan with an accelerator mass spectrometer. The latter may be expensive and technically difficult, but it beats taking biopsies from living humans’ brains, livers and bones.
Normal aluminum blood levels are ~5-10mcg/L (or ng/ml, which is the same thing). People with renal failure can have much higher blood levels – about 50mcg/L – and show no signs of toxicity. Increased potential for toxic symptoms starts at around 100mcg/L, though in children the level might be somewhat lower (Sears points this out by referencing this paper).
I shouldn’t really need to say this, but attempting to determine body aluminum levels via hair analysis is the hallmark of a quack.
Most of the aluminum in our bodies enters it through the digestive tract. The average adult ingests 3-8mg of aluminum daily; however, only 0.1-1% (i.e, 3-80mcg) is absorbed into the bloodstream. The absorbed aluminum is distributed in the various tissues. Priest’s review on the subject of bioavailibility of aluminum (keep the link open in another tab, as we’ll be referring to it again) has a table depicting where aluminum accumulates in the body, and in what proportions (click on the thumbnail to see the full-size table):
Note that the central nervous system takes up only about 1% of the total aluminum in the body (emphasized). This fraction is the one that concerns us when talking about potential neurotoxic effects.
Aluminum neurotoxicity occurs almost exclusively in people on dialysis (dialysis encephalopathy) or ones with a very prolonged and increased occupational exposure. It takes, even in such people, constant, increased exposure over a period of months to develop. Symptoms begin with confusion, poor coordination and abstract reasoning and poor memory and progress to paranoia, hallucinations, convulsions and eventually death. The treatment in people without renal failure is to stop administering aluminum; in dialysis patients or those with severe toxicity, a chelator, desferroxamine, can be used. Preemies given high-aluminum parenteral (intravenous) nutrition for long periods of time have shown decreased IQs as compared to those given low-aluminum nutrition in one study, however their blood and urine levels were not tested. And despite the rumors, aluminum exposure almost certainly does not cause Alzheimer’s disease.
Aluminum compounds as vaccine adjuvants
Aluminum compounds have been used as vaccine adjuvants (substances which intensify the immune response of the body to the vaccine) since the 1920s. They are the most commonly used, as they have a long record of safety, effectiveness, and low cost – the latter making vaccines affordable. A Cochrane systematic review in 2004 found no difference in the frequency of neurological adverse events in children receiving DTP vaccines containing aluminum adjuvants compared to those vaccinated without.
The FDA allows up to 0.85mg of elemental aluminum (within aluminum compounds) per dose of vaccine (not per vaccination event, though for some reason this is often interpreted as such. I don’t know that this limit has been established). In practice, most vaccines contain less. here is a list of the amounts of aluminum in vaccines given in the US. (From Offit and Jew, 2003). A newer vaccine not listed there, Pentacel (DTaP+IPV+Hib), has 330mcg elemental Aluminum per dose.
The most commonly used adjuvants are aluminum hydroxide crystals and amorphous aluminum phosphate. The vaccine antigens are adsorbed (a sciency word for staying “stuck on” :) ) to the surface of the aluminum compound particles. Once in the body, the antigens are rapidly displaced off the aluminum surface into the interstitial (between the cells) fluid and swept off to the lymphatic system and the bloodstream; what happens to the aluminum compound particles that are left, and where they end up, is what will concern us in Part II of this discussion.