As we prepare for the 2014 influenza season, vaccines are in the news again. Also in the news is the latest chapter in a drawn out drama of vaccine misinformation.
In case you may have missed this, after a long, long saga the Australian Vaccine Information Network (AVN) has finally changed its name to more correctly reflect that it is an anti-vaccination advocacy site.
Now calling themselves the Australian Vaccine-Skeptics Network (and keeping the AVN abbreviation) they are currently sending a series of complaints to the NSW Health Care Complaints Commission in relation to the adverse findings against them.
There are lots of problems with these submissions, but I thought I would highlight just one sentence for you from the most recent complaint.
“Logic suggests that a substance which is inherently neurotoxic is likely to be so at any level.”
No, logic has nothing to do with it. The toxicity of a substance is determined by the laws of chemistry and physics. And part of the laws of chemistry and physics is the understanding that a substance will eventually be too dilute to do harm. As I keep on reminding people “it’s the dose that makes the poison”*. To illustrate, I’m going to give two examples, formaldehyde and Botulinum toxin.
Formaldehyde is a favourite of the anti-vaccine folks; trace levels of formaldehyde are present in some vaccines. Formaldehyde, at moderate concentrations is toxic and extended exposure can cause a variety of adverse health effects, including neurological effects, and formaldehyde has the potential to cause cancer.
Formaldehyde is reasonably reactive; it can bind to and chemically modify proteins. At high enough concentrations formaldehyde can chemically modify enough proteins so that the proteins no longer do their job. This makes it great for inactivating viruses but in humans this process causes toxicity.
But that very reactivity is why our bodies use formaldehyde as part of metabolism. In fact it is required for the synthesis of DNA and some amino acids. Formaldehyde generated from metabolism circulates in our very blood.
So we have a “toxin” that at low levels is part of our normal body makeup (invalidating the AVN statement above). The highest possible doses of formaldehyde a child could get from a vaccine injection would raise their plasma formaldehyde concentration from 2.5 micrograms per millilitre of blood to 2.7 micrograms per millilitre of blood (i.e. no significant effect); providing that the formaldehyde wasn’t immediately scavenged for metabolism or rapidly broken down by the enzyme formaldehyde dehydrogenase.
The levels of formaldehyde in our blood are over 1,000 times less than the levels shown to have damaging effects when taken chronically, so increasing the normal blood levels by 10% (the sort of fluctuation you would see day to day anyway) for less than a day will not do any harm.
The other example is Botulinum toxin. This is the most toxic substance known to humanity to date. A neurotoxin, it is far more toxic than formaldehyde because it is an enzyme. One molecule of formaldehyde reacts with one target molecule and that’s it. As an enzyme, a biological catalyst, Botulinum toxin can potentially react with thousands of target molecules.
And yet we can tame it. Suitably diluted, Botulinum toxin is used to stop involuntary muscle spasm in cerebral palsy, some eye conditions and treat migraine headaches. Some people even inject it into their faces to reduce wrinkles, amongst them people who worry about toxins in vaccines.
You might object that even at these low dilutions, Botulinum toxin is still acting as a neurotoxin, but simple dilution has taken it from being a killer to a localised medicine. Even further dilution will make it completely non-effective.
Toxins are not magic, they do not retain their ability to damage your nervous system through infinite, or even large, dilutions.
That’s a lot of explaining to show how one simple sentence is so badly wrong. The rest of the submissions are just like that. And the sentence they are complaining about is dead wrong too, putting in “ingredients” between “vaccines” and “have not been tested” does not rescue it from wrongness, and the sentence needs to be removed.
If you would like to refresh your memory on why the AVN are wrong on this (particularly their issue with aluminium) and other aspects of “toxins” in vaccines, please visit my post on “toxins” in vaccines. The Australian Academy of Science has lots of good information about vaccines, and if you prefer Respectful Insolence, here’s some details on the lives saved by vaccination.
*Yes, I am well aware of biphasic and non-linear response curves, we pharmacologists discovered them after all, but even with these kinds of responses dilute something enough and the effect goes away.