The Shimmering Cloak
Sunday, February 28, 2010
-Ali bin Abi Talib from Nahgul-Balaghah
It is hard to refute the anti-vaccination movement. It is hard the way shoveling snow is hard, the way running errands on a tight schedule is hard. It hard because work is hard. To thoroughly and completely address anti-vaccinationist rhetoric you must be a polymath, you must pore over numerous journals, look up statistics, be somewhat familiar with the basics of toxicology, chemistry, and biology. On the other hand, in order to generate anti-vaccination rhetoric, you don't need to know anything whatsoever, or prove your statements with facts in any way. It cannot be taken for granted: Attacking a non-facts-based movement with facts alone is not enough.
Arguments with people from the anti-vaccination crowd always run the same way: First the allegation is that thiomersal causes autism. Then it is revealed that thiomersal has been removed from vaccines. Suddenly all kinds of new accusations emerge, that vaccines do not cure disease, or that they cause many other adverse reactions too numerous to list. One can only imagine how the vaccinated must function from day to day- poor delicate things that they apparently are.
Suddenly we find ourselves dealing with a dancing, shimmering cloak, concealing the simple fact that the anti-vaccination movement has no case. We address thiomersal, a shimmer and shift later, and thiomersal is no longer the concern. You can address the basis vaccines have in germ theory, the studies that failed to find a link, the fact that the people who design vaccines believe in vaccination, and generate two mountains of answers for every question raised by the anti-vaccination movement. All of this effort goes to waste. There will always be something else.
For parents trying to make the decision to vaccinate, it can be daunting to see a list of reasons not to vaccinate as long as their arms, but see comparatively little in rebuttal. Rebuttals must be well researched, made carefully, qualified adequately, and are by their nature limited and single-subject. Meanwhile the anti-vaccinationists can cite any number of highly questionable sources. Sources that parents cannot divine the value of for themselves. Scientists and doctors take it for granted that parents can distinguish facts, from fantasy. To a doctor- certain statements can be untrue in obvious and clear ways, but that doesn't mean that a layperson will appreciate the physician's promise that the claimants are "talking moonshine". A knowledgeable person is always hedging, always uncertain. The argument from ignorance is strident and sure.
Take for example: the recent retraction by the Lancet of Andrew Wakefield's paper- which in many respects allowed the anti-vaccination movement to catch fire. This retraction has done little to discourage the proponents of the idea that vaccines are a net harm to society. It has also failed to slake the thirst of many a parent who is out for the blood of the pharmaceutical industry. Of course, a parent who truly believes in the existence of a tangible villain that caused their child's illness can hardly be blamed for falling for the very persuasive narrative put forth by the anti-vaccination community.
So a flash, a glimmer, and a shimmer later we're right back where we started, and claims of censorship abound. This is why I do not feel that the anti-anti-vaccination movement can in fact win a battle of facts and evidence. What brought so many into the folds of the anti-vaccination movement was so much more than evidence and so much less at the same time. Less, in that it will never be sufficient to sway the dispassionate currents of reality as they buffet us about the world. More in that they now believe that every wave carries malice and intent, and they know in their hearts they are being borne off to some deserted island to endure the cruel machinations of some sinister force. Reality is not compelling, it's not a story, and human beings think in stories.
I'm not saying that evidence is unimportant and should never be brought into the discussion. Rather that not every one is appropriately primed to receive it, to incorporate it into the narrative that they have so elaborately woven. We've all seen the courtroom drama. The brilliant young lawyer receives a message pointing to some evidence absolving his innocent client of any guilt. He quickly proceeds to get the case thrown out by interrogating the right witness, or demonstrating conclusively in a single swift Cochranesque bit of elegant logic that his client cannot possibly be the perpetrator. However if we watch enough such dramas, we see there is also a completely different archetype:
Sometimes, there is no further investigation necessary by the inquisitive lawyer, and the evidence is lying in plain sight for all to see. The lawyer's task is not to find new ways of showing the jury the evidence, the reason his or her client is on trial has nothing to do with the evidence. It's the system that put them on trial, and it's the prejudices of the jury that will convict. The task of the usually young, usually spunky, lawyer is in fact much more herculean than a simple cold assembling together of the evidence before the jury: The counselor must instead present his or her case in a way that will shatter the illusions of the jury, obstruct the clear line of sight that they have between their world-view and the matter at hand. Our hero must change their thinking about the case from top to bottom as he destroys the persuasiveness of their precious narrative- so that when they finally move to the quiet of the deliberation room, they finally look to the evidence. In this scenario, the evidence is not the means, but the irrevocable end. The jury must now construct the only narrative that now makes sense, having shed their biases, and the verdict can only be a product of the clues gathered before them.
You cannot do battle with the shimmering cloak. It is, after all- an illusion and an obstruction. Yet every illusion presents an edge to grasp and every act of chicanery has stray thread to be pulled at. We long ago established that we have the answers, it is the questions that must fly fast and furious:
Who payed Andrew Wakefield?
How can an anti-vaccination doctor patent a measles vaccine in good conscience?
What did Jonas Salk charge for his polio vaccine patent?
If it's not thiomersal- what is it?
Why are genetic markers turning up for autism?
How many children die as a result of not vaccinating?
Considering this: On the balance, even if vaccines do cause autism, are the inevitable deaths from infectious disease an acceptable price to pay?
What's in a vaccine?
This last one is asked by our opponents, but only as a hollow point of rhetoric. I think it's a legitimate question, as evidenced by the fact that one anti-vaccinationist I talked to truly believed that vaccines contain animal brain matter. Not only is this untrue, but if it were- we would see the evidence of it in the form of an intense increase of neurological symptoms resembling mad cow disease. Brain matter is a very strange thing to pack into a vaccine anyway. I think that vaccines deserve to be demystified, and the story must be told of how they are made.
Each of the questions above, when answered, raise a set of new and more provocative questions, and each of the answers to those form a brief indelible impression on the person's mind. This series of answers comes at the seeker in a flurry of pictures. The mind, being what is, tries to put the pictures together to tell a story. There, suddenly, a zoetrope unfolds and in that flickering motion our thinker spies a courtroom and a jury that is slowly coming to its senses.
Labels: Thimerosal, Thiomersal, vaccines
When Mercury isn't really Mercury
Sunday, October 25, 2009
Summary
Thiomersal (also known as thimerosal) is a mercury-based preservative used in some vaccines. The level of mercury in vaccines is very low and there is no evidence that thiomersal in vaccines has caused any health problems except minor reactions, such as redness at the injection site. However, because of the potential risk of harm from mercury, thiomersal was removed from most childhood vaccines as a precautionary measure. Follow up studies in children and adults have not shown any harmful effects from thiomersal in vaccines.
The following commonly asked questions are answered in this fact sheet:
What is thiomersal?
Thiomersal, also known as thimerosal, is an organic compound containing 49.6% ethylmercury by weight. It has been used in very small amounts in some vaccines since the 1930s to prevent bacterial and fungal contamination, particularly in multidose vials where withdrawing repeated doses from the same vial was more likely to result in contamination.
In 1999, concerns were raised in the United States that the total amount of mercury, from thiomersal in vaccines given in the infant immunisation schedule, would potentially exceed the recommended level set by a US government agency. There were no studies indicating that the ethylmercury in thiomersal had caused harmful effects in children (except for occasional redness at the injection site); however, it was recommended that thiomersal be removed from many childhood vaccines to eliminate any potential risk. Since that time much more information has been gathered regarding thiomersal ethylmercury).
What is mercury?
Mercury is a metal occurring naturally in the environment. Mercury is found in three main forms: metallic mercury which gives rise to mercury vapour, inorganic mercury (a form in the environment and in animal tissues) and organic mercury (the two main forms of which are methylmercury and ethylmercury). These various forms of mercury are found in the air, earth, aquatic sediment, in fish (particularly in long lived fish such as sharks), and are used in industrial processes, dental fillings, thermometers, and vaccines.
The two organic forms of mercury, methylmercury and ethylmercury (in thiomersal), are closely related but they have important differences. Methylmercury is more potent; it accumulates in the body because the time taken for the body to eliminate it (know as the half life) is about 50 days. Ethylmercury (in thiomersal) does not accumulate in the body to such an extent, because its half life is only about 7-10 days. Ethylmercury is rapidly converted in the body to inorganic mercury, which is excreted in the stool. Mercury can have harmful effects on the central nervous system, skin and kidneys, but most cases of the toxic effects of mercury have been from methylmercury, not ethylmercury.
How much mercury is harmful?
Mercury is harmful only after it reaches a certain level in the body. The toxicity depends on the amount of mercury consumed in relation to body weight, over a period of time. Therefore, because of their size, infants are at greater risk than adults. Different expert bodies have determined that safe levels of mercury consumption lie somewhere between 0.7 µg/kg body weight/week (Environmental Protection Agency, USA) to 3.3 µg/kg of body weight/week (World Health Organization). These values indicate levels of exposure that can be tolerated, and have been deliberately calculated to be much lower than the level at which harm might occur. For example, the EPA level is ten times below the lowest level calculated as causing harm, so there is a large built-in safety margin. In addition, these levels refer to methylmercury, whereas thiomersal is converted to ethylmercury, which is broken down and excreted more rapidly and does not accumulate in the body like methylmercury.
How much mercury exposure results from vaccines?
In Australia, thiomersal has been removed from all routine childhood vaccines since 2000. The exception is one type of Hepatitis B vaccine which contains a greatly reduced amount of thiomersal (see Table 1 below). When thiomersal-containing vaccines were being used before 2000, the maximum number of doses of thiomersal-containing vaccines a 6 month old child might have received was as follows: 3 doses each of diphtheria-tetanus-pertussis vaccine, 3 doses of hepatitis B vaccine, and 3 doses of Hib vaccine. This would have resulted in a total intake of 175 µg of ethylmercury, which is equivalent to about 1.9 µg/kg body weight per week, for an average-sized baby. This level is well below the World Health Organization (WHO) limit for methylmercury discussed above. Two studies measuring mercury levels in the blood in infants given thiomersal-containing vaccines have indicated that their blood concentrations of mercury did not rise above designated levels, except possibly transiently in a premature infant less than 1kg in weight.
In many countries thiomersal continues to be used in vaccines. The Global Advisory Committee on Vaccine Safety (GAVSC) of the WHO has concluded that "there is currently no evidence of mercury toxicity in infants, children or adults exposed to thiomersal-containing vaccines" and that "there is no reason to change current immunisation practices with thiomersal-containing vaccines on the grounds of safety".
What studies have been done to look at the health effects of thiomersal in vaccines?
Many studies in Denmark, Sweden, the United States, and the United Kingdom have now shown that there is no evidence of developmental or neurologic abnormalities resulting from the use of vaccines containing thiomersal. In 2004, a report by the Institutes of Medicine, an independent expert body in the United States, concluded that there is no association between autism and vaccines that contain thiomersal. Also in 2004, an extensive review of all the studies on thiomersal-containing vaccines and autism and neurodevelopmental disorders was published in the journal Pediatrics. Studies looking at autism, mental retardation, speech disorders, and attention deficit disorder, as well as other conditions were reviewed. Overall, the evidence indicated that autism and neurodevelopmental disorders are not associated with thiomersal in vaccines. The reviewers noted that the epidemiologic studies done that suggest a link (notably only by one pair of authors) “have significant design flaws that invalidate their conclusions.”
Why was thiomersal removed from childhood vaccines if there is no danger?
Although there has been a lack of evidence that thiomersal in vaccines is harmful, the recommendations to remove it from vaccines were made for two main reasons. Firstly, it was to reduce exposure in very small premature babies with low body weight in whom there was a theoretical risk that the intake of mercury from repeated doses of thiomersal-containing vaccines could have been high. Secondly, the intent has been to reduce total exposure to mercury in babies and young children in a world where other environmental sources (particularly in food such as fish) may be more difficult to eliminate. Along with these recommendations, guidelines have been developed on limiting the consumption of certain types of fish, particularly in the diet of pregnant women and young children. This advice is available at: http://www.foodstandards.gov.au/whatsinfood/.
In the place of thiomersal, preservatives have either been eliminated from single dose vaccine vials or alternative preservatives have been used. Multidose vaccine vials for are no longer used for routine immunisation in Australia, so the risk of bacterial contamination from withdrawing repeated doses of vaccine is minimal.
What about vaccines for adults?
The levels of mercury in adults resulting from thiomersal-containing vaccines are so low that experts do not recommend removal of thiomersal from vaccines for adolescents or adults. The vaccines available in Australia that currently contain thiomersal are listed below in
Table 2.
Which vaccines contain thiomersal?
All vaccines on the current Australian Standard Vaccination Schedule (ASVS) for infants and children under the age of 8 years are now free of thiomersal. The exception is the one of the infant hepatitis B vaccines, Engerix-B paediatric formulation, which contains a greatly reduced amount of thiomersal (2 µg per dose). The following tables list the vaccines used in Australia that are thiomersal free and vaccines that contain thiomersal.
Table 1:
Thiomersal-free vaccines available for use in infants and children in Australia
| Vaccine | Trade Name | Manufacturer |
|---|---|---|
| Hepatitis B | H-B-VaxII* preservative-free paediatric formulation | CSL/Merck Sharpe & Dohme |
| DTPa | Infanrix and Tripacel | GlaxoSmithKline, CSL |
| DTPa-hepatitis B | Infanrix-Hep B | GlaxoSmithKline |
| DTPa-IPV | Infanrix-IPV | GlaxoSmithKline |
| DTPa-hepatitis B-IPV | Infanrix-Penta | GlaxoSmithKline |
| DTPa-hepatitis B-IPV-Hib B PRPT | Infanrix-Hexa | GlaxoSmithKline |
| Hepatitis B - Hib B PRP-OMP | Comvax | CSL |
| Haemophilus influenzae B OMP | Liquid PedVaxHIB | Merck Sharpe & Dohme |
| Haemophilus influenzae B PRPT | ActHib | Pasteur Mrieux |
| Haemophilus influenzae B HbOC | HibTITER | Lederle |
| Measles, mumps, rubella | MMR II, Priorix | CSL, GlaxoSmithKline |
| Meningococcal group C conjugate vaccines | Meningitec, Menjugate, NeisVac-C | Wyeth, CSL, Baxter |
| Oral polio vaccine | OPV | CSL |
| Inactivated polio vaccine (IPV) | IPOL | Aventis Pasteur |
| Polysaccharide pueumococcal vaccine | Pneumovax 23 | Merck Sharpe & Dohme |
| 7-valent pneumococcal conjugate vaccine | Prevenar | Lederle |
| Varicella vaccine | Varilrix | GlaxoSmithKline |
| Varicella vaccine | Varivax | CSL/Merck Sharpe & Dohme |
| Influenza vaccine | Vaxigrip, Fluvax | Aventis Pasteur, CSL |
Table 2:
Vaccines available in Australia that contain thiomersal
| Vaccine | Trade Name | Manufacturer | Dose of thiomersal |
|---|---|---|---|
| Combined diphtheria and tetanus vaccine | CDT | CSL | 50 micrograms |
| Adult diphtheria and tetanus vaccine | ADT | CSL | 50 micrograms |
| Diphtheria vaccine | CSL | 50 micrograms | |
| Hepatitis B | Engerix B Adult | GlaxoSmithKline | <2 micrograms |
| *Influenza vaccines | Fluarix, Influvac, Fluvax | GlaxoSmithKline, Solvay, CSL | 50 micrograms |
| Japaneseencephalitis vaccine | JE Vax | CSL | 35 micrograms |
| Q fever vaccine | Q vax | CSL | 50 micrograms |
*Thiomersal-free influenza vaccines are listed in Table 1.
1. Mercury and vaccines (Thimerosal). Centers for Disease Control. Link (accessed November 23, 2004).
2. American Academy of Family Physicians (AAFP), American Academy of Pediatrics (AAP), Advisory Committee on Immunization Practices (ACIP), United States Public Health Service (PHS). Joint Statement concerning removal of thimerosal from vaccines. Link (accessed November 23, 2004).
3. Centers for Disease Control. Mercury and vaccines Fact Sheet. Link (accessed November 23, 2004).
4. Recommendations regarding the use of vaccines that contain thimerosal as a preservative. Morbidity and Mortality Weekly Report 1999. Link (accessed November 23, 2004).
5. Institute of Medicine Immunization Safety Review Committee, Stratton K, Gable A, McCormick MC, editors. 2001. Thimerosal-containing vaccines and neurodevelopmental disorders. Link (accessed November 23, 2004).
6. Institute of Medicine Immunization Safety Review Committee. Vaccines and Autism. Washington, DC: National Academy Press, 2004, in press Prepublication review available at: http://books.nap.edu/catalog/10997.html (accessed November 23, 2004).
7. Institute of Medicine Press Release. MMR Vaccine and Thimerosal-Containing Vaccines Are Not Associated With Autism. May 18, 2004. Link (accessed November 23, 2004).
8. European Agency for the Evaluation of Medicinal Products (EMEA). Statement on thiomersal in vaccines. Link (accessed November 23, 2004).
9. Thiomersal and vaccines:questions and answers. World Health Organisation. Scientific papers. Link (accessed November 23, 2004).
10. Parker SK, Schwartz B, Todd J and Pickering LK. Thimerosal-Containing Vaccines and Autism Spectrum Disorder: A Critical Review of Published Original Data. Pediatrics 2004; 114(3): 793-804
11. Heron J, Golding J, and ALSPAC Study Team. Thimerosal Exposure in Infants and Developmental Disorders: A Prospective Cohort Study in the United Kingdom Does Not Support a Causal Association. Pediatrics 2004; 114(3): 577-583.
12. Study Fails to Show a Connection Between Thimerosal and Autism. Source: American Academy of Pediatrics, May 16, 2003. Link (accessed November 23, 2004).
13. Clements CJ. The evidence for the safety of thiomersal in newborn and infant vaccines.Vaccine. 2004 May 7; 22(15-16): 1854-61.
14. Offit, P.A. and Jew R.K. Addressing Parents' Concerns: Do Vaccines Contain Harmful Preservatives, Adjuvants, Additives, or Residuals? Pediatrics. 2003 112(6): 1854-1861.
15. Madsen KM, Lauritsen MB, Pedersen CB, et al. Thimerosal and the occurrence of autism: negative ecological evidence from Danish population-based data. Pediatrics 2003; 112: 604-606.
16. Verstraeten T, Davis RL, DeStefano F, Lieu TA, Rhodes PH, Black SB, Shinefield H, and Chen RT. Safety of Thimerosal-Containing Vaccines: A Two-Phased Study of Computerized Health Maintenance Organization Databases. Pediatrics 2003; 112(5): 1039-48.
17. Stehr-Green P, Tull P, Stellfeld M, Mortenson PB, and Simpson D. Autism and thimerosal-containing vaccines: Lack of consistent evidence for an association. American Journal of Preventive Medicine 2003; 25(2): 101-6.
18. Nelson, KB, and Bauman, M.L. Thiomersal and autism? Pediatrics 2003; 111: 674-679.
19. Henderson DC. Mercury in vaccines - reassuring news. Lancet 2002 (Nov 30); 360: 1711-12.
20. Pichichero ME, Cernichiari E, Lopreiato J, Treanor J. Mercury concentrations and metabolism in infants receiving vaccines containing thiomersal: a descriptive study. Lancet 2002 (Nov 30); 360: 1737-41.
21. Clements CJ, Ball LK, Ball R, Pratt D. Thiomersal in vaccines. Lancet 2000; 355: 1279-1280.
22. Halsey NA. Limiting infant exposure to thimerosal in vaccines and other sources of mercury [editorial]. Journal of the American Medical Association 1999; 282: 1763-6.
Online resources
* "Sticking Up for Thimerosal: Read the studies — it's safe." To access "Sticking Up for Thimerosal," go to: http://slate.msn.com/id/2123647
* Information about mercury and vaccines can be found at: http://www.cdc.gov/nip/vacsafe/concerns/thimerosal/default.htm#facts
* Information about autism can be found at: http://www.cdc.gov/ncbddd/dd/aic/about/default.htm
* Synopses of articles from the scientific, peer-reviewed literature related to vaccines and immunization can be found at: http://www.immunizationinfo.org/immunization_science.cfm?cat=1
* Thimerosal-related resources for parents/patients can be found at: http://www.vaccineinformation.org/thimerosal.asp
* Journal abstracts related to thimerosal can be found at: http://www.immunize.org/safety/thimerosal.htm#journalarticles
* A transcript from the HHS Media Briefing on Vaccines and Child Health (held July 19, 2005) is at: http://www.cdc.gov/od/oc/media/transcripts/t050719.htm
* FREE DOWNLOAD OF IOM REPORT:
The IOM report "Immunization Safety Review: Vaccines and Autism", released May 2004, is now available to download free as a ready-to-print (PDF) document. To access it, go to: http://www.nap.edu/catalog/10997.html (Click on "sign in to download", and follow the instructions).
This document was prepared by the National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases. Updated November, 2004.
This document was written by Associate Professor Raina MacIntyre, Professor Margaret Burgess, Associate Professor Peter McIntyre and Dr Kristine Macartney of the National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases.
[Note: This is a repost of last Monday's article, of the same title, because my colleague, Larian LeQuella, made a SNAFU of doing a "copy & paste" job of the HTML tables in the original post; not really his fault, the web-master/developer at the other website, from which the original article was sourced, did not configure the HTML tags for the tables correctly — probably was goofing off at work! — and, consequently, the system here misinterpreted them — which I had to completely debug! Also, this blog works best with CSS rather than HTML tags.]
Labels: Thimerosal, Thiomersal, vaccines
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