Mercury in vaccines as a cause of autism and autism spectrum disorders (ASDs): A failed hypothesis

Blogging on Peer-Reviewed ResearchOne of the most pernicious medical myths of recent years has been the claim, promulgated by a subgroup of parents of autistic children and facilitated by scientists of dubious repute, that somehow the mercury in the thimerosal (ethyl mercury) preservative used in common childhood vaccines in the U.S. until early 2002 causes autism. Although it had been percolating under the radar of most parents and scientists for several years before, this belief invaded the national zeitgeist in a big way in 2005, beginning with the publication of a book by journalist David Kirby entitled Evidence of Harm: Mercury in Vaccines and the Autism Epidemic: A Medical Controversy. The fires of hysteria were stoked even higher by Robert F. Kennedy, Jr., who published a truly twisted and misleading piece of pseudojournalism and pseudoscience published simultaneously in Rolling Stone and on entitled Deadly Immunity. Relying primarily on quote-mining of the transcripts of both a conference held Atlanta by the CDC to discuss the question of whether autism is related to thimerosal in vaccines and an Institute of Medicine report on vaccines while simultaneously misrepresenting the results of two studies by Verstaeten et al to paint a false picture of a government coverup, RFK Jr. almost single-handedly managed to stoke fears that vaccines were causing an “epidemic of autism.”

I say “almost” single-handedly, because, unfortunately, he had help. Relying on the dubious research of a variety of investigators, such as the father-and-son team of Dr. Mark Geier and David Geier, whose prodigious output of badly designed studies emanating from a lab in their home in suburban Maryland, done using a rubberstamp institutional review board stacked with friends and cronies to approve the studies, and published for the most part in non-peer-reviewed journals, activists loudly insisted that mercury in vaccines was the cause of most autism. Others claiming to demonstrate this link include Boyd Haley, a chemist from the University of Kentucky, and a few other vocal scientists and advocates, who claim that autism is, in essence, mercury poisoning. Facilitating the dissemination of this message were reporters such as David Kirby, activists such as Robert F. Kennedy, Jr., and media personalities such as Don Imus. Indeed, some activists claimed that some vaccines were “poisoning” our children, even going so far as show photos of autistic children with the label “mercury-poisoned” underneath them on placards held aloft at protest rallies. They made quite a splash then, and still do to a lesser extent even today. There’s just one problem.

The scientific data, taken in totality, do not support a link between mercury in vaccines and autism. Today yet another important study by Robert Schechter and Judith Grether was released published in the Archives of General Psychiatry entitled Continuing Increases in Autism Reported to California’s Developmental Services System: Mercury in Retrograde1, that utterly failed to support the hypothesis that mercury in vaccines is an etiological factor in autism. It is yet another nail in the coffin of the medical myth that mercury in vaccines causes autism.

Before I discuss this new study in more detail, a bit of background is in order. In response to the FDA Modernization Act of 1997, prior to the hypothesis that thimerosal might cause autism the US Food and Drug Administration (FDA) compiled a list of vaccines and how much thimerosal they contained. Thimerosal had been commonly used to prevent microbial contamination of vaccines, particularly multidose vials, since the 1930s. It could be reasonably argued that, given the more lax standards of the time, thimerosal had not been adequately tested before use in humans, but decades of use after that had, as far as could be discerned, revealed only occasional skin hypersensitivity reactions due to this component. By 1999, under the recommended schedule of childhood vaccines at the time, concern was expressed that infants, before six months of age, were potentially being exposed to cumulative doses of ethyl mercury that may have exceeded safety standards. It should be noted that these safety standards were based on an indirect surrogate of ethyl mercury, namely methyl mercury, and largely in the absence of any real data. In July 1999, the American Academy of Pediatrics and the U.S. Public Health Service decided, as a precaution, to recommend that thimerosal be removed as soon as possible from childhood vaccines.

It did not take long for this recommendation to be implemented. By March 2001, all vaccines in the recommended infant vaccination schedule were available in forms that had at most traces of thimerosal left over from the manufacturing process. The last lots of childhood vaccines with thimerosal had expiration dates in 2002. Indeed, as Arthur Allen documented in his recent book Vaccine: The Controversial Story of Medicine’s Greatest Lifesaver, a survey of several hundred medical offices in February 2002 conducted by the CDC found that, of the three pediatric vaccines that contained thimerosal in the 1990s, only 2% of vaccine stock still contained thimerosal. Since then, with the exception of the flu vaccine, no childhood vaccine in the U.S. has contained more than trace amounts of thimerosal. There has been considerable debate over whether the decision to remove thimerosal was undertaken too quickly. True, at the time it seemed like a prudent, cautious step. However, the decision had unintended consequences. One was that it resulted in a temporary shortage of childhood vaccines. More importantly, though, it fed the fears of activists that the mercury in vaccines must really be harmful. After all, if it weren’t harmful, why would the AAP and PHS recommend its removal?

Why indeed? The use of this precautionary measure, which to health officials seemed prudent at that time, as justification for attacking the safety of vaccines is as good an example of how no good deed goes unpunished as I’ve ever seen. Many parents, faced with the enormous challenge of raising autistic children, not unreasonably wondered whether there was something wrong with vaccines in the first place.

The second bit of background information that you need to know is that, over the last couple of decades, the incidence of autism and autism spectrum disorder (ASD) has increased markedly to an estimated 1 in 150 children. Robert F. Kennedy, Jr. and others who believe that mercury in vaccines somehow cause autism have referred to this increase as an “autism epidemic” (or, more offensively, as an “autism tsunami“) and frequently claim that there must be an environmental factor that has led to this increase. Because the symptoms of autism, such as cognitive delay and withdrawal from interaction with parents, often manifest themselves between one and three years of age and because this is the age when children receive the bulk of their vaccines, there is a correlation. However, correlation does not necessarily equal causation. It may, but often it does not. Often the correlation is spurious, unrelated, or related to a common factor. More investigation is always required to determine if an apparent correlation is or is not due to causation. In the case of autism, there is good evidence, most recently published by Paul Shattuck2, that increased awareness and diagnostic substitution since the criteria for a diagnosis of ASD were broadened in 1994 account for the apparent increase in diagnoses of autism, as pointed out by Arthur Allen and Roy Grinker.

Regarding the question of vaccines and autism, for ethical reasons we cannot do a double-blind, randomized, control trial of vaccines with and without thimerosal. However, we can do the next best thing, and, indeed, we now have several good studies since 1999 that do just that. Some of these studies are epidemiological; some are ecological. What allows us to use them to reject the hypothesis that mercury in vaccines is an etiological agent that is either associated with or causes autism is a very simple but powerful prediction that the hypothesis makes. Quite simply, if the hypothesis is true and thimerosal-containing vaccines (TCVs) cause autism (or are even merely a significant contributing factor), we would expect that the removal of thimerosal from vaccines would lead to a rapid decrease in autism incidence and prevalence within 2-5 years.

There have now been several studies that examined this very hypothesis in countries that removed thimerosal from their vaccines before the U.S. did. For example Hviid et al3 reported that autism prevalence in Denmark increased from 1991 to 1996 despite the removal of thimerosal from vaccines, while Madsen et al4 looked at the time period from 1971 to 2000 and concluded that autism diagnoses continued to increase after thimerosal was removed from vaccines. Neither study supported a causal link between TCVs and autism, and they were a prominent part of the dataset that was used by the Institute of Medicine to conclude in 2004 that there was no good evidence to support a link between TCVs and autism. A more recent study by Eric Fombonne5 in Montreal examined 27,749 children born from 1987 to 1998 attending 55 different schools. Cumulative thimerosal exposure by age 2 years was calculated for the 1987-1998 birth cohorts. This exposure ranged from 100-125 μg from 1987 to 1991, 200-225 μg from 1992 to 1995, and then none after 1996, which was when thimerosal was completely removed from vaccines in Canada. The result was that autism, ASD, and pervasive developmental disorder diagnoses continued to increase in all periods, demonstrating no relationship between TCVs and autism or ASDs. Even more recently, a large study6 failed to support a relationship between thimerosal and adverse neurodevelopmental outcomes, a result that led one of the investigators in the study, Sallie Bernard, a proponent of the thimerosal hypothesis, to disavow the study in a case of sour grapes, because it did not show what she had hoped that it would show.

We are now nearly six years out from the near-complete removal of thimerosal from vaccines. Other than the flu vaccine, there is no more than trace thimerosal in any childhood vaccine; overall mercury exposure due to vaccines has not been this low in decades. Consequently this hypothesis can now be tested in the United States. In a deliciously ironic twist, Schechter and Grether1 chose to use a source of data that has frequently been widely abused by advocates claiming a link between TCVs and autism to try to show one where there isn’t one as though the conclusions were foreordained. Although it is probably not, it has even been referred to as the “gold standard” of autism epidemiology by none other than David Kirby. Indeed, this is the very same database in which David Kirby predicted that there should be a noticeable decrease in new diagnoses of autism by 2007 if the thimerosal hypothesis is true and then later shifted the goalposts to 2011 when it became apparent that there has been no decrease. This source is the California Department of Developmental Services (CDDS) database. The CDDS administers a statewide system of regional centers and developmental centers designed to serve people who are substantially disabled because of autism, mental retardation, or other developmental disabilities. It maintains an archive file of client developmental evaluation reports on clients enrolled in the system. Among the strengths of the system are that it is a population-based system representing the most populous state in the U.S. Moreover, the client reporting form was consistent throughout the study period, preventing confounders due to changes in reporting. The weaknesses of the CDDS is that its data is derived from an administrative system that was designed to track enrollment and fiscal data and is not as well suited to measuring the occurrence of developmental disabilities in the population. However, with proper statistical analysis, considerable information can still be gleaned from this data for specific birth cohorts.

In order to ask the question of whether autism rates had declined, Schechter and Grether examined data for clients with active status reported from January 1, 1995 to March 31, 2007. Using careful statistical analyses, they used two approaches to measure the occurrence of ASD during this period. The second approach, in which ASD prevalence was determined in the 3 to 5 year old cohort, is perhaps the most informative. It shows a continuing increase in autism prevalence without even a blip or decrease in the rate of increase after 2002. Indeed, showing the skill of some bloggers to analyze the same data, the money figure in the paper (Figure 3) looks almost exactly the same as the graph prepared in early 2007, a continually increasing curve since 1995. This result is not only consistent with multiple other published and unpublished studies, including the aforementioned Danish and Canadian studies7, but it is about as unambiguous evidence as can be obtained from a database like the CDDS database. Indeed, despite the limitations of the use of this database, it is an excellent example of proponents of a “mercury injury” hypothesis of autism being “hoisted by their own petard,” so to speak. Indeed, Eric Fombonne, in a blistering editorial8 that accompanies this study, agrees:

The particular significance of the study by Schechter and Grether is that it relies on the California Department of Developmental Services database, which has been systematically used by proponents of the thimerosal hypothesis to argue that the rising number of children accessing these services— or the “epidemic” of autism— was linked to the increasing exposure to ethylmercury of US children occurring in the 1990s through the changes in the immunization schedule. To the contrary, the data analyzed by Schechter and Grether9 provide a clear and unambiguous test that shows that the expected decline in autism rates following discontinuation of thimerosal in US vaccines did not occur.

Noting that, “with the exception of studies conducted by a single pair of authors” (with uncharacteristic restraint Fombonne does not name whom he obviously meant, namely Mark and David Geier), all studies done have thus far failed to find a link between TCVs and autism, Fombonne continues:

Despite the accumulation of scientific evidence rejecting these 2 hypotheses linking autism to various components of childhood vaccines, these theories and the practices that accompany them have not faded away. Why? How many more negative study results are required for the belief to go away, and how much more spending of public funds on this issue could even be justified?

He then postulates an explanation that I happen to agree with:

Outside academic circles, powerful advocacy groups developed and started to lobby decision makers to influence decisions about which autism research to fund and even how to conduct it. Unaware of scientific studies, or worse, doubtful of their results, bestselling writers, journalists, and politicians were drawn to embrace conspiracy theories that portrayed vaccine manufacturers and the Centers for Disease Control and Prevention as public enemies.15 Law firms saw an opportunity to obtain large financial compensations from the US Vaccine Injury Compensation Court or before local federal courts, the viscous US legal process allowing for fermentation of misconceptions. Exploiting further families’ beliefs and their understandable desire to try everything possible to help their children, charlatans developed alternative (and lucrative) “treatments” for autism, which included chelation therapy, use of a hyperbaric oxygen chamber, and testosterone suppression. All are of unproven efficacy, and many are dangerous.

In other words, it’s all about obtaining compensation for nonexistent “vaccine injury” and “biomedical treatments” for this injury. Never mind that these “treatments” are neither scientifically plausible nor have convincing evidence in the form of well-designed clinical trials to support their efficacy in ameliorating the cognitive delays observed in autistic children. Unfortunately, parents who love their autistic children and desperately want to do something to “make them better” are fertile ground for the blandishments of proponents of these implausible and unproven “therapies.” Some of these treatments, such as chelation therapy, which, it is claimed, will remove the mercury that, according to proponents of the thimerosal hypothesis, is the root cause of autism, have developed into veritable cottage industries that prey on desperate parents. It has even progressed to the point where the Geiers can convince some parents that most autistic children exhibit signs of “precocious puberty” and that the elevated testosterone in such children forms “sheets” that bind mercury and prevent it from being chelated properly. As hard as it is to believe, they then use that claim as a justification for using powerful anti-androgenic drugs such as Lupron on autistic children to treat their autism.

Vaccination is arguably the most effective single public health intervention ever developed. As recently as 50 years ago, for example, our parents and grandparents lived in deathly fear of diseases like polio, which is virtually a thing of the past. Because they are preventative in nature and administered to a very large population of healthy people, vaccines have a very high hurdle to jump as far as safety is concerned, because when an intervention is performed on millions of otherwise healthy people, even a low rate of complications can result in large numbers of injured people. Modern vaccines have achieved that level of safety. Are they completely safe? Nothing in medicine is absolutely, 100% safe. In comparison to the risk of the diseases they prevent and by any reasonable standard, the risks due modern vaccines are extremely low. Moreover, the claims of proponents of an increasingly untenable hypothesis to the contrary, there is no convincing evidence that thimerosal-containing vaccines, or vaccines in general, have anything to do with the etiology of autism. Whatever tiny risk there may be from childhood vaccines, autism and ASDs are not among them. Indeed, even before this study by Schechter and Grether, under the onslaught of studies that all fail to find a link between thimerosal and autism, even David Kirby and those more zealous than him were starting to back away from the hypothesis, invoking hand-waving and vague “environmental toxins” or even going so far as to blame mercury from pollution wafting over from China or, even more ludicrously, mercury from the cremation of bodies with mercury amalgam dental fillings. Meanwhile, in the wake of this study, Mark Blaxill is retreating to saying that “the epidemiological analysis doesn’t prove that thimerosal exposure cannot cause individual cases of autism” and blaming vaccines in general for autism (while also not being able to wait for the embargo to try to put his spin on the matter, by the way).

This study is clearly but one more nail in the coffin of this dying hypothesis. Unfortunately, like Jason in the Friday the 13th movies, the hypothesis that mercury in vaccines is a major cause of autism just refuses to die, no matter how many studies fail to find even a wisp of a link between the two. Just when you think it’s finally, really dead, it has an unpleasant way of being resurrected. That’s why it is not difficult to predict that the usual suspects will refuse to believe it, just as they have refused to believe the studies preceding it.


  1. Schechter R and JK Grether (2008). Continuing Increases in Autism Reported to California’s Developmental Services System. Arch. Gen. Psychiatry 65: 19-24.
  2. Shattuck P (2006). The Contribution of Diagnostic Substitution to the Growing Administrative Prevalence of Autism in US Special Education. Pediatrics 117:1028-1037.
  3. Hviid A, M Stellfeld, J. Wohlfahrt, and M Melbye (2003). Association between thimerosal-containing vaccines and autism. JAMA 290:1763-1766.
  4. Madsen KM, MB Lauritsen, CB Pedersen, P Thorsen, AM Plesner, PH Andersen, PB Mortensen (2003). Thimerosal and the Occurrence of Autism: Negative Ecological Evidence From Danish Population-Based Data. Pediatrics 112:604-6.
  5. Fombonne E, R Zakarian, A Bennett, L Meng, D. McLean-Heywood (2006). Pervasive Developmental Disorders in Montreal, Quebec, Canada: Prevalence and Links With Immunizations. Pediatrics 118:e139-50.
  6. Thompson WW, C Price, B Goodson, DK Shay, P Benson, VL Hinrichsen, E Lewis, E Eriksen, P Ray, SM Marcy, J Dunn, LA Jackson, TA Lieu, S Black, G Stewart, ES Weintraub, RL Davis, F DeStefano; Vaccine Safety Datalink Team (2007). Early Thimerosal Exposure and Neuropsychological Outcomes at 7 to 10 Years. NEJM 357:1281-1292.
  7. Parker SK, B Schwartz, J Todd, and LKPickering (2004). Thimerosal-containing vaccines and autistic spectrum disorder: a critical review of published original data. Pediatrics 114:793-804.
  8. Fombonne E (2008). Thimerosal disappears but autism remains. Arch. Gen. Psychiatry 65: 15-6.

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55 thoughts on “Mercury in vaccines as a cause of autism and autism spectrum disorders (ASDs): A failed hypothesis

  1. Beauzeaux says:

    I was born in 1942 so I remember what life was like before the polio vaccine. Parents were terrified. Every summer there were waves of polio cases. Kids died. Or worse, they were condemned to iron lungs “for life.”
    Swimming pools were closed. Picnics were cancelled. No one knew what caused it or how to avoid it.
    I lived less than half a mile from the famous Sister Kenny Hospital where the severest cases went. It was a busy place.
    Then the Salk and then Sabin vaccine arrived and in a matter of a few years, Sister Kenny’s hospital had no patients amd it closed.
    I just wish these anti-vaccination idiots could visit 1950 for a month. Or maybe they could drop in on hospitals in the 1920s when there were 100,000 to 200,000 cases of diphtheria every year in the United States, causing 13,000 to 15,000 deaths, most of them children.
    Or maybe they could witness a case of tetanus.

    I am infuriated by these smug ignoramuses who are clearly willing to let these horrible diseases stalk their own children, and by extension, everyone. What do they thibnk will happen if we all stop getting vaccinations?? We’ll be able to stave off yellow fever and tetanus with a homeopathic pill?
    A resurgence of these plagues will be on their heads! (Not that it will be any comfort to the rest of us.)


  2. Hey Zeus is my Homeboy says:

    As shocking as the ignorance is regarding the antivaccination extremists, Mark Blaxill’s unprofessional, egotistical, and ignorant rant is beyond the pale. He has truly lowered himself to new depths with this one.

    But for those who follow his career in dibble-dabble science, this kind of reaction to reason is expected. Mark Blaxill has no place in the science of autism and it now appears that he doesn’t even pretend to want to be taken seriously.

    Gee, I wonder why he lost his job?

  3. Kev says:

    “Indeed, this is the very same database in which David Kirby predicted that there should be a noticeable decrease in new diagnoses of autism by 2007 if the thimerosal hypothesis is true and then later shifted the goalposts to 2011 when it became apparent that there has been no decrease. “

    Quite right, but its even better than that. In an interview in 2005, Kirby said the same thing (See third movie from bottom). That now makes three times Kirby has moved his goalposts when his expectations aren’t met.

  4. diggs says:

    I’d like to point out that both Salk and Sabin said that the polio vaccine had nothing to do with the disappearance of the disease, it had simply run it’s course like all epidemics do. Further, the junk science supporting vaccines is supported by fear based propaganda with very little real evidence indicated. If vaccines work so well, why does anyone care if a few people don’t get them? What threat is it to those of you who do? Won’t you be protected from the diseases? I love when people say that those who don’t get vaccinated are a threat to those who do, it proves that people don’t really believe in the vaccines. Has everyone in the medical community forgotten that we have immune systems and the reason that so many of us have weakened immune systems is because we keep plunging our bodies into vats of chemicals? Thimerisol is not the only problem with vaccines; the spread of other diseases through them, the vast amounts of other chemicals, the fact that the diseases in them don’t pass through our immune system in any way that it recognizes, the list goes on and on ending with they simply don’t work. These aren’t rogue scientists saying it, they are from Harvard, Merck, U of C and many other esteemed places. Today we have better nutrition, clean water, sanitary conditions and if you think those things don’t make a difference you are completely mistaken and need to expand your research.

  5. DaveCarlson says:

    diggs – I very much doubt that argumentum ad assertion is going to fly in this house. Nice try, though.

  6. HCN says:

    Actually, diggs, the clean water and sanitary conditions made it so that polio attacked when children were older. Babies usually had lesser symptoms, but older folks suffered more.

    Here is an explanation that you should understand:

    Also, how does the sanitary condition explanation work for Japan? In the early 1990s they made the measles vaccine voluntary. Then during the next few years the cases of measles increased to the point that several college campuses were closed to stop the spread of measles.

    Did Japan have a sudden change in sanitary conditions? Or was there a change in vaccine coverage? What is the most logical explanation for the levels of measles to go from a low of less than 900 to over 30000:

  7. PalMD says:

    I’d like to point out that both Salk and Sabin said that the polio vaccine had nothing to do with the disappearance of the disease, it had simply run it’s course like all epidemics do.
    Be prepared to back up that assertion about S and S. Also, all epidemics to not necessarily “run out of steam”.

    Further, the junk science supporting vaccines is supported by fear based propaganda with very little real evidence indicated. If vaccines work so well, why does anyone care if a few people don’t get them? What threat is it to those of you who do? Won’t you be protected from the diseases?

    Junk science? Prove assertion please. Answers: 1) herd immunity, 2, etc) e.g. my pertussis immunity is prob not so good anymore and i don’t want some idiot giving it to me (or my child, who may not be immune yet)

    I love when people say that those who don’t get vaccinated are a threat to those who do, it proves that people don’t really believe in the vaccines. Has everyone in the medical community forgotten that we have immune systems and the reason that so many of us have weakened immune systems is because we keep plunging our bodies into vats of chemicals?
    Too many unfounded assertions, im getting dizzy.

    Thimerisol is not the only problem with vaccines; the spread of other diseases through them, the vast amounts of other chemicals, the fact that the diseases in them don’t pass through our immune system in any way that it recognizes, the list goes on and on ending with they simply don’t work. These aren’t rogue scientists saying it, they are from Harvard, Merck, U of C and many other esteemed places. Today we have better nutrition, clean water, sanitary conditions and if you think those things don’t make a difference you are completely mistaken and need to expand your research

    Arghh! Have you ever taken a biology class???!!1111!!

  8. Harriet Hall says:


    I wasn’t aware that Salk and Sabin said that. Do you have original sources?

    Improved sanitation is extremely important, but it is not enough by itself. Without the polio vaccines, the incidence of the disease in the US might have waned naturally but there eventually would have been more outbreaks. With the vaccine, it has entirely disappeared from the US. There are many examples of two countries with similar sanitation standards where the incidence of a disease was lower in the country that vaccinated. I know of no instance where sanitation alone eradicated the diseases we vaccinate for.

    Vaccines work well, but they don’t provide 100% immunity, and immunity can wane over time. Because of this, even vaccinated populations are still somewhat vulnerable to disease. My niece was immunized against whooping cough, but she caught it as a teenager; this could not have happened if the herd immunity was sufficient to keep it out of the community.

    Polio had been eradicated from all but 3 countries, and when Nigeria let the rate of immunization lapse, an epidemic occurred that spread to several other countries. This kind of thing has been observed over and over: in Japan, Great Britain, the US, and other countries, for whooping cough, polio, and other diseases. When the immunization rate drops, the rate of disease increases; when the immunization rate rises again, the rate of disease decreases again. How many times do we have to be taught this same lesson?

    Is it true that we have weakened immune systems? Weakened compared to what? What is your evidence?

    I don’t understand at all what you are talking about with “the diseases in them don’t pass through our immune system in any way that it recognizes.” I thought the same blood test was used to detect immunity from natural disease and from vaccines. Am I wrong?

    I don’t think I am exposed to “vast amounts” of chemicals, and I certainly haven’t plunged my body into any vats of chemicals recently. :-)

  9. TheProbe says:

    diggs said: I’d like to point out that both Salk and Sabin said that the polio vaccine had nothing to do with the disappearance of the disease, it had simply run it’s course like all epidemics do.

    diggs, let me suggest that you make an effort to find out where they said that. A recent discussion in one of the Usenet groups pointed out that the origin of the quotes could not be found. Furthermore, the only websites using the quotes were the usual anti-vaccination liar sites.

    The person proposing the quotes as valid eventually left the group, never being able to validate them. ‘

    It is a typical ploy of anti-scientists and their sycophants to use quotes of dead people, since there is not way to conclusively prove that the dead perrson did not say it.

  10. David Gorski says:

    I have to echo Harriet and TheProbe in asking digg to reference his/her source for the claim that Sabin and Salk both said that the polio vaccine didn’t have anything to do with the disappearance of the disease. It’s a quote that shows up on antivaccination websites a lot but for which I’ve never been able to track down an original source that isn’t an antivaccination website or an antivaccinationist like digg posting to Usenet or blog comments.

    Harriet also beat me to the punch in her comments regarding the claim that better sanitation is what eliminated polio–another favorite antivaccinationist canard. I only wish to add that it’s a straw man argument that I ever claimed that better sanitation and nutrition don’t make a difference. However, vaccines make a bigger difference. Another example is in the UK, where, in response to Andrew Wakefield’s dubious “study,” fearmongering about the MMR vaccine led to a marked decline in vaccination rates. (In the U.S. antivaccinationists blame mercury for autism; in the UK, they seem to prefer the MMR as a bogeyman.) The completely predictable result was that measles returned in a big way.

  11. Joe says:

    According to “Viruses” by Arnold J. Levine (Scientific American Library, 1992, pp. 61-4) sanitation led, paradoxically, to burgeoning rates of polio in the first half of the last century. He says that newborns in less sanitary environments were exposed to the virus, and it was attenuated by antibodies in breast milk while the babies developed their own immunity. After the development of sanitation, suckling babies were not exposed to the virus. When they ventured out on their own, they lacked their natural immunity.

    If Professor Levine is correct, sanitation spread polio as opposed to wiping it out, before vaccination.

  12. mike stanton says:

    As a UK citizen I can confirm that improved sanitation levels have not prevented the re-emergence of measles and mumps as vaccine rates declined in this country.

  13. PalMD says:

    In Evanston, IL, the Rotary Club HQ building has a publicly displayed statue of Jonas Salk surrounded by children. It’s one of the more poignant statues I’ve ever seen—I walked by it every day on my way to the train to the hospital, and found it inspiring. I don’t think there are any rational people in the world who can deny the contribution of Sabin and Salk and vaccines.
    I would think that if they had made the comments diggs attributes to them, perhaps the statue, and most textbooks would reflect this…Oh, wait, I forgot about the vast conspiracy thingy.

  14. daedalus2u says:

    As a researcher working on the connections between ASDs and nitric oxide physiology, what really drove the stake through the dead horse that is the “mercury causes autism” idea (to mix a few metaphors) is the Holmes paper on first haircut baby hair. One of the normal controls had 100 times the mercury that the most severely affected children had. There is simply no physiologically plausible (or even possible) mechanism for anyone to have toxic blood levels of mercury with those hair levels.

    The correlation between hair and blood mercury would have to be skewed by 3 or 4 orders of magnitude for that to happen. Such a skewing has never been observed in any organism ever. Everything that is well known about mercury physiology would say it is not possible.

    There has been a study of the incidence of autism in the Faroe Islands (Ellefsen A, 2007) that includes the 1,000+ child cohort that was tested for mercury at birth via cord blood, maternal blood and hair and via umbilical cord (all of which cross correlated very well, with no outliers) (Grandjean P, 2005). 750 of those children had cord blood mercury levels above 65 nM/L. 250 had cord blood levels above 200 nM/L. At most 5 of them have an ASD. I presume there will be a study more precisely linking these two data sets.

  15. Aaron S. says:

    I suppose you can respond to people like “diggs” just for kicks…but I doubt you could actually get through. Either this is a worthless troll or a useless ignoramus.

  16. HCN says:

    Aaron, the purpose in responding to “diggs” is often not to change his/her mind, but to show how his/her arguement falls apart so easily to lurkers.

    I am fond of the “sanitation” gambit because it is so easy to refute by:

    1) The fact that better sanitation actually caused polio to become a bigger threat (read Oshinsky’s book “Polio, an American Story”)… or click on the cartoon book I posted of the struggle of a virus called polio (it is really cute).

    2) That Japan has an embarrassing number of measles cases each year since making the vaccine voluntary (college campus had to close last spring in Japan to stem a measles epidemic). It is also the country that decided to delay the pertussis vaccine to prevent SIDS, but in reality more infants died ( ). I am sure Japan is a 1st world country with good sanitation practices.

    By the way, being truthful is not a strong point for the anti-vax bunch:

  17. daedalus2u says:

    Actually the effects of better sanitation are involved in my nitric oxide research, and all the effects may not be so benign. There have been no clinical trials of the actual effects of bathing, so any positive (or negative) effects are purely hypothetical. There is no known mechanism by which bathing per se actually prevents disease. It is only the avoidance of pathogens that prevents disease. Dirt and non-pathogenic bacteria have essentially no known effects on health other than aesthetics. My fundamental hypothesis is that humans evolved with commensal bacteria living on the skin which metabolize ammonia into NO and nitric oxide. These are the very well known autotrophic ammonia oxidizing bacteria. They are universally found in all soils and all natural sources of water where they perform the first step in the process of nitrification, the oxidation of ammonia to nitrite (another type of bacteria oxidizes the nitrite to nitrate).

    As obligate autotrophs they are incapable of growth on any media used to isolate pathogens, which is perhaps why they have not been noticed before. No pathogens are autotrophic; people studying pathogenic and commensal bacteria may have only looked for heterotrophic bacteria. These bacteria happen to be very slow growing, with doubling times 30 times longer than common heterotrophic bacteria. Bathing to remove the heterotrophic bacteria that cause odor likely removes these autotrophic bacteria faster than they can proliferate.

    I think that in the “wild”, before modern sources of running hot water, soap and detergents, humans would have unavoidably and naturally acquired biofilm of these bacteria, and over evolutionary time, humans would have evolved to utilize that NO and nitrite in their physiology. I think that is one reason for non-thermal sweating, such as under stress or in shock. It is to deliver ammonia to the biofilm to supply NO and nitrite (which has enormous protective properties in ischemia in multiple organs). I think that the reason that humans have hair is to provide a niche for these bacteria, on the scalp to protect the brain via flow through the emissary veins and under the arms near the lymph nodes (certainly not to keep the underarm warm!).

    So what does this have to do with sanitation? One of the things that triggers the immune system is a drop in NO, usually this is from the oxidative burst from stimulated immune cells, or from another source of inflammation. A lower NO level will decrease the threshold for activating the immune system. I suspect this is part of the cause of the increase in autoimmune disorders and allergies. The hygiene hypothesis suggests there is some agent removed by living in a developed world, the loss of which is causal in producing immune deviation, but that agent has not been identified. I suggest it may be these bacteria.

    A major mediator of the immune system is NFkB, which is inhibited by NO (and triggered by the drop in NO). When NFkB is activated, it causes the expression of iNOS which can produce large quantities of NO, and is responsible for the hypotension of septic shock. This NO can cause feed-back inhibition of the expression of other nitric oxide synthase isoforms, eNOS and nNOS, which can then lower NO levels after the iNOS is cleared. This is what I call the “low NO ratchet” and discuss in my latest blog.

    Lowering NO levels may have a very modest effect on the course of some diseases by accelerating activation of the immune system by decreasing the trigger for the transition to an oxidative stress state (the immune system activated state). This might (very speculative now) shorten the course of some diseases but may make some much worse by exaggerating the immune response (think SARS, ARDS and the flu of 1918) where it isn’t the disease that kills, but the immune response that is lethal. This might explain some of the very modest reductions in some diseases that were observed before vaccination become common, but it was certainly vaccination that brought about the dramatic reductions to near zero for every disease for which there has been sufficient vaccination.

  18. DLC says:

    The notion that Salk and Sabin said that the decrease in polio cases was not due to vaccinations is the same thing as saying that Charles Darwin recanted on Evolution on his deathbed.
    The entire story is false, in both cases.

  19. Gilbs says:

    HELP PLEASE: Concerned parent from the UK!

    The comments below are not mine, but statements in some literature that I would love answers to, before I allow my two year old boy to have the MMR Vaccine.

    I have read extensivley but find so much conflicting advice. I am quite happy to make a decision in the interests of my childs health providing it is an informed one and not clouded in propaganda from both sides of the debate.

    In the UK the debate always seems to be about the MMR and autism. I am more interested in the requirement to vaccinate per se.

    The perceived wisdom in UK and particularly in the media is that vaccination is necessary and if you do not contribute to the herd immunity, through choice, we are stigmatised.

    How much do the media sensationalise epidemics, go for the lazy headline and misrepresent statistics?

    If for example 100 people are vaccinated and 5 contract the disease is this 95% effective? What if only in fact 10 people were actually exposed to the disease? Then in reality it is 50% effective.

    How does herd immunity break down; if you are vaccinated, you are vaccinated. Is it because the virus mutates and so can spread to vaccinated populations, or loses effectiveness? I understand that the 1989 CDC stats reported that 50% college measles victims were actually vaccinated and 66% school victims were vaccinated.

    When we hear of “epidemics” and scaremongering headlines, we then discover the epidemic is 4 or 5 people at the most. In that “epidemic” how many are vaccinated?

    One further point on the media; according to some literature now, diseases, such as measles, are highly dangerous and can cause death. The language used in the past referred to measles as a mild childhood illness. Are the dangers now exaggerated to scare parents into compliance?

    Also is it conceivable that Doctors do not diagnose correctly? If they note a child has been vaccinated they may assume it is not that disease.

    There is a view that adverse reactions including death due to vaccination is seriously under reported, and a view that vaccine related deaths are significantly higher than the disease deaths. Allegedly in Japan SIDS declined rapidly when their vaccination ages were deferred to 2 years from 2 months

    Why Vaccinate?
    I understand that vaccination is based on 3 Assumptions:

    1) Illness should be avoided
    2) Vaccination is safe and effective
    3) Protective benefits outweigh risk of side effects.

    1) In today’s modern world, most infectious diseases have few serious consequences. Child hood illnesses are benign, self limiting, help mature the immune system, impart lifelong immunity (not temporary like vaccines) and maybe protect against more serious disease in adulthood.

    Isn’t it true that nutrition, exercise, sanitation, lifestyle, quality food and water are very important, and perhaps the main reasons for the decline in the disease and its potency? (yes I have read the sanitation polio comment by HCN)

    2) The immune system is very complex and has evolved over millions of years; the presence of antibodies does not necessarily protect against disease. Vaccinations inject matter directly into deep tissue bypassing the body’s natural defences: skin, respiratory system etc.

    Infectious disease was already declining prior to the introduction of Vaccines. The pretty graphs we often see with the label at the start of a period of decline are misrepresented and come at the end of a steep decline due to improved living standards.
    The diseases DPT vaccinates had already declined by 80% before its introduction.

    Have there been any double/ triple blind studies carried out in vaccines to establish evidence for the efficacy?

    3) Have long term studies been carried out to monitor the effects of vaccination on the immune system and the recipient’s health? Can injecting foreign matter into a young developing immune system have an effect that has not been considered?

    What happens to Adults who had the benefit of temporary protection due to vaccination at child hood and not life long immunity had they caught in naturally? For example Chicken pox in children is relatively harmless; in adults it can lead to shingles.

    Is it valid to part reject germ theory; germs, although a necessary component are not the whole cause of the disease. They in fact infect an already compromised host.

    Instead of allowing a fever to run its cause will aggressive intervention internalise inflammatory responses to disease and thereby result in a less healthy and robust individual.

    Are there links to other conditions such as SIDS, allergies, asthma, behavioural disorders and auto immune related diseases.

    Hib – we have read that this vaccine is still very much in an experimental stage and it is basically ineffective and the best advice is to take your child to nurseries that only have toilet trained children! Yeah right.

    Why do I need to give my children the BCG vaccine when it has been established that the high risk areas are crowded inner city areas particularly amongst immigrant populations; and we have no family history in the last 5 years.

    The message I have derived from this literature, is that if you live in an industrialised country and do not intend travelling outside Europe US etc, particularly in the summer, don’t vaccinate. Vaccination is unnecessary, ineffective and causes a higher incident of damage than is reported.

    So you see as a non scientifically trained parent when presented with this propaganda it is very worring and hard to see the wood for the trees. A little knowledge is dangerous! your comments would be greatly appreciated.

  20. HCN says:

    Read this:,,2087-1061838,00.html

    By the way, did you really understand my comment about Japan and its experience with measles?

    Plus, Hib has been used in the USA for almost 20 years. It is not experimental.

    Most of your questions are answered in this book, including strategies, reasons, and a chapter on each vaccine:

    But more detail stuff you asked: “Why do I need to give my children the BCG vaccine when it has been established that the high risk areas are crowded inner city areas particularly amongst immigrant populations; and we have no family history in the last 5 years. ”

    The BCG vaccine has not been used in the USA. It is fairly ineffective and you should check the NHS website for their policies.

    The other one is “The message I have derived from this literature, is that if you live in an industrialised country and do not intend travelling outside Europe US etc, particularly in the summer, don’t vaccinate. Vaccination is unnecessary, ineffective and causes a higher incident of damage than is reported.”

    That is pure bull. Japan is an industrialized country, but had to close college campuses last spring to stem the tide of a measles epidemic (did you think the only industrialized places were in Europe and North America?). The UK is an industrialized country and has been the source of measles and mumps outbreaks in other countries. Australia is an industrialized country and is experiencing an increase in rubella. The USA is an industrialized country is having an upserge of pertussis (lately in Colorado).

    The folks who are telling you to not vaccinate are leeches who depend on OTHER people to vaccinate.

    You are obviously reading the wrong literature (if the webpage is has “” in it you can be guaranteed that the information in it is completely useless). Next time someone tells you that “Vaccination is unnecessary, ineffective and causes a higher incident of damage than is reported” ask for some details. I have continued to ask these people which vaccine is more dangerous than the actual disease with documented evidence, and I have yet to get a real response.

    Go to the Blogroll on the right side of this page, check them out on the issue of vaccines.

  21. dijital13 says:

    As someone opposed to vaccines (at least for the developed world) at this point, I must say that this site is the first pro-vaccine site I’ve seen that makes some sense as opposed to most that simply cite their unquestioning faith in the CDC and its literature. Because I doubt the reliability of the CDC, those arguments carry little weight with me. So, because it seems there are many intelligent people commenting here, I’d like to ask the following question:

    I’ve worked in the securities industry and am glad that the SEC regulates conflicts of interest so that some bozo (even a smart one) can’t buy call options on Enron and then flood the internet and his clients with strong buy recommendations on it purely for his personal gain. My biggest objection to vaccines thus far has been the incredible financial conflicts of interest that exist for the people who make and/or strongly influence vaccine policy at the CDC. For starters, see this article:

    My question is this: How can you trust any study from an organization (the CDC) and industry with such obvious conflicts of interest? Because there is no regulatory agency pointing out or barring such conflicts, I feel as if I’m left with no good information. Without good information, I am not going to inject neurotoxins into my child on blind faith. Still, I’m frustrated that these conflicts are allowed to exist.

    I’d love to hear anyone chime in on these thoughts.

  22. HCN says:

    digital13 said “My question is this: How can you trust any study from an organization (the CDC) and industry with such obvious conflicts of interest? ”

    Because the studies are replicated in other countries by other public health agencies and by the World Health Organization.

    Despite opinions to the contrary, the Centers for Disease Control is part of the United States of America’s Department of Health and Human Services, not the World Health Organization. It does not create policy in Japan (which is having trouble with measles at the moment), Canada, the UK, Denmark or any other country. It does coordinate with research in other countries.

    Also, most of the research on vaccines is not really done by the CDC, but by universities that may receive funding from various sources. If you go into and put “vaccine” in the search window you will find papers from research all over the globe. If you read Dr. Gorski’s comments you will see papers from Denmark and Canada being referenced, neither country is covered by the CDC.

    Is this a CDC publication:

    And where has the research by Wakefield and the Geiers (and their rubberstamp IRB) been replicated? Why are you more willing to accept lawyer paid research than research paid by public health agencies of multiple countries?

    Then you continue: ” Without good information, I am not going to inject neurotoxins into my child on blind faith. Still, I’m frustrated that these conflicts are allowed to exist.”

    Which neurotoxin are you mostly concerned with? Could you please name it and tell us what injections it is in? Obviously not tetanospasmin, nor diphtheria toxin because you seem to want to avoid the DTaP, DT, Td or Tdap vaccines.

    You started out by saying “As someone opposed to vaccines (at least for the developed world) at this point,”

    Could you please go up to my earlier comment and tell me why Japan and UK are experiencing outbreak in measles, did they lose their “industrialized” country status? Their are now outbreaks of pertussis in various states in the USA, did that country just become a “non-industrial” country? Or are you just one of those folks who likes to use herd immunity for your own benefit? If you are, read my comment before yours, and take it to heart.

  23. Harriet Hall says:


    How can you oppose vaccination in developed countries when there are so many examples from developed countries of diseases recurring and killing children when vaccination rates drop?

    Your comments about the sources of information and about “injecting neurotoxins into my child on blind faith” smack of emotion, paranoia, and conspiracy theories, not of objective analysis of all the available information. My children got all their shots, but not because I had blind faith in anyone or anything; and I have no reason to think they received anything that would constitute a “neurotoxic” danger to them.

    Those of us who have carefully considered the science have come to the conclusion that the small risk of vaccines is far outweighed by the larger risk of not vaccinating. We are not going on faith in the CDC, but on repeated observations from all over the world and from various avenues of research.

    It is true that in a country where immunizations have practically eliminated the diseases, an individual child may not benefit from vaccines; but as the number of unimmunized children rises, the risk rises for all, even those who have been immunized. People who opt to refuse vaccines are endangering the public health of all of us.

  24. HCN says:

    I would also like to remind digital13 that herd immunity will not protect any of his children from tetanospasmin, a known neurotoxin. But a vaccine will.

    Just saying…

  25. Gilbs says:

    Thank you for the links and taking the time to respond, it is appreciated. By the way please include all other industrialised countries in the “etc” bit of my post ;-)

  26. biggs_f says:

    Ok, I think you “proved” vaccines do not “cause” autism. However, I am not sold that there is no epidemic; that th alarming rates are merely due to the umbrella catchall classification/diagnosis of autism.

    There IS some sort of environmental factor causing these brain alterations, or turning on the autism gene – and I would like to see more hypotheses proposed rather than debunked.

    Has there been any research done on any correlation between autism and BHT (food additive), MSG (monosodium glutimate), aspartame, or even aluminum zirconium???? All of these are known toxins which I challenge any one of you to prove to me is NOT in your household or everyday diet. All of these are known to have some affect on brain chemistry – is it suc a far leap to hypothesize that they could possibly play some role in the development of autism?

  27. HCN says:

    You are grasping at straws now!

    How about you look in and tell us what you find?

    While you are at it, take a look at Japan and tell us what happens when vaccine coverage is reduced.

  28. daedalus2u says:

    There is an environmental factor that does “explain” an autism epidemic (if there actually is one), that would be bathing. Bathing removes commensal bacteria. The ones that I am working with are autotrophic ammonia oxidizing bacteria which oxidize ammonia into NO and nitrite.

    During industrialization one of the first things that is produced is clean water which is used for bathing which removes these bacteria. In the 1960’s, the advent of alkylbenzene sulfonate synthetic detergents (which kill these bacteria at ppm levels) was the second hit. The third hit was the advent of conditioning shampoo, which allowed individuals to wash their hair every day instead of once a week. The fourth hit is the addition of antibacterial crap to everything.

    How often did people bath 10,000 years ago? Likely never in their entire lives. Has there ever been a study showing the long term effects of bathing? No, there hasn’t been. It is simply assumed to be benign, even “good” for you.

    There is plausible physiology connecting low NO with ASDs. There is none connecting mercury with ASDs. Why is the wrong mercury idea still being pursued? Because some quacks are making a lot of money at it. Because some quacks are hoping to win the “legal lottery” by tricking the Vaccine Court into believing that vaccines cause autism.

    You think there is a conflict of interest for the CDC (which doesn’t make or sell vaccines) but none for the quacks who sell chelation, HBOT, secretin, lupron, and all the other biomedical crap? What planet are you on?

  29. Calli Arcale says:

    Personally, as the mother of a child who very likely has a form of autism (no formal diagnosis as of yet, but she qualifies for services; at this point I don’t feel she’d be well served by a medical diagnosis anyway, as her case is clearly pretty borderline), I would be interested in knowing more about why autism rates have risen so much. There is an eerie similarity in the rates of papers on autism and autism diagnoses — that might argue for a “better recognition/broadening criteria” explanation. But I’ve wondered if some of it is increasing literacy.

    Now don’t get me wrong: literacy is *awesome*. But I wonder if some of these cases of autism would’ve gone unrecognized in the days before widespread advanced education. Heck, many cases might not even have been a problem. It is now very unusual (in the US/Canada/UK/Europe/Japan/etc) for a person to *not* graduate from high school, or at least obtain some sort of equivalency diploma. A lot of times, the borderline cases of autism are noticed through the educational system, as the child has difficulty following along in class and cooperating with the rigid class schedule that is so necessary when you have to teach a couple dozen kids at once. Furthermore, communications skills (or lack thereof) are a large part of an autism diagnosis, and the first place where communication becomes really critical is in school. So I wonder if this explains some of the increase?

    As far as vaccines go, there is plenty of evidence. You don’t need to trust the experts; you can read the actual studies. (Yes, they have been done.)

    Regarding the risks of childhood diseases being small, you ought to consider that before vaccines were introduced, families tended to have lots of children because so few would make it to adulthood. Childhood diseases can kill, and even nowdays they still do. Even chickenpox, which a lot of people casually dismiss. Chickenpox is usually thought of as an annoyance where you end up having to sit at home for a week and take a lot of warm baths to help the itching. But it can be disfiguring, it can cause permanent paralysis or other nerve damage, it can blind, and it can even kill. And does. People die of it even in the US. And shingles? One of the nasty things about varicella (the virus behind chickenpox) is that when you get over the disease and are no longer contagious, it’s no guarantee that you’re actually free of it. It can hide out in nerve endings for decades before something provokes it into activity. (I don’t think scientists have worked out exactly what triggers it.) Shingles can result from that, without any new exposure to chickenpox. And this recurrent shingles isn’t just an annoyance; it, too, can kill. It can certainly disfigure; it’s a major cause of Beall’s Palsy (where a particular nerve to the face becomes paralyzed, causing that half of the face to droop). Interestingly, a study of the chickenpox vaccine in the elderly showed that it reduced the rate of shingles infections and their severity — even in people who had previously gotten chickenpox. I wish I had a citation for that, but I don’t. It was intriguing, though.

    Regarding the Hib vaccine, Haemophilus influenza b is a very dangerous pathogen, especially for small children. Staying away from babies in diapers will not protect you from it. It is contagious, and can cause such things as meningitis. I may even have had it as a child. (I’ll never know, since through an accident, the hospital lost the sample of my cerebrospinal fluid. Since they didn’t want to subject me to another tap, they put me in isolation in case it was Hib until I got over the worst of it.)

    Regarding herd immunity, this is needed to protect those who can’t get the vaccine (some are allergic to components in it, or are immune compromised), those who won’t get the vaccine (yes, the CDC still cares about them), and those for whom the vaccine will not “take”. Vaccines work fairly well, but the immune system doesn’t always recognize the pathogen in the desired fashion. (People’s immune systems vary. Even getting the actual disease doesn’t always produce immunity. I’ve had chickenpox twice, for instance.)

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