Actions have consequences, as do beliefs. For example, the widespread erroneous belief among many parents of autistic children that the mercury in the thimerosal preservative that was used in most childhood vaccines until 2002 somehow caused autism in their children have led some pseudoscientists and parents who have fallen under their sway to subject their children to all manners of "biomedical" interventions to "extract" the mercury and supposedly cure their children of autism. In extreme form, this belief has led to highly dubious "treatments" such as those served up by Mark and David Geier, in which strong chelating agents are combined with Lupron, a powerful drug that blocks sex hormone synthesis, in order to decrease testosterone, which they claim with no good scientific justification forms "sheets" that "bind" mercury, making it supposedly "harder" to chelate. The Geiers have even applied to patent their new "treatment," just going to show that just because something's patented does not in any way guarantee that it's not a load of fetid dingo's kidneys.
Nearly two years ago, we found out that chelation therapy is not without risks, when a DAN! "practitioner" named Dr. Roy Kerry, an otolaryngologist who apparently discovered that woo pays, managed a clean kill of an unfortunate 5 year old autistic boy named Abubakar Tariq Nadama through chelation therapy. What happened is that Dr. Kerry's staff administered sodium EDTA by IV push without cardiac monitoring, leading to a rapid decline in the calcium in the boy's bloodstream (EDTA attaches to calcium ions as well as mercury and other heavy metals) leading to heart rhythm disturbances. This is a known risk of chelation therapy, which is why even the DAN!-preferred and supposedly "safer" chelation agent, Calcium disodium EDTA (Versenate) has warnings not to give it IV push and stating that the patient should be on a cardiac monitor while receiving IV chelation therapy. Indeed, Dr. Kerry's horrific negligence leading to Tariq's death has brought him under the scrutiny of the Pennsylvania State Medical Board. Unfortunately, that was back in October, and, as far as I can tell, Dr. Kerry continues to practice. Although I have no way of knowing for sure, it's certainly possible that he may even still be chelating autistic children, despite the fatal incompetence and recklessness revealed in his own notes on the Nadama case.
It would appear, however, that, even if his state medical board doesn't get Dr. Kerry, the tort system might:
The parents of a 5-year-old autistic boy who died after receiving a chemical treatment sued the doctor who administered it for wrongful death.Mawra and Rufai Nadama, who live in Britain, accused Dr. Roy Kerry of causing their son, Tariq, to die of cardiac arrest at Kerry's office immediately after the boy received chelation therapy on Aug. 23, 2005.
[...]
The Nadamas are also suing ApotheCure Inc., of Dallas, which they contend supplied the chelation solution but allegedly did not provide appropriate warnings and instructions about its use.
The company did not immediately return a call for comment.
The complete complaint here. Key passage:
Prior to treating Tariq Nadama, Dr. Kerry was specifically aware that:
a. There were no generally accepted medical studies proving that chelation therapy offered any beneficial treatment of autism. Despite such knowledge, he knowingly and intentionally ordered such treatment for Tariq Nadama.
b. The only FDA approved use of disodium EDTA was for treatment of patients with hypercalcemia (high levels of calcium) or digitalis toxicity, neither of which Tariq had. Despite such knowledge, he knowingly and intentionally ordered such treatment for Tariq Nadama.
c. He had never used EDTA therapy on a child. Despite such knowledge, he knowingly and intentionally subjected Tariq to chelation treatment with EDTA.
That one's going to leave a mark!
Despite my schadenfreude at seeing Dr. Kerry get more grief, I'm conflicted about this new development. As much as a huge malpractice judgment against Dr. Kerry would satisfy my sense that at least some justice had been done and that he had escaped with more than just a slap on the wrist for professional behavior that is disgraceful and disgusting, this lawsuit bothers me. The reason it bothers me is because the parents share in the responsibility for Tariq's death. They sought out a practitioner to administer chelation therapy to their child. They brought Tariq to the Pittsburgh area from the U.K. to have Dr. Kerry treat their child. But what really causes me a bit of conflict over this development is that Tariq's father, Rufai Nadama is a physician who was working in the British NHS as a specialist registrar in respiratory medicine at the time of his son's death. These were not your run-of-the-mill unsophisticated parents without medical knowledge or training. That does not in any way excuse Dr. Kerry for his actions and his almost certainly not giving full informed consent before starting chelation therapy, but it does make one wonder. On the other hand, the Nadamas stated quite clearly right after Tariq's death that they would not sue. Perhaps the findings of the Pennsylvania State Medical Board thus far have opened their eyes.
Moreover, they appear to be suing not just Dr. Kerry. Indeed, they've learned the American way rather quickly and are now everyone and everything in sight:
The Nadamas are also suing another doctor who allegedly directed a medical assistant to administer the fatal dose at Kerry's behest, as well as ApotheCure Inc., of Dallas, Texas, and several sister corporations, which they contend supplied, made or tested the chelation solution but did not provide appropriate warnings and instructions about its use. ApotheCure did not immediately return a call for comment.
The Nadamas have suffered what is the worst tragedy that a parent can suffer, the death of their young child. Worse, the wheels of justice seem to be turning very slowly as far as Pennsylvania's taking action against Dr. Kerry. Seeing them go after him in the civil courts raises at least the possibility that justice will be served and is satisfying for that reason. Even better, this lawsuit could serve a greater purpose. Through the process of discovery, it will allow the plaintiffs to uncover the dubious at best and possibly illegal activities of the chelationistas and their suppliers. It might even deter some families from seeking out chelation. However, my satisfaction is twinged with a queasiness that comes from knowing that the Nadamas themselves share in the blame for this tragedy.
However, my satisfaction is twinged with a queasiness that comes from knowing that the Nadamas themselves share in the blame for this tragedy.
Perhaps they do, but at the very least this has the potential to do for (or to?) mercury what the Cedillo case did for (or to) MMR.
How are the final deliberations going in that case, BTW? Seems to me the defence wrapped their argument up very well and handed the prosecution its arse for lunch.
I hope that what the Geiers are doing with Lupron comes out.
wow! A malpractice case that actually is malpractice! Don't see that very often.
Orac,
Let me first say that I greatly enjoy your blog and it was good to hear you over on the Skeptics Guide last month.
However, don't you think you are being a bit hypocritical with this post? You railed against the "broken tort system" a couple months ago: http://scienceblogs.com/insolence/2007/05/our_broken_tort_system.php
Now when you happen to agree with the Plaintiff, it is a method for serving justice! You simply can't have it both ways. And by the way, justice was served in the "pants" case although I haven't seen a follow up from you--did I miss it?. The crazy judge has to pay the Chungs' court costs and is probably going to be on the hook for their legal fees, not to mention that he is probably going to be out of a job. Now that's justice!
Your posts remind me of the surveys that show people often have a low opinion of Congress but think their Congressmen is doing a great job. People think the legal system is out of control yet they generally think their lawyer is doing a fine job for them and they don't actually know anyone who has been on the wrong end of a really bad lawsuit. Of course they can tell you about one they heard about on TV or read in a newspaper...
Orac, good notes.
(1) Disabusing folks of the putative link between Autism and mercury requires use of many tools--including legal ones--and repeated reminders. Thanks for keeping the topic alive.
(2) About malpractice suits: Some who practice malpractice law contend that such suits help to purge incompetents from professions. Other folks might say that the tool is used too often and too broadly. This reminds me of the potential for harm that a certain sharp instrument has: Scalpels can be used for surgery or....
Malpractice is a poor way to patrol a profession because it does not count on true quality measures...it measure more whether a patient likes a particular doctor. It also inhibits error-reporting by docs. There have been all sorts of proposals for professional panels and award pools for true victims of medical error.
Anyway, I'm glad that quack chelator is getting his ass sued. I would prefer to see him criminally prosecuted for using not and unproved treatment, but a DISPROVED treatment to kill a patient. These people prey on hope and fear, so it's hard to blame the parents, as NO ONE is sophisticated when it comes to their own child.
He told the paper he believed "genetics, better recognition of the condition, environmental factors and children's exposure to hormones, especially testosterone in the womb, were more likely to be the cause of autism". Who said this?
(A) Simon Baron-Cohen (world renowed autism expert
(B) Mark Geier (accused of child abuse for lowering testosterone in autistic kids
(C) A lawyer
(D) non of the above
answer. (A) Simon Baron-Cohen
Uh-huh. SBC is certainly entitled to his <>beliefs but he doesn't administer Lupron to pregnant moms based on his beliefs, does he? What's your point?
Kevin Leitch is collecting common autism-vaccination etc. canards and their rebuttals that people can use as a resource both on his blog and more generally. Write up your favourite ones and send him the link.
Or, I suppose, it might be easier to name a topic and then search through Orac for the links, put it together in an easy to read format, and send that along to Kevin.
They also relied on a doctor to tell them which treatments were safe and effective for their child's condition and that doctor lied to them, selling them a treatment which was neither.
It is precisely because people who don't have years of medical training trust the ones who do, that we have lawsuits like this for when the people with the training don't apply it and instead sell their patients a dangerous quack treatment.
Laypeople rely on the judgments of professionals in complex fields that they themselves don't understand. That's why we hold doctors to a higher standard than patients when it comes to making stupid medical decisions. The doctor should have known better - or he *did* know better, which is worse.
Orac:
I think you are engaging in sensationalism and not providing the whole story.
I think this doctor was negligent, I certainly don't blame the Nadamas for suing, and I hope they get some justice, which will never come close to the loss they have endured.
But, anyone in the DAN! community knows not to give Sodium EDTA in an IV and no one uses this drug. To the extent IVs are done, they are done with Calcium EDTA, which is entirely different. Is it really fair to paint all of chelation as bad because one doctor used the wrong drug?
Using this single story to state that "chelation is dangerous" would be no different than me pointing out the hundreds of deaths due to Ritalin and saying that ANY use of Ritalin is dangerous and stupid.
If you want to position yourself as a "scientist", more balance in telling the story of Tariq is warranted.
Also, a few questions for you:
- Can a person be "heavy metal toxic"?
- How would one measure for that?
- What would be the appropriate course of action be if a child were heavy metal toxic?
For the sake of argument, and let's put vaccines aside for just a moment, what if autistic children were universally burdened with a malfunctioning detoxification system in their bodies and by the very act of living, were building up more toxins on a daily basis than NT kids? What, as a doctor would you do about it?
And, by the way, have you seen any literature that might support this idea, this idea that our ASD kids are carrying heavier toxic loads than their neurotypical peers? You know, like:
Porphyrinuria in Childhood Autistic Disorder: Implications for Environmental Toxicity
Toxicology and Applied Pharmacology, 2006.
Robert Nataf, Corinne Skorupka, Lorene Amet
A Case Control Study of Mercury Burden in Children with Autism Spectrum Disorder.
Journal of American Physicians and Surgeon, 2003.
James Adams, PhD [Arizona State University].
A Case Series of Children with Apparent Mercury Toxic Encephalopathies Manifesting with Clinical Symptoms of Regressive Autistic Disorder
Journal of Toxicology and Environmental Health, 2007
David A. Geier, Mark R. Geier
Attention-deficit hyperactivity disorder and blood mercury level: a case-control study in chinese children
Neuropediatrics, August 2006
P.R. Kong [Department of Pediatrics and Adolescent Medicine, The University of Hong Kong].
So, really, help me out. Can "heavy metal toxicity" be measured in your mind? And, if it can, is any treatment warranted? And, if so, what might that treatment be?
As you ponder what Tariq's Dad, a physician himself, was thinking, perhaps he had clear information which told him his son was over-burdened with metals? Perhaps his only mistake was not knowing the difference between Sodium EDTA and Calcium EDTA? Perhaps if you talked to Tariq's Dad, you would feel differently.
JB Handley
Chris -
But the kids dad is a doctor, while he may not be a specialist at dealing with autism, neither is he a total lay person. Presumably, he too has had years of medical training. I say this not to excuse what Kelly did, but because it adds to a lot of red flags. I find it incredibly hard to believe that these folks didn't know that this was, at the least, a very unconventional treatment. If they didn't, why not have it done closer to home? There are just too many red flags for me to be very comfortable with this.
To be honest, there are enough red flags for this "treatment," that I would think even complete laypersons should at least be suspicious enough to look into it further. This from someone who uses plants for pain and sleep management, on occasion. I trust doctors, because I have to. That doesn't mean that I do, or anyone should, trust every doctor, or any single opinion, when the stakes are high.
PalMD wrote: "[The tort/malpractice system] also inhibits error-reporting by docs."
I'd really love to see the institution of malpractice protection in return for more thorough and open error reporting and self-policing of doctors, but proposals along these lines have routinely been shot down by organizations of medical professionals. I'm sure the malpractice bar isn't in love with the idea either.
JBH: "As you ponder what Tariq's Dad, a physician himself, was thinking, perhaps he had clear information which told him his son was over-burdened with metals?"
Clear, perhaps, but not at all accurate. No doubt the same pseudoscientific 'studies' like the few you've cited above. No doubt provided by pseudoscientific organizations such as your own by idiots who prefer press releases and phone surveys over legitimate science.
While we are citing the Geiers, how long do you intend to host their "Downward early trends" pack of lies now that you know full well autism rates aren't heading down any time soon?
JBH: "For the sake of argument, and let's put vaccines aside for just a moment..."
No JB. Sorry but you don't get to put vaccines aside. It's always been all about the thimerosal for you and Denigration Rescue. You don't get to put all of those years of ranting aside until you finally admit your errors and publicly state that thimerosal has nothing to do with autism. I doubt that will happen any time soon.
Hi JBH,
"For the sake of argument, and let's put vaccines aside for just a moment, what if autistic children were universally burdened with a malfunctioning detoxification system in their bodies and by the very act of living, were building up more toxins on a daily basis than NT kids?"
Having made that assumption, we should probably proceed to test it agaisnt reality. This statement is useful, because it makes a testable prediction. And when we do test it, we can see it doesn't work.
Williams, G. P., Hersh, J. H., Allard, A., & Sears, L. A. (2007). A controlled study of mercury levels in hair samples of children with autism as compared to their typically developing siblings. Research in Autism Spectrum Disorders. In Press.
Soden, S, E., Lowry, J, A., Garrison, C, B., Wasserman GS. (2007). 24-hour provoked urine excretion test for heavy metals in children with autism and typically developing controls, a pilot study. Clinical Toxicology, 45(5), 476-481.
Also, related to this topic, your organization just invested an admirable amount of time and money into a survey of vaccinated and unvaccinated kids. Orac, Prometheus, and Kev all wrote interesting responses to the interpretation of your results. I was especially surprised that Promethues found that the difference in terms of autism was not statistically significant between groups. When I ran the same test, I came to the same conclusion as Prometheus. Any thoughts?
Mr. Handley, I think you are engaging in sensationalism and not providing the whole story when you say that "anyone in the DAN! community knows not to give Sodium EDTA in an IV and no one uses this drug." If that was true, then DAN! would distance itself from the American College for Advancement in Medicine (aka ACAM), whose chelation protocol Kerry was following when he killed that boy.
And why is Kerry a DAN! doc now? Is killing kids part of the entrance exam?
1 ppb mercury = Kills human neuroblastoma cells (Parran et al., Toxicol Sci 2005).
2 ppb mercury = U.S. EPA limit for drinking water (http://www.epa.gov/safewater/contaminants/index.html#mcls)
20 ppb mercury = Dendritic cells damaged, calcium channels interrupted (UC-Davis MIND Institute, 2006).
200 ppb mercury = level in liquid the EPA classifies as hazardous waste http://www.epa.gov/epaoswer/hazwaste/mercury/regs.htm#hazwaste)
600 ppb mercury = Level in a currently licensed Hepatitis B, multi-dose vaccine vial, labeled as trace. This is administered at birth.
2,000 ppb mercury = 0.50-mL injections of Thimerosal-containing vaccines (FDA CBER's definition of "trace").
25,000 ppb mercury = Concentration of mercury in multi-dose, Hepatitis B vaccine vials, administered at birth from 1990-2000 in the U.S. Not administered at birth in any other developed country.
50,000 ppb mercury = Concentration of mercury in DTaP and Haemophilus B vaccine administered 8 times in the 1990's to children at 2, 4, 6, 12 and 18 months of age.
Current "preservative" level mercury in flu, meningococcal and tetanus (7 and older) vaccines.
Gee Tim, care to explain the significance of those numbers in in the context of autism?
Start by telling us (in ppb of course) the average peak concentration of mercury in the blood stream following vaccination with a thimerosal containing vaccine followed by the concentration in the central nervous system.
Maybe you can plot (in ppb of course) the rate of Hg clearance and how any of those concentrations are relevant in vivo.
Perhaps you can tell us the blood levels required before a responsible physician might order chelation therapy under advice of a clinical toxicologist.
Is there any reason to believe that these levels can cause neurological effects resembling autism or that chelation can reverse those effects?
1. You do realize that if you take something at a particular concentration and inject it into a person with volume larger than a vaccine, it gets diluted, right?
2. Which definition of "mercury" are you using?! I think we can expect quite a lot of wiffle-waffling on that. Am I going to have to explain to you that salt isn't a green poisonous metallic gas that tends to react explosively with water while we're at it?
NM, I can't answer what the safe level of injected organic mercury is for newborns, pregnant women and infants. You should probably go to the FDA site where I'm sure multiple studies have been carried out to determine this. When you find them can you provide a reference. According to a published paper on your blog, 33.2 ug Hg/ gr creatine would be an amount that would require a couple of months chelation. I have seen hundreds of lab reports from autistic kids where the mercury level exceeds this.
NM, I can't answer what the safe level of injected organic mercury is for newborns, pregnant women and infants. You should probably go to the FDA site where I'm sure multiple studies have been carried out to determine this. When you find them can you provide a reference. According to a published paper on your blog, 33.2 ug Hg/ gr creatine would be an amount that would require a couple of months chelation. I have seen hundreds of lab reports from autistic kids where the mercury level exceeds this.
NM, I can't answer what the safe level of injected organic mercury is for newborns, pregnant women and infants. You should probably go to the FDA site where I'm sure multiple studies have been carried out to determine this. When you find them can you provide a reference. According to a published paper on your blog, 33.2 ug Hg/ gr creatine would be an amount that would require a couple of months chelation. I have seen hundreds of lab reports from autistic kids where the mercury level exceeds this.
Tim, Tim, & Oeo: "I can't answer what the safe level of injected organic mercury is for newborns, pregnant women and infants."
That wasn't the question.
To Interverbal:
Kev wrote an interesting response to our survey? Yeah, right. In Kev's world, if prevalence is 3% in one group and 1% in another, that's a difference of 2%. Kev showed the math skills of a bipolar 6 year-old.
Prometheus sliced the data until he could rest on one comparison that didn't meet 95% C.I., and I don't believe Orac analyzed the numbers, but I could be wrong. None of them acknowledged any of the meaningfull conclusions that did meet both 95% and 99% CIs. So be it, many equally qualified statisticians reviewed the work and reached different conclusions.
If you are willing to remove bias, our work showed a demonstrable difference between vax and unvax kids on many different things. We appropriately qualified the limitations of our study, and our point that more work on this topic should be done is reasonable to anyone trying to look at this issue in a non-partisan way.
No one has answered my relatively simple question: is there an acceptable way to measure toxic body burden? If so, what is it? and, if your child meets the criteria for being "toxic", what do you do about it?
Are there any Doctors in the house who have a clue? Orac, you must know. Don't you?
JB
"Porphyrinuria in Childhood Autistic Disorder: Implications for Environmental Toxicity
Toxicology and Applied Pharmacology, 2006.
Robert Nataf, Corinne Skorupka, Lorene Amet"
Is that the Robert Nataf who part owns the lab that runs the testing this paper recommends? And there's me thinking you weren't a fan of people who had financial conflicts Brad.
Interesting that you've also 'forgotten' to put Richard lathe's name on this paper. He is the secondary author. Is that because he has already admitted the shortcomings of this paper?
"A Case Control Study of Mercury Burden in Children with Autism Spectrum Disorder.
Journal of American Physicians and Surgeon, 2003.
James Adams, PhD [Arizona State University]."
Not a proper journal. Please try again.
"A Case Series of Children with Apparent Mercury Toxic Encephalopathies Manifesting with Clinical Symptoms of Regressive Autistic Disorder
Journal of Toxicology and Environmental Health, 2007
David A. Geier, Mark R. Geier"
The Geier's? Really? A pair of plagiarists? This paper is an attempted replication of Nataf and suffers from the same shortcomings. Do you know what they are?
"Attention-deficit hyperactivity disorder and blood mercury level: a case-control study in chinese children
Neuropediatrics, August 2006
P.R. Kong [Department of Pediatrics and Adolescent Medicine, The University of Hong Kong]."
Sorry, what does ADHD have to do with autism?
Lets turn back to your fabulous 'study' for a moment. Didn't you find it interesting that amongst the aggregated 11 - 17 year olds (the cohort you stressed as important) the only difference between non vaccinated and fully vaccinated subjects who had any form of ASD was a 1% difference in the Aspergers kids - or, to put it in language you understand better - the trailer dwelling coo-coos. PDD-NOS, autism and ASD had no differences whatsoever. How come you didn't talk about that on your advert?
I couldn't address it in my advert because then people would know what a fraud I am. That's why you people frighten me so - you see right through me. Why do you torture me so?!? Why don't you leave alone, to pursue advantageous business relationships in my own way!
"Prometheus sliced the data until he could rest on one comparison that didn't meet 95% C.I.,"
If you folks are going to aggregate multiple sub-groups, then you are increasing the odds of a type I error. Most simple statistical tests aren't going to be appropriate here. You would need a MANOVA or something similar.
Prometheus as you say "sliced the data", and made it a fair test using a T-test.
"If you are willing to remove bias, our work showed a demonstrable difference between vax and unvax kids on many different things."
I am not denying there is a difference. However, I would ask whether the difference is shown to be statistically significant, using appropriate tests.
Also, as to bias, your research found a much larger prevalence than what we might have supsected via the epidemiology. Further, the ratios of Autistic Disorder to PDD-NOS are very skewed when compared to epidemiology. Any thoughts as to why this might be, or what this does to the validity of your findings?
"We appropriately qualified the limitations of our study"
Yes you did, but given the limitations of your study, I am surprised that you felt your efforts justified more work in this area.
"and our point that more work on this topic should be done is reasonable to anyone trying to look at this issue in a non-partisan way."
Is it? If I were to show these results to an unbiased stats person, would he agree with you?
Also, as to toxicity, if your child is shown to be toxic for a chemical using reliable and valid detection methods, then you should treat him using researched and proven methods.
"Kev showed the math skills of a bipolar 6 year-old."
Well, a bipolar 37 year old actually.
Is it possible you still don't get:
a) How unbelievably poor your study data is?
b) And that, if taken at face value, it totally undermines any and every point you have been making for the past three years regarding vaccines and autism?
Brad,
A voice of insight here. I think that when you started this survey you must have been under the impression that all autistic children had received the full complement of vaccines. So, when you started the survey, you thought it would be a great beginning to get a phone list of a major autism org in your area. After all, when you called all those parents, you were expecting to hear that all those autistic kids were fully vaccinated, no?
But then, surprise, surprise. Many of the autistic kids weren't vaccinated at all. Or were partially vaccinated. So, then you had the marketing/survey people try to call random parents. And you kept calling until the budget ran out and/or you barely reached some kind of tiny significance factor correlating autism with vaccines in one group. That was what you were looking for, and you went ahead and did your press release.
This scenario fits precisely with the results of your survey. The number of autistic kids you found is about 10x the normal prevalence, even given the fake UK reports presently circulating. Am I right about this scenario?
And here's something for you to consider, Brad. Who are the people who avoid vaccines for their children? Read this and weep. Because the people who are most likely to avoid vaccines for their kids are precisely the same ones who are most likely to have kids diagnosed with autism. And moreover, how many phone calls did they have to make? "A total of 151,720 children . . ." Could get a bit expensive, I guess.
Pediatrics. 2004 Jul;114(1):187-95. Links
Children who have received no vaccines: who are they and where do they live?Smith PJ, Chu SY, Barker LE.
Centers for Disease Control and Prevention, National Immunization Program, Atlanta, Georgia 30333, USA. psmith3@cdc.gov
CONTEXT: Each year 2.1 million children 19 to 35 months of age are undervaccinated. Among these are children who have received no vaccinations. Unvaccinated children are at increased risk of acquiring and transmitting vaccine-preventable diseases. OBJECTIVES: To assess whether the characteristics of children with no vaccinations differ from those of undervaccinated children, to monitor trends in the numbers of unvaccinated children, and to identify states with high rates and counties with large numbers of unvaccinated children. DESIGN: A nationally representative probability sample of children 19 to 35 months of age was collected annually between 1995 and 2001. Vaccination histories were ascertained from children's medical providers. Undervaccinated children had received > or =1 dose of diphtheria-tetanus-pertussis, polio, measles, Haemophilus influenzae type b, hepatitis B, or varicella vaccine but were not fully vaccinated. Unvaccinated children were children who were reported as having no medical providers and having received no vaccinations or children whose medical providers reported administering no vaccinations. PARTICIPANTS: A total of 151,720 children sampled between 1995 and 2001, 795 of whom were unvaccinated. RESULTS: Undervaccinated children tended to be black, to have a younger mother who was not married and did not have a college degree, to live in a household near the poverty level, and to live in a central city. Unvaccinated children tended to be white, to have a mother who was married and had a college degree, to live in a household with an annual income exceeding 75,000 dollars, and to have parents who expressed concerns regarding the safety of vaccines and indicated that medical doctors have little influence over vaccination decisions for their children. Unvaccinated children were more likely to be male than female. Annually, approximately 17,000 children were unvaccinated. The largest numbers of unvaccinated children lived in counties in California, Illinois, New York, Washington, Pennsylvania, Texas, Oklahoma, Colorado, Utah, and Michigan. States that allowed philosophical exemptions to laws mandating vaccinations for children as they entered school had significantly higher estimated rates of unvaccinated children. CONCLUSIONS: Unvaccinated children have characteristics that are distinctly different from those of undervaccinated children. Unvaccinated children are clustered geographically, increasing the risk of transmitting vaccine-preventable diseases to both unvaccinated and undervaccinated children.