The beauty of vaccinations is that they use the body's natural defense system to ward off death and disability.

"Catching" Autism

Are there likely to be any children on earth, even a very tiny group, who have "caught" autism from a measles vaccine, given the fact that the measles vaccine is a crippled version of the wild virus?

First off, it is possible, as vaccine critics point out, to acquire autism. We know that a perfectly healthy baby in the womb can become autistic if his mother catches German measles; we know that perfectly healthy babies whose mothers took thalidomide during pregnancy became autistic: we know that a perfectly healthy young child can emerge from a case of encephalitis with brain damage and autistic-like symptoms, though these children are far more likely to appear simply retarded.

It is even possible, Oliver Sacks writes. though extremely rare, for a healthy adult to become autistic-like after a case of encephalitis. Some of his Awakenings patients, Sacks observes, had "elements" of autism.

And we know that measles can cause encephalitis. It stands to reason, then, that there exists a small subset of people with autism today who may have become autistic after having caught the measles and developed encephalitis as a complication. The question is: can the measles vaccine cause autism?

The Measles Vaccine and Autism?

We do have answers to this question. The National Childhood Vaccination Injury Act of 1986 mandated that the Institute of Medicine (IOM), a private, independent nonprofit organization that advises the federal government on health policy, review evidence regarding adverse reactions of all vaccines administered to children. its findings on the measles vaccine are these:

Between 5 and 15 percent of children vaccinated against measles develop a fever 5 to 12 days afterwards from which they fully recover. Transient rashes have been reported in approximately 5% of children vaccinated. For parents in our community this is the important finding: central nervous system conditions-meaning conditions such as encephalitis that can cause brain damage-occurred in fewer than one per one million doses administered. In reality, a figure this tiny is impossible to interpret the one- per-one- million number could be pure coincidence since we know that children who have not received a measles vaccination actually have a higher rate of encephalitis! "Encephalitis of unknown origin," meaning a case for which no one can find a cause, can and does happen to small children, with or without vaccine. One day the child is healthy; the next he or she is fighting for his life.

What about an even smaller group of children, small enough to escape detection by the IOM -smaller even than one-in-one-million - who might have the specific syndrome suggested by Wakefield and his colleagues?

Criticism of Wakefield's Report

The publication of Wakefield's report has provoked a storm of criticism, much of it published in the Lancet itself, and the validity of the Wakefield findings has been seriously questioned on a number of grounds. Some critics even question whether it should have been published at all, given its preliminary status and given the prediction among public health experts that its publication and the resulting publicity would cause a decline in vaccination rates. Not surprisingly, health officials in Wales (UK) have already noted such a decline.

Some critics believe that there may have been "ascertainment bias" in the selection of study subjects. Wakefield et al state that the study group was comprised of a consecutive series of children with both chronic enterocolitis and regressive developmental disorder who had been referred to the department of pediatric gastroenterology at the Royal Free Hospital and School of Medicine in London. There is no statistical meaning in the fact that all subjects had both conditions-they were selected to participate for this very reason. But, critics suggest, there might also be no statistical meaning, due to ascertainment bias, in the fact that such a high percentage of the subjects also had experienced an observable response to MMR vaccine. Although the high rate of MMR vaccine reaction in these children was presented as a finding, it may have been due to the fact that the pool of clinic patients from which study subjects were chosen might have contained a disproportionately large number of patients with prior MMR vaccine response. It had been known in the community that Wakefield's team had a special interest in studying the relation of MMR vaccine and inflammatory bowel disease. Thus, patients with inflammatory bowel disease (and possibly other conditions as well) who were also known to have had a vaccine response may have been referred specially to that clinic. Such biased case-ascertainment would exaggerate the significance of associations found in the study.

Had Wakefield's team been known to be interested in studying an association between IBD and blue eyes, for example, disproportionately large numbers of patients with IBD and blue eyes might have been referred to the clinic. If, then, a consecutive series of IBD patients was selected for study, the research findings might indicate an exaggerated association between IBD and blue eyes.

Critics point out that the most common endoscopic and/or pathological finding in this study group - ileal lymphoidnodular hyperplasia - is also observed with significant frequency in the general pediatric population, both in connection with a variety of non-specific bowel complaints and without any corresponding symptomology. They suggest that, in the absence of evidence of a causal relationship between IBD and neurodevelopmental disorder, the observed occurrence of these conditions in this study population may be coincidental.

Critics also note the absence of any evidence of a causal relationship between MMR vaccination and IBD and/or pervasive developmental disorder (such as. for example, a finding of measles virus or measles vaccine fragments in intestinal tissue) as well as the absence of suitable study controls. These factors, along with possible ascertainment bias, create the likelihood that the observed associations are merely coincidental.

While the Wakefield report does describe a process by which MMR vaccination might cause IBD, which in turn might cause neuropsychiatric dysfunction, evidence presented in the report seems to contradict this theory: the observed onset of symptoms of IBD seems to occur significantly after, not before, the onset of behavioral symptoms.

The Wakefield report states that all twelve study subjects have regressive developmental disorder and that eight of them were observed to have begun to exhibit behavioral problems shortly after an MMR vaccination. The validity of using retrospective reports, mainly of parents, to establish a strong temporal association between vaccination and onset of neurodevelopmental disability is questioned by some critics.

While it may be a bit demoralizing, it is well known that our memories are not accurate enough to support medical hypotheses one way or the other. Researchers have conducted studies in which then, cross-checked parents' accounts of their children's medical histories with the actual pediatric and/or hospital records-and often the parents have remembered things differently from the way they actually occurred. This is true of all parents, on all subjects, not just parents of children with autism. Memory is a reconstruction, not a photographic record.

Memory also works by establishing landmarks. Any parent who experiences the trauma of regressive autism will naturally, due to the very nature of memory, seek to associate that devastating event with another significant event, such as his child's bad reaction to a vaccination. This is the way our minds work.

In the wake of the controversy surrounding the publication the Wakefield report, researcher Eric Fombonne reviewed two large datasets. In the first, a review of the records of 174 French born between 1976 and 1985 showed no incidence of IBD. The second, a review of records of 2.1 million British children with autism spectrum disorder born in 1987 or later (and thus assumed to have been exposed to MMR vaccine), also showed no incidence of IBD.

In the May 2,1998 issue LANCET, Heikki Peltola, M.D. and colleagues described a 14-year prospective study between 1982 and 1996 in which the health of three million vaccinated children was followed. In a prospective study researchers do not have to rely upon inaccurate memories or potentially incomplete medical records; instead they track subjects from Day One. Of 3 million vaccines given, Peltola et at found only 31 cases of gastrointestinal symptoms, all of which were short-lived. Not one of these 31 children developed autism. Over a decade's effort to detect all severe adverse events associated with MMR vaccine could find no data

supporting the hypothesis that the MMR can cause either pervasive developmental disorder or inflammatory bowel disease.

Finally, critics of the Wakefield paper have pointed out that it is merely a collection of case reports, not an epidemiologic study attempting to determine whether this phenomena is real. A collection of reports can neither prove, nor disprove, hypothesis. To prove a connection between MMR vaccine, IBD and neurodevelopmental disability we need sound epidemiologic research, a research priority NAAR has been actively promoting. (See "Parent Groups Propose New Autism Research Legislation" on page 4.)

Could the MMR vaccine so overheat an already disordered immune system that it attacks the newly-vaccinated child's brain, leaving him or her with a lifelong disability? So far, given the vast amount of data on the safety and dangers of vaccine, the answer is no. Is an autoimmune-vaccine theory of autism plausible? Yes. Do the facts to date support the theory? No.

The fact that a hypothesis is plausible does not mean that it is true.

Where Do We Go From Here?

I am also asked, both as a doctor and as Vice President-Medical Affairs for NAAR, whether I have vaccinated my, own children. The answer is yes: both of our children received the full schedule of vaccinations, and if we were to have another child we would vaccinate him or her as well.

Nevertheless, at NAAR we are committed to investigating all possible causes of autism. As I noted above, the only way to resolve the issue of a connection between vaccination and autism is through rigorous epidemiological study of large populations of children. To that end, we have urged Congress to appropriate funds to undertake an epidemiologic study of the prevalence and causes of autism. This study could certainly, include data on the vaccination histories of children, as well as the vital issue of children's exposure to environmental toxins, medical disease, and a host of other issues. As a parent of a child with autism, I feel the same passion to push the science forward that drives us all. Let's direct that passion into productive channels and get the results that will finally give us the answers-and the help-we seek.

Bailey, A. et al (1998). A clinicopathological Study of Autism. Brain, 121: 889-905.

Bauman, Margaret and Kemper, Thomas. (1994). Neuroanatomic Observations of the Brain in Autism. The Neurobiology of Autism, 119-145.

Correspondence to the Lancet (1998): v. 351, no.9106; v. 351. no. 9112,v.352, bo. 9121;v. 352, no.9123.

Fombonne, Eric (1998). Inflammatory bowel disease and autism. Lancet, V-351, no.9101.

Pettola, H. et. al. (1997). No measles in Finland. Lancet, v. 350, no 9088.

Piven, J. et. al. (1990). Magnetic resonance imaging: evidence for a defect of cerebral cortical development in autism. American Journal of Psychiatry, 147 (6): 734-739.

Tuttle et. al. (1996). Update: Vaccine Side Effects, Adverse Reactions, Contraindications, and Precautions. Recommendations of the Advisory Committee on Immunization Practices.

Wakefield et. al. (1998). Ileal-Lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Lancet, 351:637-41.

Wentz, KR and Marcuse, EK. (I 99 1). Diptheria-Pertussis vaccine and serious neurologic illness.... Pediatrics, 87: 287-29-/.