The most compelling accounts I've heard have suggested an interaction between thimerisol, aluminum, adjuvants, and the vaccine material in a small minority of genetically susceptible kids. Children who are immunologically compromised may respond in an atypical way to vaccinations. It's not just parents and cranks who entertain this possibility. Frontline could easily have found, e.g.:
[V]accine experts tend to look at the population as a whole, not at individual patients. And population studies are not granular enough to detect individual metabolic, genetic, or immunological variation that might make some children under certain circumstances susceptible to neurological complications after vaccination. . . . The debate roils oneven about research. The Institute of Medicine in its last report on vaccines and autism in 2004 said that more research on the vaccine question is counterproductive: Finding a susceptibility to this risk in some infants would call into question the universal vaccination strategy that is a bedrock of immunization programs and could lead to widespread rejection of vaccines. The IOM concluded that efforts to find a link between vaccines and autism 'must be balanced against the broader benefit of the current vaccine program for all children.' " -- Dr. Bernardine Healy, former director of the American Red Cross and the US National Institutes of Health.
Here she is on CBS
Or,
this statement from an autism research center at UC Davis.
We're not talking about the majority of kids by any stretch, but we don't know what the markers are. I've seen suggestive research on certain genetic markers, but nothing remotely conclusive. I'm not sure how to compare the stress on a developing infant's immune system from a common cold to a series of vaccines with adjuvants and other vaccine components that are injected in rapid succession. The whole point of adjuvants is to intensify the immune response, no? What are the concentrations of biological agents injected in vaccination? Does that not matter? I'm asking honestly. I tend to share Joe's skepticism about the antigen overload argument, too. Perhaps there is an different trigger altogether. Still, it seems to me that scientists ought to at least entertain the possibility that vaccines play some role, given that the US requires twice as many vaccinations for kids under five than the average for the developed world. To my knowledge, the potential synergistic effect of grouping vaccinations together has never been studied; the CDC in particular has tried to shut down debate and keep people from asking questions on the basis of deeply flawed science -- admittedly, published by well-credentialed scientists in prestigious venues.
Madsen's ubiquitous 2003 study that purported to show that autism rates continued to rise after thimerisol was removed -- that was the one Frontline presented as proof positive that mercury is not involved at all, case closed -- admits that the way they collected data changed a critical juncture in the study. Just as they show rates going up, in 1995, Madsen's team added outpatient clinics to their count of autism cases. That's where almost 95 percent of Danish kids got diagnosed. Those cases were left out before 1995:
"The increase in the incidence of autism
from 1990 on may be attributable to more attention
being drawn to the syndrome of autism and to a
change in the diagnostic criteria from the ICD-8 to
the ICD-10 in 1994. Also, outpatient activities were
included in the Danish Psychiatric Central Research
Register in 1995 and because many patients with
autism in former years have been treated as outpatients
this may exaggerate the incidence rates, simply
because a number of patients attending the child
psychiatric treatment system before 1995 were recorded
for the first time, and thereby counted as new
cases in the incidence rates." -- Madsen et al., "Thimerosal and the occurrence of autism: negative ecological evidence from Danish population-based data," Pediatrics (Sept. 2003)
Maybe I'm too cynical, but this work was paid for largely by Denmarks largest vaccine manufacturer, Statens Serum Institute. Although the article does not disclose it, I gather it was initiated by the CDC.