The perpetrator of the autism-MMR myth, Andrew Wakefield, along with two of his collaborators, was found by Britain's General Medical Council (GMC) to have engaged in misconduct in relation to sparking this controversy (see Brian Deer's story in The Sunday Times for more information; http://www.timesonline.co.uk/tol/news/uk/health/article7009882.ece). Likely sensing he would be unfavorably judged, Wakefield didn't bother to show for the verdict. Among the dozens of charges the GMC deemed proven against Wakefield are that he provided a research proposal to a lawyer seeking to sue vaccine manufacturers for causing autism. This study, if it found that the measles-mumps-rubella (MMR) vaccine could cause autism in children, would greatly assist the lawyer in supporting his argument. With financial backing from a source that represented the ultimate conflict of interest, the study was carried out. Wakefield had previously conducted research that potentially implicated that the MMR was a causal factor in Crohn's disease but this research was not validated. This new take on the "dangers" of MMR proved to be financially lucrative for Wakefield but may eventually lead to his losing his medical license later this year when the GMC decides on what sanction should follow from this misconduct.
As Wakfield's hypothesis suggests, the measles-mumps-rubella (MMR) vaccine causes irritable bowel-like gut problems which leads to developmental regression that manifests as autism. ASDs clearly have a genetic origin but one of the environmental triggers that have been identified is rubella. If a pregnant mother contracts rubella, there is an increased chance of the child having an ASD (Chess et al., 1971/74/77). As the MMR vaccine decreases the chance of rubella infections, its use should decrease the likelihood of this environmental triggering of autism. However, the Wakefield hypothesis posits that the MMR vaccine triggers regression that is sometimes part of the course autism (i.e., some children with ASDs lose skills that they previously acquired in early development). Wakefield suggested that measles was a cause because he and his colleagues purportedly detected components of the measles virus in the gastrointestinal tracts and blood of children with autism that were not present in typically developing children.
Regardless of Wakefield's unethical conduct, is there evidence that supports this hypothesis? A study published in Pediatrics attempted to determine whether measles was more likely to found in the bodies of children with ASDs than in typically developing children. D'Souza and colleagues (2006) collected the largest sample of subjects for this type of study and used the same technique, polymerase chain reaction assays, that had purportedly detected measles in children with ASDs. They found that this technique produced many positive reactions in both children with ASDs and typical children. However, these reactions were further analyzed and found to be false positives for all subjects. The products of the reactions were cloned and genetically sequenced and none of these sequences contained the components of the measles virus. That is, neither the children with ASDs nor the typical children showed any evidence of measles virus in their bodies. Furthermore, there were no differences found in anti-measles antibodies across the study groups of children.
This, taken in combination with numerous other studies showing no relation between the MMR vaccine and ASDs, provides fairly definitive evidence against the "MMR causes autism" hypothesis. Wakefield was found by Brian Deer to have been paid a great deal by this group seeking to pursue litigation against vaccine manufacturers in the United Kingdom. Once this severe conflict of interest was revealed in The Sunday Times, ten of Wakefield's co-authors requested that their names be withdrawn from the original publication in the journal Lancet used as support for this hypothesis. More information on the Wakefield scandal can be found at http://briandeer.com/, a website maintained by the investigative journalist who revealed the conflict of interest (and who also has broken stories that have been damning to pharmaceutical companies).
But where does this leave us today? We clearly have seen a drop in the uptake of the MMR vaccine in a number of places, no more so than in Britain where a boy died of the disease and the number of cases of measles has skyrocketed for a disease that had been nearly eradicated. Furthermore, the resources that have been spent pursuing this fruitless avenue are immense. The costs are great and will continue, as the public's confidence in vaccination has been significantly damaged by this controversy. The evidence of harm following from Wakefield's misconduct is great but even if he loses his medical license it is likely that he will continue to benefit. Many view him as a hero taking on the mainstream rather than seeing him as the sloppy, ethically challenged researcher that the GMC has ruled him to be.
D'Souza et al., (2006). No Evidence of Persisting Measles Virus in Peripheral Blood Mononuclear Cells From Children With Autism Spectrum Disorder. Pediatrics, 118, 1744-1745.