As I blogged abut last week (http://www.psychologytoday.com/blog/radical-behaviorist/201001/di...), one of the studies touted as evidence that vaccines cause autism was brought into question by the General Medical Council's (GMC) ruling that Andrew Wakefield had acted dishonestly and without the approval of an ethics committee. Subsequent to my post The Lancet officially retracted the study, largely as a result of GMC's findings. In this post, I'd like to tackle some of the issues surrounding the media's coverage of this topic.
A close reading of the published article may suggest that regressive autism and severe bowel problems could possibly be associated with the measles-mumps-rubella (MMR) vaccine but it was explicitly stated that this study did not establish a causal association between these variable (Wakefield et al., 1998). It is likely that peer review required the authors to state that their study did not prove a link between MMR and autism. However, after the study was published, Wakefield reported to the media that his work strongly suggested that there was a causal link between MMR and autism. The press conference was televised and many media outlets uncritically presented Wakefield's proclamation despite the fact that his published research contradicted his words. Wakefield has held press conferences since then to present unpublished research, and to claim that the UK released the MMR vaccine without properly testing it.
This set in motion a rapid decrease in the vaccination of children against these diseases that was reversed as the result of Brian Deer's investigative journalism that revealed Wakefield had been paid a large sum of money by a group seeking to sue vaccine manufacturers before conducting his research (for full details on this scandal go to; http://briandeer.com/mmr-lancet.htm). Clearly, the media can serve to protect the public interest but more often than not they fail to do so.
Brent Taylor and colleagues reported an interesting and unsettling finding related to the impact of the MMR controversy. In Taylor et al. (2002), multiple parental interviews were obtained for many children diagnosed with an ASD about when they noticed the onset of autistic symptoms. A review of each individual case was made. It was found that several parents reported different times of the onset of autistic symptoms in different interviews. "A review of each record showed that in 13 children the history given by the parents had changed after the extensive publicity about MMR vaccine and autism. Before the publicity the parents often reported concerns early in their child's life, usually before their first birthday; the current history for the same children recorded symptoms as developing only after MMR vaccination, in some cases shortly after. This bias associated with changes in the history given by the parents necessitates particular care when interpreting [parental report]" (Taylor et al., 2002).
Andrews et al. (2002) found that parents of children with autism diagnosed after the MMR controversy was publicized in the media were more likely to report the onset of autism as just after MMR vaccination than were parents of children with autism diagnosed before the controversy. The impact of the media's coverage of this issue has had a significant and detrimental influence. Unfortunately, highly improbable events, extraordinary claims implying a conspiracy, and steadfast beliefs with little support beyond anecdote tend to given more coverage than sound information based upon empirically valid and peer reviewed research.
Another typical tactic of the media is to present controversial topics as if there are two, equally relevant sides to the story. I encountered one example in yesterday's Boston Herald (http://bostonherald.com/news/regional/view.bg?articleid=1231165). The story includes the following quotes:
"I am absolutely certain that environmental factors are 100 percent responsible for the rise in the autism rate. Mercury and vaccines are among the primary suspects," said Cambridge resident Mark Blaxill, director of SafeMinds, a leading nonprofit founded to investigate and publicize claims that mercury in medical products poses risks to kids... "Andy is a fine man and a terrific scientist," said Blaxill, whose daughter has autism. "This is nothing more than a very well organized and systematic effort to intimidate and suppress the science."
In a statement about the retraction, the CDC cited an "overwhelming body of research by the world's leading scientists that concludes there is no link between MMR vaccine and autism."
The reporter who wrote this story is following a well worn path tread by many media outlets. The coverage of this story on CNN also demonstrates the point/counter-point style. Though it is preferable to referring to Wakefield as this generation's Galileo, it is not thorough coverage of the story (see Brian Deer's work as a refreshing example of thorough coverage). Just a little searching of medical journals and public records would reveal compelling evidence that there is no credibility to the Wakefield MMR myth.
Research conducted by Brent Taylor at The Royal Free and University College Medical School, where Wakefield and colleagues conducted their work, contradicts the assertion made by Wakefield that the MMR was associated with a higher probability of gastrointestinal problems (Taylor, Miller, Lingam, Andrews, Simmons, & Stowe, 2002). They reviewed the medical records of over 400 persons with autism and found that there was no increased prevalence of bowels problem or regression following the introduction of the MMR vaccine in London in 1979.
In my post linked to above, I discussed research showing that measles was not more likely to be found in the bodies of children with ASDs than in typically developing children. There was also the testimony in the Autism Omnibus proceeding of the world's foremost authority on the research method used in the Wakefield study, Stephen Bustin. He described how the Wakefield results were the product of contamination (transcripts from the Autism Omnibus proceeding can be accessed here; http://neurodiversity.com/weblog/article/189/). There should have been measles RNA in the samples but there was only DNA. So, the Wakefield results were, in fact, not positive for measles from the MMR vaccine they were positive for measles introduced into the lab by the investigators. This was confirmed in the Autism Omnibus proceedings by the testimony of Nicholas Chadwick who worked in Wakefield's lab. He stated that they found no positive results for the measles virus found in the MMR during the study and that he informed Wakefield of this.
This, in combination with numerous other studies showing no relation between the MMR vaccine and ASDs (e.g., Dales, Hammer, & Smith, 2001; Fombonne & Chakrabarti, 2001; Kaye, del Mare Melero-Montes, & Jick, 2001; Honda, Shimzu, & Rutter, 2005; Mrozek-Budzyn, Kieltyka, & Majewska, 2009), provides fairly definitive evidence against the "MMR causes autism" hypothesis. Not doing the investigative end of journalism is lazy and the results of sloppy reporting that then appears in the media is just as culpable as those intentionally propagating the vaccines cause autism myth.
Andrews, N., Miller, E., Taylor, B., Lingam, R., Simmons, A., Stowe, J., & Waight, P. (2002). Recall bias, MMR, and autism. Archives of Disabled Children, 87, 493-