Evidence supports it, so why are parents still reluctant to vaccinate their children?
Nearly 16 years after his controversial study was first published, the work of the discredited British doctor Andrew Wakefield - the researcher who linked the measles, mumps and rubella vaccine with autism - is back in the news.
Since 2010, Wakefield has been barred from practicing medicine in the UK. He now lives and works in the US where he retains a cult following.
Twitter comments involving one of Wakefield's most ardent supporters - the TV celebrity Jenny McCarthy, who wrote a foreword to his book Callous Disregard: Autism and Vaccines: The Truth Behind a Tragedy - have reignited the passionate debate over perceived links between vaccines and autism.
In addition, three new studies have found intriguing results on the support among the general public for the theory that vaccines cause adverse effects, particularly autism.
Fear of vaccines is not new and dates back to the invention of this medical procedure in the 17th century. As far back as 1802, vaccine inventor Dr. Edward Jenner was lampooned in the popular media of the time.
"The Cow Pock - or - the Wonderful Effects of the New Innoculation," a satirical painting by James Gillray that displayed commoners sprouting cows from their bodies having received a dose of Jenner's cowpox-derived smallpox vaccine, was emblematic of public fears over the nature of this new medical technology.
In recent times, major outbreaks of diseases previously thought to be under control in the US and UK due to vaccination - measles, mumps, and whooping cough - were assumed to be caused by a renewed fear of vaccination, possibly as a result of the combination measles, mumps and rubella (MMR) vaccine controversy.
Some people are also worried about potentially fatal outbreaks of other vaccine-preventable diseases, such as diphtheria and invasive Haemophilus influenzae, as immunization rates for these diseases have also fallen below federal guidelines.
MMR vaccine - the background
As far back as 1802, vaccine inventor Dr. Edward Jenner was lampooned in the popular media of the time.
The combination MMR vaccine was introduced in 1971, with a 96%, 95% and 94% effectiveness rate for measles, mumps and rubella, respectively.
In 1981, rates of measles in the US had dropped 80% from the following year thanks to widespread adoption of the vaccine. By 2000, endemic measles had been eliminated in the US, with only isolated cases appearing via travelers from foreign countries.
Although The Lancet had published Andrew Wakefield's study linking the MMR vaccine to autism in 1998, news of Wakefield's claims did not become popularized in the US until 2005, when an article written by political activist Robert F. Kennedy Jr. addressing fears that the thimerosal compound found in some vaccines causes autism was published in both Rolling Stone and Salon.
Robert F. Kennedy Jr. has contacted Medical News Today and taken the time to respond to some of the points expressed in this piece. We have published his letter in full, which can be accessed by following this link.
The interest in purported links between vaccines and autism was explosive. In 2007, Dan Olmsted founded The Age of Autism - the "Daily Web Newspaper of the Autism Epidemic" - which, boasting Jenny McCarthy among their prominent contributors, remains the touchstone of the anti-vaccination movement.
In 2008, an American outbreak of measles occurred. Of the affected patients, more than 90% had either not been vaccinated or had an unknown vaccination status.
Re-evaluation of Andrew Wakefield's evidence and methods
Brian Deer claimed that Wakefield had misrepresented clinical data on each of the 12 subjects in his 1998 study.
But while the anti-vaccination movement was gaining traction across the US during this period, the original research upon which the anti-vaccination campaigning was based was being seriously re-evaluated in the country from which it originated, the UK.
In particular, the BMJ - The Lancet's main competitor - ran a series of investigative articles by the journalist Brian Deer, examining not only Wakefield's initial research, but also his background as a physician.
Deer claimed that Wakefield had misrepresented clinical data on each of the 12 subjects in his 1998 study, and had also omitted health records showing that the children in the study had already presented with developmental delays symptomatic of autism before receiving the MMR shot.
Deer had also identified undisclosed conflicts of interest in the Wakefield case. Wakefield's attempt to discredit the MMR vaccine coincided with a move to patent his own rival vaccine and test kits, as part of a deal which some reports claim could have made him a millionaire.
BMJ's investigation culminated in a 2011 piece by editor-in-chief Fiona Godlee, denouncing Wakefield plainly as a "fraud." A 3-year inquiry by the British General Medical Council (GMC) into Wakefield and his MMR research had now found the doctor guilty of a vast number of professional misconduct charges. He was struck from the medical register and The Lancet officially retracted the 1998 study.
Continued support for 'MMR vaccine causes autism' theory
Speaking to Medical News Today, Brian Deer says of Wakefield:
"I don't believe he is convinced of the validity of his claims at all, and today he does not even seem clear about what they are. I think he is a sociopath who is incapable of comprehending, much less acknowledging, the nature of his misconduct. For more than a decade he has been wholly dependent for his livelihood on the parents of children with various kinds of disabilities and challenges. He has nowhere else to go but to do whatever it takes to ensure that they keep giving him money."
So why are Wakefield's theories still popular in the US? The Age of Autism's editor Dan Olmsted declined Medical News Today's invitation to comment on whether their organization's continued promotion of the now-discredited research has caused the anti-vaccination campaign to suffer credibility - "it's about how others perceive us and I'll leave that to them," is all he would offer.
A New York Times profile on Wakefield, and his new career of giving talks across the US on this theories, quoted one anti-vaccination campaigner: "To our community, Andrew Wakefield is Nelson Mandela and Jesus Christ rolled up into one," said JB Handley, founder of the Generation Rescue group. "He's a symbol of how all of us feel."
Perhaps the new studies into the psychology of vaccination fears may provide some clues to the continued support for Wakefield's consensus-questioning narrative.
Conspiracy theories 'reduce rates of vaccination'
"I've gotten heated responses from both sides," the University of Chicago's Prof. J. Eric Oliver told Medical News Today. "Some conspiracists are incensed that I suggest that people are drawn to conspiracy theories for psychological reasons rather than because they are the 'truth;' some on the other side are convinced that all conspiracy theorists are kooks."
Prof. Oliver's study into medical conspiracy theories suggests they have a perennial popularity because people often prefer the more straightforward narrative proffered by the conspiracy theory to science, which is cognitively challenging and carries a lot of uncertainty.
It is harder, he suggests, to understand epidemiology and probability theories, compared with the "if you put this substance in your body, it's going to be bad" rhetoric of conspiracy theorists.
When Medical News Today reported on Oliver's work recently, which suggested nearly half of Americans believe in medical conspiracy theories, many of our readers commented that some of the "conspiracy theories" tested in the study, such as whether US spy agencies deliberately infected black Americans with HIV, are not so inconceivable when you take into account previous unethical and racist medical experimentation such as "The Tuskegee Study of Untreated Syphilis in the Negro Male," where the US Public Health Service deliberately infected black men with syphilis under the guise of offering them free health care.
Additionally, Oliver's research revealed that 20% of the study participants believed the idea that childhood vaccines cause psychological disorders, such as autism.
"Yes, there have been numerous incidents of malfeasance of both over the years that are probably better publicized now than they were before the 1960s," Prof. Oliver admits.
"But I'm not sure that it's the greater publicity of these types of activities that motivates the adherence to conspiracy theories more than the fact that we now have more media outlets to promote the theories themselves. Most people don't fabricate conspiracy theories on their own - that's pretty cognitively demanding work; rather, people adopt conspiracy theories after they encounter them in public discourse."
Another study, published in PLOS ONE examined the effect of anti-vaccine conspiracy theories on vaccine intentions. The researchers from the University of Kent, UK, demonstrated that their group of 188 participants were much less likely to vaccinate after reading anti-vaccination conspiracy theories, and conclude that this is the cause of a current decline in UK vaccination rates.
They conclude that:
"This research is timely in the face of declining vaccination rates and recent outbreaks of vaccinated-against diseases in the UK, such as measles. Our studies demonstrate that anti-vaccine conspiracy theories may present a barrier to vaccine uptake, which may potentially have significant and detrimental consequences for children's health."
Pro-vaccine communications 'are ineffective'
A study in the journal Pediatrics assessed the effectiveness of vaccination messages. Political scientist Brendan Nyhan, PhD, tested four kinds of message on 1,759 Americans: "Autism correction" was a factual, scientific rebuttal of the claims that the MMR vaccine causes autism; "Disease risks" listed the risks of contracting measles, mumps or rubella; "Disease narrative" was a true story about a baby who contracted a very serious case of measles.
All of these vaccine promotions were based on the Centers for Disease Control and Prevention's (CDC) own messages.
The fourth type of message, "Disease images," was not based on CDC communications, but instead presented the subjects with distressing images of children infected with measles, mumps and rubella.
Dr. Nyhan found that "Disease images" and "Disease narrative" actually increased the the number of participants who believed that the MMR vaccine causes serious side effects - from 7.7% at the start of the study to 13.8% after being shown the messages.
The scientific correction of MMR-autism misinformation, "Autism correction," meanwhile, successfully reduced the number of respondents who believed the MMR vaccine causes autism. But there was an unexpected twist to this. Despite fewer people believing that the MMR vaccine causes autism, paradoxically, there was also a decrease in the number of parents in this group who were willing to vaccinate their children.
So, to reiterate, the one vaccination message that was successful at countering the effects of fear-propagating misinformation also somehow encouraged parents not to vaccinate their children. A similar "backfire" effect had also been recorded by Dr. Nyhan in a previous study on misinformation relating to the Iraq war.
"The recent research suggesting that lecturing parents, showing them cards, or presenting them with information in focus groups, is unsurprising," Brian Deer told us, adding:
"Whatever the safety profile of various vaccines may be, parents who choose to disregard medical advice are, in general, parents to whom it is important to believe that they are smarter than doctors. This is largely an issue of self perception, unrelated to any knowledge of vaccine efficacy or safety."
Despite this, Deer claims that his investigation on the MMR vaccine published in The Sunday Times reversed declining MMR vaccine acceptance levels in the UK and "was the major determinant in restoring rates to pre-Wakefield levels."
"This shows that the public is not oblivious to fact," he adds.
It seems that 4 years after Andrew Wakefield was barred by the GMC from practicing medicine, however, his controversial theories are as influential as ever.
Given the lack of efficacy of the CDC's pro-vaccination messages demonstrated by Brendan Nyhan in his study, an urgent reassessment of the psychology behind vaccine fears is needed in order to arm the public with the accurate medical information we all need to make informed choices about our health and the health of our loved ones.
Written by David McNamee
Copyright: Medical News Today
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