WARNING: This article refers to dangerous misinformation.
It’s 6 o’clock on a wintry Melbourne evening and I’ve just received the venue address for a “secret screening” of the anti-vaccination film Vaxxed. I walk into a long, narrow room in Hawthorn Arts Centre with a table of books at the back. One children’s book, Melanie’s Marvelous Measles, tells of a girl who isn’t vaccinated but avoids the disease because she eats lots of raw food and boosts her immune system with positive thoughts.
I don’t have kids, and I’m here purely out of curiosity. In the morning’s press, a doctor described it as one of the most dangerous films he’d ever come across. In the month that followed, health ministers would slam it in the media, one of the film’s producers would be banned from the country, and a complementary medicine GP who attended this screening would be under investigation for helping anti-jab parents avoid vaccinations. How could a 90-minute movie be such a threat to public health?
It’s not what I expect. The film centres on accusations of scientific fraud at the United States Centres for Disease Control and Prevention (CDC), alleging a cover-up over a link between measles, mumps, rubella (MMR) vaccine and autism. This conspiracy theory is juxtaposed with heart-wrenching footage of severely autistic children struggling to speak. We see grainy home video of injured, wailing babies. “Jesus,” whispers a man in front of me. I came here highly sceptical, but still I scribble in my notebook: What if it’s true? Those poor kids.
Later, I feel duped. Here’s what I should have known beforehand.
The film is directed by and stars Andrew Wakefield. Anyone previously exposed to this issue will groan at the name, and perhaps wonder how I could have been so ignorant, but childhood vaccination isn’t a topic that comes up very often if you don’t have kids. Plus there’s a whole new generation of parents out there who might not know the history, so it’s worth recounting.
In 1998, medical journal The Lancet published a paper by Wakefield and others proposing a link between MMR vaccine and autism. Although it was based on just 12 children, at a press conference Wakefield called the safety of the MMR vaccine into question, sparking a public health crisis. As the vaccination rate dropped, measles re-emerged in England.
It was later revealed Wakefield had received hundreds of thousands of dollars as a consultant to lawyers representing parents wanting to sue over the MMR vaccine. His data was falsified, and the British General Medical Council found Wakefield guilty of both misconduct and a failure to disclose conflicts of interest. He was branded “dishonest” and lost his licence to practise medicine. His original paper has now been retracted.
Meanwhile, scientists had been investigating his theory in Poland, Britain, the US, Japan and Denmark. None, including a Danish study of data from 537,303 children, found an association between MMR vaccine and autism. A 2012 review from the US Institute of Medicine (now the National Academy of Medicine) concluded: “The evidence favors rejection of a causal relationship between MMR vaccine and autism.”
“An enormous amount was spent trying to see if the claims in the Wakefield paper were true,” says Nobel prize-winning immunologist Professor Peter Doherty of the University of Melbourne. “It was looked at very thoroughly and no evidence was found to support it.”
Watching the film again after reading the literature, I find it incredibly misleading. It tries to discredit a single study from 2004, as if that were of pivotal importance, when in fact there’s a mountain of evidence against Wakefield’s theory. In the film, Wakefield is a reasonable-sounding doctor with a plummy British accent. In reality, he’s the author of a damaging fraud who is now preying on parents’ fears.
So why does the myth persist? Partly it’s the work of radical fringe groups manufacturing the appearance of a controversy, and people new to the topic, like me, who get sucked in. Media coverage can also fuel the myth and a few leading experts refused to comment for this reason.
Yet with the rise of social media, conspiracy theories can thrive in clusters of like-minded people on the internet. “I definitely agree they don’t need to be given coverage, but at the same time you can’t not address it,” says Dr Sue Rodger-Withers, a virologist who lives in the Northern Rivers region of New South Wales, an area with one of the lowest vaccination rates in Australia.
But actually, parents who refuse to vaccinate their children are a tiny minority. Most Australian children – about 93 per cent by age five – are fully vaccinated. Even during the Wakefield scare in Britain, Australia’s national MMR vaccination rate remained relatively stable.
However, some concerns about vaccination will probably always exist because they arise from a fundamental flaw in human thinking. The Science of Immunisation, a booklet from the Australian Academy of Science, explains that “some adverse events coincide with, but are not caused by, vaccination”.
The clinical signs of autism, for example, commonly occur in the second year of life, coinciding with the time when the MMR vaccine is given. “It appears to the parent that somehow the vaccination is responsible, particularly when you’ve got this climate [of controversy] out there,” explains Doherty. “That’s the problem – it’s a false correlation.”
The film exploits this all-too-human error, combining footage of suffering autistic kids with narrative about the MMR vaccine. In a heightened emotional state – those poor kids – I associated one with the other, even if the rational side of me wasn’t convinced.
Later, I showed the film to cognitive psychologist Stephan Lewandowsky of the University of Bristol, a global expert on misinformation. “People link two distinctive events, and the moment you have that linkage, it becomes difficult for that to ever be disconfirmed,” he says.
But pointing this out can come across as patronising. “You’re running the risk of hurting their feelings if you’re trying to correct that belief.”
Lewandowsky has conducted extensive reviews of the literature on why myths are so hard to correct. “Even putting aside all the emotion and politics and specific issues that people might feel strongly about, we know that processing a negative or a correction is difficult for simple cognitive reasons.”
In one well-known 1994 study about a fictitious warehouse fire, people were first told flammable substances were left in a closet, implying the business owners were negligent. They were then told that was false and the closet was actually empty. Despite understanding and accepting the correction, people still attributed negligence to the owners, based on the misinformation they knew to be wrong.
A follow-up experiment found that unless people were given another cause to explain the fire, they stuck with the original false version. “People prefer an incorrect model over an incomplete model,” writes Lewandowsky and another researcher, John Cook, in a guide to debunking myths. “In the absence of a better explanation, they opt for the wrong explanation.”
The problem with the MMR vaccine myth is there isn’t an easy alternative explanation for what causes autism. Scientists have identified genetic factors, environmental and biological influences and shifting diagnostic criteria as reasons for the increased number of cases, but no single cause can fill the cognitive gap left behind by debunking. The truth isn’t so seductively simple.
Worse, efforts to correct the myth can backfire. In a 2014 study, American parents were shown information debunking the link between MMR vaccine and autism. While this corrected the misperception, it also made parents who weren’t favourable to vaccines in the first place even less likely to vaccinate a future child. Other messages – such as a dramatic narrative about an infant who almost died from measles, and graphic images of sick children with spots from the disease – also didn’t work.
But there are a few ways forward – and one of them is inspired by the theory of vaccination itself. In the same way vaccines generate antibodies to resist viruses, psychologists are hoping to “inoculate” the public with counterarguments that will boost their immunity to bogus claims.
This year, two British researchers published a paper that used this inoculation technique to counter anti-vaccine conspiracy theories. People who were given the facts first were resistant to anti-vaccine conspiracy theories and were more likely to decide to vaccinate a hypothetical child. Lewandowsky has co-written a paper showing that inoculation messages can neutralise climate change misinformation too.
One of Lewandowsky’s recommendations is to include an explicit warning at the beginning – just like at the top of this article. While writing about a myth risks reinforcing it, exposing a little bit of anti-vaccination propaganda could help people build up intellectual antibodies, too.
This article was first published in the print edition of The Saturday Paper on Sep 2, 2017 as "League of vaccinations". Subscribe here.
Autism rates in developing countries have risen remarkably in the past 20 years. For children born in 1992, according to the U.S. CDC, about 1 in 150 would be diagnosed with an autism spectrum disorder (ASD). For children born in 2004, about 1 in 68 children would receive an ASD diagnosis. It is difficult to compare autism rates from the 1990s and later with rates from the 1940s through the 1980s: in earlier years, autism was associated primarily with very severely affected individuals and the rate of autism was estimated to be only about 1 in 10,000 people. Beginning in the 1990s, our understanding of the spectrum of autism has expanded greatly, and now individuals who would most likely previously not have been thought of as having autism may be classified with one of a variety of ASDs.
Whether the high rates of autism today are due to increased diagnosis and reporting, changing definitions of autism, or an actual increase in development of ASD is unknown., Regardless, researchers and worried parents alike have speculated about causes of autism, and the issue has been widely studied. The role of vaccines has been questioned, along with other possible risk factors for ASD, such as genetic predisposition, advanced parental age, and other environmental factors. Vaccines have perhaps received more scrutiny that any other speculated cause of ASD, and the great majority of scientists, physicians, and public health researchers have come to the conclusion that there is no association between vaccines and autism. Some, however, still question whether vaccines play a role in ASD development, and so the public health and medical establishments continue to address these concerns.
The MMR Hypothesis
The story of how vaccines came to be questioned as a cause of autism dates back to the 1990s. In 1995, a group of British researchers published a cohort study in the Lancet showing that individuals who had been vaccinated with the measles-mumps-rubella vaccine (MMR) were more likely to have bowel disease than individuals who had not received MMR. One of these researchers was gastroenterologist Andrew Wakefield, MD, who went on to further study a possible link between the vaccine and bowel disease by speculating that persistent infection with vaccine virus caused disruption of the intestinal tissue that in turn led to bowel disease and neuropsychiatric disease (specifically, autism). Part of this hypothesis – that vaccination was associated with autism – had been suggested previously a few researchers. For example, Fudenberg, in a small pilot study published in a non-mainstream journal, posited this relationship, as did Gupta in a review of possible treatments for autism. This hypothesis had not been systematically investigated when Wakefield began to interrogate it.
In 1998, Wakefield, along with 12 co-authors, published a case series study in the Lancet claiming that they found evidence, in many of the 12 cases they studied, of measles virus in the digestive systems of children who had exhibited autism symptoms after MMR vaccination. Though in the paper they stated that they could not demonstrate a causal relationship between MMR vaccination and autism, Wakefield suggested in a video released to coincide with the paper’s publication that a causal relationship existed between the MMR and autism: “…the risk of this particular syndrome [what Wakefield termed autistic enterocolitis] developing is related to the combined vaccine, the MMR, rather than the single vaccines.” He then recommended that the combination MMR vaccine be suspended in favor of single-antigen vaccinations given separately over time. (Wakefield himself had filed for a patent for a single-antigen measles vaccine in 1997 and so would seem to have a potential financial interest in promoting this view.)
Reaction to the Wakefield publication was immediate. Press outlets covered the news widely and frightened parents began to delay or completely refuse vaccination for their children, both in Britain and the United States. MMR vaccination rates in Britain plummeted.
Over the next twelve years, the possibility of a link between MMR and autism was studied exhaustively. No reputable, relevant study confirmed Wakefield’s findings; instead, many well-designed studies have found no link between MMR and bowel disease or MMR and autism.,
In 2004, then-editor Dr. Richard Horton of the Lancet wrote that Wakefield should had revealed to the journal that he had been paid by attorneys seeking to file lawsuits against vaccine manufacturers. In television interviews, Horton claimed that Wakefield’s research was “fatally flawed.” Most of the co-authors of the study retracted the interpretation in the paper, and in 2010, The Lancet formally retracted the paper itself.
Three months after the retraction, in May 2010, Britain’s General Medical Council banned Wakefield from practicing medicine in Britain, stating that he had shown “callous disregard” for children in the course of his research. The council also cited previously uncovered information about the extent to which Wakefield’s research was funded by lawyers hoping to sue vaccine manufacturers on behalf of parents of children with autism.
On January 6, 2011, the BMJ published a report by Brian Deer, a British journalist who had previously reported on flaws in Wakefield’s work. For this new report, Deer spoke with parents of children from the retracted study and found evidence that Wakefield committed research fraud by falsifying data about the children’s conditions.
Specifically, Deer reported that while the paper claimed that eight of the study’s twelve children showed either gastrointestinal or autism-like symptoms days after vaccination, records instead show that at most two children experienced these symptoms in this time frame. Additionally, while the paper claimed that all twelve of the children were “previously normal” before vaccination with MMR, at least two had developmental delays that were noted in their records before the vaccination took place.
After examining the records for all twelve children, Deer noted that the statements made in the paper did not match numbers from the records in any category: the children having regressive autism; those with non-specific colitis; or those showing first symptoms within days after receiving the MMR vaccine. The Lancet paper claimed that six of the children had all three of these conditions; according to the records, not a single child actually did. (See a table entitled “Comparison of three features of the 12 children in The Lancet paper with features apparent in the NHS records, including those from the Royal Free hospital” that breaks down the comparison between the Lancet numbers and the medical records in the Deer article here.)
In an accompanying editorial, BMJ editor in chief Fiona Godlee and co-authors Jane Smith and Harvey Marcovitch examine the damage to public health caused by a tiny study based on parental recall with no control group – a study that turned out to be almost entirely fraudulent, but whose impact continues to this day.
Although the findings of Wakefield’s paper have long been discredited by scientists, the evidence that the data itself was falsified makes this report by the BMJ a landmark moment in the history of vaccines. Evidence is strong that the original study should not have been published not merely because it was poorly conducted, but also because it was a product of research fraud.
The Thimerosal Hypothesis
MMR is not the only vaccine or vaccine component that has been targeted for scrutiny by those who suspect vaccination might be related to autism. After the MMR controversy died down, critics turned their questions to thimerosal, a mercury-containing preservative used in some vaccines. (Thimerosal had never been used in MMR, as antimicrobial agents are not used in live vaccines.)
In the late 1990s lawmakers, environmentalists, and medical and public health workers became concerned about environmental exposures to mercury, particularly from consumption of fish. With heightened attention to known and potential harmful effects of such exposures, the U.S. Food and Drug Administration (FDA) in 1999 requested that drug companies report on amounts of mercury in their products. The results for mercury in vaccines, in the form of thimerosal, exceeded FDA guidelines for exposures to the kind of mercury found in fish. Mercury in fish appears in the form of methylmercury, which is not readily metabolized and excreted in the human body. It is known to cause, at certain levels of high exposure, harmful neurological effects. The mercury in thimerosal metabolizes in the body to ethylmercury, a compound that, while not widely studied at the time, was thought to be much less harmful than methylmercury.
The FDA had a dilemma: there were no recommendations for exposure to levels of ethylmercury. Should they apply the methylmercury guidelines to ethylmercury? Was there cause for concern about exposure to mercury in childhood vaccines? Unable to answer these questions immediately, together with the American Academy of Pediatrics and other groups, they called for vaccine companies to reduce or eliminate the use of thimerosal in vaccines. Additionally, studies were planned to investigate whether there were harmful effects in children exposed to the amount of mercury in vaccines.
Activists and others became concerned about the safety of thimerosal at this point, and they posited that autism could be an outcome of exposure to mercury in vaccines. The Institute of Medicine undertook a comprehensive safety review of the issue. Their preliminary report, published in 2001, stated that the committee did not find enough evidence to support or reject a causal relationship between mercury in vaccines and neurodevelopmental disorders. However, their final report, published in 2004, came to the conclusion that the large body of evidence gathered on the question since 2001 favored rejecting the hypothesis that mercury in vaccines was associated with neurodevelopmental disorders. Since then, evidence from many studies has continued to support rejecting an association between thimerosal and autism., 
Today, thimerosal is no longer used in most childhood vaccines, though some forms of influenza vaccine available in multi-dose vials may contain the preservative.
After thimerosal was removed from most vaccines, autism rates did not drop. Rather, they continued to rise. Some vaccine critics shifted their attention from a hypothesized mercury exposure/autism connection to other targets. One such target is the number of vaccines given to children. Many vaccines have been added to the childhood immunization schedule since the 1980s, and some critics have voiced concern that this increase in vaccine exposure results in autism. However, no evidence of an association between increased exposure to vaccines and autism has appeared. Others have focused on the aluminum adjuvant in some vaccines as a potential cause of autism. Yet the amounts of aluminum used in vaccines are small in comparison to other exposures to aluminum, such as in breast milk and infant formula. Aluminum in vaccines has not been implicated in any infant or childhood health problems.
Most scientific and medical experts are satisfied that no connection exists between vaccines and autism and other neurodevelopmental disorders. Still, critics continue to question the issue. Not only do they question the relationship between MMR and thimerosal and autism, they bring up further culprits they believe might play a role in development of autism. Researchers continue to examine these questions, but there is no evidence that these factors play a role in autism development. Most autism researchers hold that the causes of autism are many and include genetic and environmental factors, but do not involve vaccines.,
- Centers for Disease Control and Prevention. Autism Spectrum Disorder: Data & Statistics. Accessed 01/25/2018.
- Rice, C.E., Rosanoff, M., Dawson, G., Durkin, M., Croen, L.A., Singer, A., Yeargin-Allsopp, M. Evaluating changes in the prevalence of the autism spectrum disorders (ASDs).Public Health Reviews. 2012; 34(2): 1.
- Hertz-Picciotto, I., Delwiche, L. The rise in autism and the role of age at diagnosis. Epidemiology. 2009; 20(1): 84.
- CDC. Autism spectrum disorder (ASD). Research. Accessed 01/25/2018.
- National Institutes of Health. National Institute of Neurological Disorders and Stroke. Autism spectrum disorder fact sheet. Accessed 01/25/2018.
- Immunization Safety Review Committee, Institute of Medicine. Immunization safety review: vaccines and autism. National Academies Press, 2004. Accessed 01/25/2018.
- Thompson, N.P., Pounder, R.E., Wakefield, A.J., & Montgomery, S.M. Is measles vaccination a risk factor for inflammatory bowel disease? The Lancet. 1995; 345(8957): 1071-1074.
- Fudenberg, H.H. Dialysable lymphocyte extract (DLyE) in infantile onset autism: a pilot study. Biotherapy. 1996; 9(1-3): 143-147.
- Gupta, S. Immunology and immunologic treatment of autism. Proc Natl Autism Assn Chicago.1996;455–460
- Wakefield A, et al. RETRACTED:—Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Lancet. 1998; 351(9103): 637-641.
- Deer, B. Royal free facilitates attack on MMR in medical school single shots videotape. No date. Accessed 01/25/2018.
- Deer, B. Revealed: Wakefield’s secret first MMR patent claims “safer measles vaccine.” No date. Accessed 01/25/2018.
- Offit, P.A. Autism’s False Profits. New York: Columbia University Press; 2008. See Chapters 2 and 3.
- See a list of such studies in this Children’s Hospital of Philadelphia Vaccine Education Center document.
- Horton, R. A statement by the editors of The Lancet. The Lancet. 2004; 363(9411): 820-821.
- Laurance, J. How was the MMR scare sustained for so long when the evidence showed that it was unfounded? The Independent. September 19, 2004. Accessed 01/25/2018.
- Murch, S.H., Anthony, A., Casson, D.H., Malik, M., Berelowitz, M., Dhillon, A.P., ... Walker-Smith, J.A. Retraction of an interpretation. Lancet. 2004; 363(9411): 750.
- The Editors of The Lancet. Comment: RETRACTION:—Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. The Lancet. 2010; 375(9713): 445. Accessed 01/25/2018.
- Meikle, J., Boseley, S. MMR row doctor Andrew Wakefield struck off register. May 24, 2010. Accessed 01/25/2018.
- Deer, B. How the case against the MMR vaccine was fixed. BMJ. 2011; 342: c5347. Accessed 01/25/2018.
- Godlee, F., Smith, J., Marcovitch, H. Wakefield’s article linking MMR vaccine and autism was fraudulent. BMJ. 2011; 342: c7452. Accessed 01/25/2018.
- World Health Organization. Thimerosal in vaccines. July 2006. Accessed 01/25/2018.
- Most of this narrative refers to the facts and chronology outlined in the Food and Drug Administration’s Publication Thimerosal in Vaccines.
- Immunization Safety Review Committee, Institute of Medicine. (2001). Immunization safety review: measles-mumps-rubella vaccine and autism. National Academies Press. Accessed 01/25/2018.
- CDC. Science summary: CDC studies on vaccines and autism. Accessed 01/25/2018.
- American Academy of Pediatrics. Vaccine safety: examine the evidence. (122KB). Updated April 2013. Accessed 01/25/2018.
- DeStefano, F., Price, C.S., Weintraub, E.S. Increasing exposure to antibody-stimulating proteins and polysaccharides in vaccines is not associated with risk of autism. The Journal of Pediatrics. 2013; 163(2): 561-567.
- Children’s Hospital of Philadelphia. Vaccine Education Center. Vaccines ingredients: Aluminum. Accessed 01/25/2018.
- CDC. Autism spectrum disorder (ASD). Research. Accessed 01/25/2018.
- National Institutes of Health. National Institute of Neurological Disorders and Stroke. Autism spectrum disorder fact sheet. Accessed 01/25/2018.
Last update 25 January 2018