I’ve been catching up with my reading. I think some of what I’ve been catching up on is worth sharing. The journal Vaccine had a special edition in 2012 on The Role of Internet Use in Vaccination Decisions. Of the articles, three stood out for me. One on the nature of online discussion and participants, another on provision of information by the media, and one on tactics and tropes of the anti-vaccine movement.
Evidence shows that individuals turn to the Internet for vaccination advice, and suggests such sources can impact vaccination decisions – therefore it is likely that anti-vaccine websites can influence whether people vaccinate themselves or their children. This overview examines the types of rhetoric individuals may encounter online in order to better understand why the anti-vaccination movement can be convincing, despite lacking scientific support for their claims. [My emphasis.]
This is how, despite lacking evidence, anti-vaccine websites can persuade the undecided:
- skewing science
- shifting hypotheses
- censoring dissent
- attacking critics
On skewing science, the author reports that science is praised when (but only when) scientific evidence appears to support an anti-vaccine position and gives as one example of this a website that ranks scientific papers on vaccination. The rankings are biased against studies conducted or funded by the CDC and towards studies conducted by people like Mark Geier. The anti-vaccine movement demands more research, but rubbishes the available well-conducted research because the results do not support the anti-vaccine arguments.
When it comes to shifting hypotheses, this is something so noticeable that a paper was actually published on the phenomenon. Gerber and Offit addressed three of the hypotheses proposed by the anti-vaccine movement regarding vaccines and autism. In each case there was a lack of biological plausibility and a lack of evidence for the anti-vaccine movement’s claim. Despite this, research was conducted to investigate each of the claims and each time a claim was shown to be untrue the anti-vaccine movement simply shifted the goalposts. In one case, the research was conducted after Gerber and Offit’s paper (which argued that the notion that vaccines cause autism had been effectively dismissed and further studies on the cause or causes of autism should focus on more-promising leads). Four years after Gerber and Offit, researchers published a paper that contradicted the third of the three claims.
There will probably be some people who have been banned from anti-vaccine websites and forums (as with any other website that has a comment facility) for making defamatory accusations, posting abuse, or some other infraction that actually warranted the wielding of the banhammer. However, there will also be many people who have been banned from anti-vaccine websites or forums simply for posting reasonable, evidence-based comments that happen to be critical of anti-vaccine canards. As Kata points out, such websites may act as “echo chambers”, where one point of view is unquestioningly repeated and reinforced while critiques are expunged. If the censor is efficient it might be that nobody will know that you’ve been banned, let alone why. Anti-vaccine websites disingenuously refer to censorship of dissent as “comment moderation” or creating a “safe environment” and sometimes pretend (when they do admit to banning critics) that the people banned for disagreeing with them were trolling or being abusive.
There may be some anti-vaccine websites that attack critics by pointing out factual errors or flaws in their logic (I can’t recall any off-hand but I wouldn’t want to rule out the possibility). From what I have seen, attacks on critics of the anti-vaccine movement have included false accusations of various things from dishonesty to parent bashing to the tediously ubiquitous pharma shill accusation. There’s also, as Kata points out, legal chill from the vexatious use of libel law. Or that ridiculous photoshopped image of a gruesome imaginary scene that was posted by Age of Autism. Or the death threats Paul Offit has received. All too often, those who are anti-vaccine attempt to smear or intimidate critics instead of engaging with the substance of their arguments.
The author goes on to discuss anti-vaccine tropes. These include attacking straw man versions of the views of critics, characterising vaccines as ‘unnatural’, pretending to be ‘pro-safe vaccine’ rather than anti-vaccine, the pharma shill accusation, and the Galileo gambit. Here’s what Kata said about just one of the anti-vaccine tropes referred to in the article:
“Vaccines didn’t save us”
Rather than acknowledge the role vaccines played in improving health over recent decades, those gains are instead attributed to factors such as cleaner water, better sanitation, and less crowding . This claim is usually accompanied by graphs  showing deaths from vaccine-preventable diseases were declining before vaccines were introduced. That mortality rates would have been decreasing due to improving medical and supportive care is not explained. Graphs showing decreasing disease incidence after vaccine introduction would be evidence of their efficacy, and are omitted
I’ve written a number of blog posts about individual articles in the mainstream media. Articles that were almost cartoonishly misleading, scaremongering and biased against vaccination. This is far more interesting. What the authors of this paper did was to systematically analyse Spanish and German articles (both online and newspaper editions), focusing on the HPV vaccines. The findings were, perhaps unsurprisingly, slightly worrying. Here are some of the lowlights:
- Results show that 57% of German websites and 43% of German newspaper reports communicated correct estimates of epidemiological data, whereas in Spain 39% of the websites and 20% of the newspaper did so.
- Findings reveal that correct estimates about the vaccine’s effectiveness were mentioned in 10% of German websites and 6% of German newspaper reports; none of the Spanish newspaper reports and 2% of Spanish websites reported effectiveness correctly.
The authors conclude that the media lack balanced reporting on completeness (benefits, harms and side effects), transparency (presentation of benefits and harms in absolute numbers instead of or at least in addition to relative numbers), and correctness (evidence-based information). As well as highlighting problems with media reporting, they offer suggestions for improving it. They recommend that reporting standards, along the lines of Consort and Strobe, should be developed and state that such standards would help consumers identify reliable and balanced information sources and support the use of transparent formats to translate scientific knowledge.
This paper looks at what topics are discussed, who discusses them, and how these people feel about them.
Of the topics discussed, 35% were regarding alleged adverse effects of vaccination. Just 4% were about the diseases the vaccine prevents. While discussion of the supposed risks of the vaccine was the most popular topic, discussion of the real risks of the diseases that the vaccine prevents was barely happening at all.
“Among five author categories, only 4% identified themselves as health professionals.” 47% of authors were in the ‘unstated’ category with most of the others being parents or people with a personal interest in autism or related outcomes. Only 1% identified as being from an anti-vaccine group. It seems that most of the people involved in the online debate were amateurs. There’s nothing wrong with people who aren’t an authority on a subject discussing it, and some amateurs might be very good at finding and interpreting reliable evidence, and explaining to others – but I don’t think it hurts to remind people that when they read discussions about vaccination online they aren’t necessarily reading well-informed discussions.
As for viewpoints, here is the breakdown: 33% were looking for information, 33% were anti-vaccine, 15% did not state their position, 14% were supportive, 5% were ambivalent. So, discussion was essentially dominated by (a) people looking for information and (b) those who are anti-vaccine looking to provide information. Or, more likely in my experience, misinformation.
With the lack of health professionals and participants who were pro-vaccine, and the heavy presence of people with anti-vaccine views, it’s hardly surprising that the supposed risks of vaccination were discussed far more than the known risks of the diseases prevented by vaccination.