Measles, the Media and the Dunning-Kruger Effect

The CFR has just released a map showing the incidence of vaccine-preventable diseases worldwide. You can click by VPD to see how different countries are doing by preventable illness. I find it entirely shameful that the UK ranks lower than most developing countries – but how can this have happened?

Ever more studies like this one published by the CDC in the Journal of Pediatrics [sic!] confirm fears of a link between vaccines and autism are unfounded – this one just backs up the conclusions of so many other studies.

In the absence of any good data showing harm from vaccination, why do so many people still expose their and others’ children to preventable diseases that risk significant morbidity and even death?

For example in the USA 1/3^rd of parents believe vaccines cause autism, and 1 in 10 parents refuse or delay vaccinations because they think they know better than the CDC and medics expert in the field.

Let me state my biases up front. 

I believe that sanitation and immunisation have transformed public health; more so even than antibiotics. And this isn’t blind faith; science is a culture of doubt, not faith and I think you’d be hard pressed to find anyone working in microbiology, public health or infection control who would disagree with me.

Yes, better nutrition, education and lots of other things also play a part in our life expectancy being ~80 and rising whereas 100 years ago the average lifespan was only 45 – but the correlation between the disappearance of VPDs and the introduction of their respective vaccines cannot be explained away by hand washing and better sewerage.

Also I tend to give more weight to published data that I can review for myself so I can check for biases and fallacious arguments. And I can do that – there’s a world of difference between being able to understand a scientific paper and being able to critically evaluate it.

Also some journals are better than others and just because something has been published doesn’t necessarily make it relaible.

That’s how science works – we publish our data so others can replicate and agree or challenge. It’s like a polite bar brawl and that’s why so many of us like it.  Some studies are better than others and there is some utter nonsense published in ‘learned’ journals – take a look at this for an example; it argues that quantum theory provides a model for the effectiveness of homeopathy (water). Lots of science-y words but it’s quite simply – to use the proper scientific term – Utter, Utter Bollocks (µ²B). More examples later.

Anyway, back to the point. There were recent cases in the American National Vaccine Injury Compensation Program (aka the ‘Vaccine Court’) that compensated two individuals based on gossamer-thin evidence which is being hailed as a ‘vindication’ of Andrew Wakefield. It isn’t and I’ll dissect that argument if anyone’s interested – but let’s start with the MMR / autism link and the former Dr Wakefield.

Tempting though it is to get into a huge ad hominem against this man let’s stick to the facts rather than fall prey to the logical fallacies such as ad homs that regularly feature in arguments against immunisation. The facts are:

1. Two years before the infamous February 1998 Lancet article proposing a link between the MMR vaccine and autism Wakefield’s group was paid £435,643 in fees plus £3,910 expenses by solicitor Richard Barr, then of the firm Dawbarns looking to prove a link between MMR and autism for a class action against vaccine manufacturers.
2. A year before the Lancet article Wakefield filed a patent for a single vaccine claiming a link between MMR, measles, irritable bowel syndrome and regressive behavioural diseases.
3. While the Lancet paper was quite nuanced and circumspect in its claims Wakefield fuelled a media frenzy – with the results we are seeing now.
4. He was later struck off for not revealing the conflicts of interest (1 & 2 above) as well as conducting unwarranted, unnecessary and unauthorised procedures on autistic children including colonoscopies and lumbar punctures.
5. On 28^th January 2010 the GMC described him as ‘dishonest’, ‘unethical’ and ‘callous’ and he was found guilty on 4 counts of dishonesty and 12 counts involving the abuse of vulnerable autistic children.

Wakefield is not the only one to blame; I’ll come to my disdain for the reporting of science in the popular meeja in a moment but if my central premise – that vaccines are hugely beneficial and Wakefield was a liar and a cheat who falsified data for personal gain – is correct why is he still viewed as a hero in some quarters and why do so many otherwise intelligent people find the whole anti-vaccine argument so persuasive?

The Dunning-Kruger Effect is a common cognitive bias that leads people to greatly overestimate their skill in a particular area relative to their actual level of competence. We all suffer from it.

We not only underestimate our lack of competence, we tend to believe we are way more competent than anyone else, especially an expert. DK has been – unfairly – summarised as being “too stupid to know how stupid you are” but this is a gross oversimplification. DK manifests itself in several ways.

People who are genuinely expert tend to downplay their knowledge or ability and underestimate their skill in comparison with others. They often overestimate others’ ability to understand their field.

“Well, it’s really very simple…”

This is counterbalanced by us non-experts who overestimate our skill – to quote Dunning and Kruger:

“This overestimation occurs, in part, because people who are unskilled in these domains suffer a dual burden: not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realise it.”

But don’t mistake DK for stupidity. Look at Linus Pauling: two Nobel Prizes and went totally off the rails regarding Vitamin C (elements of the Peter Principle here) or James Watson, co-elucidator of the structure of DNA and now a complete fruitcake.

The relevance of DK to the vaccine debate is that people who are unused to critically evaluating scientific data (rather than just reading the abstract) will be less likely to be able to discriminate between Cargo Cult Science, Tooth Fairy Science, a good scientific study or one riven with logical flaws or iffy methodology (such a sampling errors or poor blinding or the other things we look for to pick holes in others’ work).

The problen is people assume that if they are competent or successful in other areas they are quite capable of making these evaluations. Perhaps this is why it appears that the middle classes supposedly are the least likely to take up MMR – but the data here is sketchy (savour the irony that I’m not adverse to anecdote if it supports my position and I can’t be arsed to find the proper reference!)

People have taken against vaccines ever since Jenner suggested inoculating people with zits scraped off cows’ arses. And so much of the anti-vaccine information out there on the Interwebs looks plausible and persuasive. There are plenty of case studies (anecdotes, not data!) and opinion from all sorts of people who sound like they are well informed. Some are easy to spot: anyone recommending that colloidal silver / Echinacea / vitamins / supplements as being more effective than vaccines etc with a link to buy them is a woo merchant.

Or those promoting the Naturalistic Fallacy. Oprah Winfrey is renowned for her love of alt-med woo and some British TV shows aren’t far behind, apparently (I can’t claim expert knowledge of this as I have to work for a living and so miss daytime TV).

But a key differentiator is the use of anecdote. Most diseases are self-limiting (you get better or die) and if getting better coincides with an intervention people credit the intervention – this is another fallacy called confirmation bias. (This is why men never put the toilet seat down, incidentally.)

Apart from those who refuse to vaccinate their kids point blank there are those who pick and choose which vaccines or alter the schedule. The people working in public health who make these decisions are very, very bright people who are expert in their fields and the committees that come up with vaccine schedules or which ‘flu strains to put in next year’s vaccine are the cream of the crop.

I am not an expert in immunology but as a microbiologist I have a reasonable working knowledge of the subject and as it’s not far from my comfort zone / dubious expertise I can read the academic literature without fear.

I don’t challenge the vaccine schedule but that’s not through blind faith or lack of research on my part – it’s because I haven’t found a single study that’s worth a light that links vaccines with any of the pervasive developmental disorders others are claiming. Or much else that gives me significant pause for thought when getting my kids (aged one and five) stabbed the day a particular vaccine comes on to the schedule. As I write this my youngest is having his first MMR shot.

So, be informed. Be concerned by all means. Take an interest. But remember: smallpox – history. Polio – history. In the US immunisation has bought death due to vaccine-preventable illness down by 99%.

But globally over 2 million kids still die each year from the vaccine-preventable illnesses that used to kill about 25% of us and have been all but eradicated in the West.

Until now. 

I think in this case Jorge de Santayana y Borrás had it right – those who fail to learn from history are doomed to repeat it.