If you’re a regular reader of my page, you’ve probably formed a certain idea about the kind of thing that I do here. You probably expect me to sarcastic about religion, and wax lyrical about science. All in all, that’d be pretty near the mark, but the truth is, I don’t care all that much about religion. If you’re not trying to impose your beliefs on anyone else, or infringe upon the human rights of others, then you’re free to believe whatever you like. Of course, I would prefer that you at least think critically about your religious beliefs but, however deluded I think you are, I’ll stand up and defend this right.
What I do have a problem with, is any attempt to undermine science. This is why I am so ardent in my criticism of the creationism/intelligent design movement. But they aren’t the only perpetrators, and it isn’t them I’m going after this time.
You see, as far as I’m concerned, science is one of the noblest of human endeavours. Curiosity about the universe in which we live is a true human virtue, and that is what science represents - humanity’s best attempt to understand nature. This would be laudable in and of itself, but this is also a fruitful endeavour. Almost every aspect of modern life is made easier by science.
Life expectancy has doubled, worldwide, since the turn of the 20th century. The main impetus to this dramatic improvement being a truly massive reduction in infant and childhood mortality. Before modern medicine, humans were at the mercy of our natural predators - bacteria, viruses, and parasites. Smallpox wiped out 500,000,000 people during the 20th century. The Spanish influenza killed a similar number in a little under four years. Then came effective vaccines. On September 11, 1978, smallpox claimed its last victim. Influenza remains a threat, but is unlikely ever again to kill one third of the people on Earth. Whooping cough, diphtheria, polio. To many of us, these seem like the illnesses of a bygone age. The MMR vaccine is an almost universal event of our early childhood. Or at least, it was.
A brief history lesson…
Back in February of 1998 Andrew Wakefield, a British surgeon, published a paper in prestigious medical journal The Lancet. The paper, a series of twelve case-studies (more on why that’s important later), was published as evidence of a new syndrome of autistic spectrum disorder associated with bowel symptoms. In 8 out of the 12 cases, a link was speculated between the onset of symptoms and the MMR triple vaccine being administered. Quite how this link was arrived at seems questionable, considering the ubiquity of the MMR vaccine, the presumably vast array of confounding variables, and the fact that autism tends to present in early childhood anyway. Wakefield was careful to point out that this study did not establish a causal link between MMR and ‘autistic enterocolitis’, but advised that further research into a possible link should be carried out.
This may even seem reasonable to some people. But let’s think about this. The MMR vaccine is a VERY common intervention - back in 1998, 92% of children in the UK received the MMR vaccine. Autistic spectrum disorders are also fairly common - 0.9% of children now being diagnosed with varying degrees of autistic tendencies. Basic probabilities tell us that we could have expected to find that 0.82% of the population had both received the MMR jab AND been diagnosed with autism. Add in the bowel symptoms (although these were rather poorly-defined) and you may be looking at some reasonably slim odds, but remember, these cases were hand-picked. As I mentioned previously, it seems odd that Wakefield and his colleagues would be so eager to suggest something as commonplace as MMR to be the trigger for this condition as opposed to a more unusual exposure that linked the cases, and indeed you’d be correct in thinking this way. Wakefield was found to have been enlisted to establish such a causal link by parents looking to litigate against the manufacturers of vaccines. He received as much as £400,000 in legal aid money for his research, and in 2010, the GMC (General Medical Council) found him guilty of some three dozen charges that had been established against him, and as of May 2010 he has been struck-off the medical register and cannot legally practice in the UK. Wakefield remains defiant, claiming that he did nothing wrong and that the authorities are simply trying to silence him, and is now lending undeserved credibility to the anti-vaccination cause in the US (who for the most part seem to be only one step away from conspiracy theorists in tin-foil headgear), alongside such intellectual luminaries as former Playboy model Jenny McCarthy (herself a recipient of James Randi’s illustrious Pigasus award - I should know, I’m personally responsible for the inclusion of this information on McCarthy’s wikipedia article, and if that isn’t enough to convince you, here’s Randi himself presenting the award).
But, even if Wakefield’s paper had been published in good faith, it still wouldn’t have proven anything. You see, Wakefield’s paper wasn’t a study of any kind. It was a case series. This is little more than a collection of anecdotal evidence, but these can be of value when studying very rare conditions. If there are only a few hundred people in the world with a given medical condition, you can do little more than make observations about the handful of cases that you have access to.
The gold standard for clinical evidence is what is known as a randomised-controlled trial. In an RCT, you select a group of participants (ideally, these should represent a typical cross-section of the population at large), who you then randomly divide into to groups. One group receives the treatment or intervention you wish to study, while the other is a control group. The control group may be given a placebo, or for comparison, may be given the current first line treatment. In an ideally designed study, neither the patients, nor the clinicians involved, will know who is in either group.
Trials like this provide excellent evidence but, clearly, no-one is going to perform a clinical trial in which you randomly withhold vaccinations from one group of children in order to see whether or not they develop autism. Well, maybe someone would try, but you’d strongly hope that an ethics committee would turn them down.
There are two types of observational study that we could use. In a cohort study, you would find a group of children who had been given the MMR vaccine, and a group of children who hadn’t, and see if there was any difference in the prevalence of autism between the two groups. In a case-control study you would find a group of children with autism, and a group of children without autism, and see if the rate of MMR vaccination differed between them. These studies are not as good as a randomised-controlled trial, as they are open to confounding variables, but if you are able to make sure that the two study groups are as similar as possible, then they can provide fairly strong evidence, especially if enough of them have been carried out.
And, as it happens, they have. In 2004, The Cochrane Collaboration (a volunteer organisation dedicated to evidence-based medicine) performed as systematic review of 31 clinical studies on MMR, finding no statistically significant link with autism. In 2005, an EU meta-analysis of 120 or so studies found that a link between the MMR vaccine and autism was unlikely.
Of course, you’d never have known this from the media reaction. Wakefield’s Lancet paper was published in 1998, but the mainstream media didn’t really pick it up until 2001. By this time, the tide of evidence was already stongly against the link between MMR and autism, but you wouldn’t have known that if you read the British newspapers.
"Fresh safety fears raised over MMR jab"
"New MMR link found to autism"
"MMR - risk of brain disorders?"
"New fear over MMR link with rising autism."
"Dangers of MMR jab covered up."
These are examples of headlines from mainstream British newspapers, some from as late as 2007. In the years between 2001 and 2006, national newspapers carried no less than 4000 stories on MMR, with the majority exaggerating the potential risks and downplaying the strong evidence to the contrary. Of these stories, less than 20% were written by journalists with scientific training. In most cases, they weren’t even consulted at all, leaving people who may well have been incapable of understanding clinical trial findings to dish out public health advice. A localised vaccination scare (these are common - the whooping cough vaccine in the UK, the hepatitis B vaccine in France, thiomersal in the States) went global (Japan actually withdrew the triple vaccine - there has been no drop in autism) and vaccination rates in the UK fell from their 92% peak, to 73% (as low as 61% in some areas). The high uptake rate of the vaccination prior to the scare had, in effect, immunised the population as a whole, making a measles epidemic impossible. In 1998 there were just 56 reported cases of measles in the UK. In 2006, the incidence of measles was 13 times higher, and in 2008, measles was declared endemic in the UK, and there have been several minor epidemics in Europe. An outbreak in Ireland affected 1,500 children, killing three. An outbreak in Bulgaria affected over 27,000, and killed 25. The Netherlands are still trying to control a serious outbreak. Measles can cause severe neurological and respiratory complications, and can lead to blindness, deafness, and brain injury.
Mumps, too, has made a comeback. Mumps had become so uncommon that many junior doctors were unable to recognise the disease, having never seen it before. On average, less than 100 cases were being reported annually. Between 2004 and 2006, there were 70,000 cases and infection rates are still high, especially in young adults. Mumps has serious complications which can lead to hearing damage and infertility.
Finally, some within the media are beginning to distance themselves from the scare - last year, following Wakefield’s striking off, several papers issued retractions and apologised. What they did can fairly be described as a hoax - a particularly insidious hoax that played upon people’s desire to keep their children safe from harm, but which actually led to them exposing their children to some rather unpleasant infectious diseases. Of course it is your choice whether or not to vaccinate your children, but misinformation deprives you of your power to make a meaningful choice. It is the mainstream media’s dishonour, and for me, it will forever place a black mark against their reputation. As for those who were involved in propagating this scare, they have blood on their hands, and they should all be ashamed of themselves.
For a more detailed look at this, and examples of other ways in which science has been undermined in popular culture, I strongly recommend Ben Goldacre’s excellent Bad Science.