Bad Science (25 page)

But we should return to the point. If there was little science, then what
did
appear in all these long stories on MMR? Going back to the 2002 data from the ESRC, only a quarter mentioned Andrew Wakefield, which seems odd, considering he was the cornerstone of the story. This created the erroneous impression that there was a large body of medical opinion that was suspicious of MMR, rather than just one “maverick.” Less than a third of broad-sheet reports referred to the overwhelming evidence that MMR is safe, and only 11 percent mentioned that it is regarded as safe in the ninety other countries in which it is used.

It was rare to find much discussion of the evidence at all, as it was considered too complicated, and when doctors tried to explain it, they were frequently shouted down, or worse still, their explanations were condensed into bland statements that “science had shown” there was nothing to worry about. This uninformative dismissal was pitted against the emotive concerns of distressed parents.

As 2002 wore on, things got really strange. Some newspapers made MMR the focus of a massive political campaign, and the beatification of Wakefield reached a kind of fever pitch. Lorraine Fraser had an exclusive interview with him in the
Telegraph
in which he was described as “a champion of patients who feel their fears have been ignored.” She wrote a dozen similar articles over the next year (and her reward came when she was named British Press Awards Health Writer of the Year 2002, a gong I do not myself expect to receive).

Justine Picardie did a lavish photo feature on Wakefield, his house, and his family for the
Telegraph
Saturday magazine. Andy is, she tells us, “a handsome, glossy-haired hero to families of autistic children.” How is the family? “A likeable, lively family, the kind you would be happy to have as friends, pitted against mysterious forces who have planted bugging devices and have stolen patients’ records in ‘apparently inexplicable’ burglaries.” She fantasizes—and I absolutely promise you I’m not making this up—about a Hollywood depiction of Wakefield’s heroic struggle, with Russell Crowe playing the lead “opposite Julia Roberts as a feisty single mother fighting for justice for her child.”

The Evidence on MMR

So what is the evidence on the safety of MMR?

There are a number of ways to approach the evidence on the safety of a given intervention, depending on how much attention you have to give. The simplest approach is to pick an arbitrary authority figure: a doctor, perhaps, although this seems not to be appealing (in surveys people say they trust doctors the most and journalists the least; this shows the flaw in that kind of survey).

You could take another, larger authority at face value, if there is one that suits you. The Institute of Medicine, the Royal Colleges, the NHS, and more all came out in support of MMR, but this was apparently not sufficient to convince. You could offer information: an NHS website at mmrthefacts.nhs.uk started with the phrase “MMR is safe” (literally) and allowed the reader to drill down to the detail of individual studies.
²⁰
But that too did little to stem the tide. Once a scare is running, perhaps every refutation can seem like an admission of guilt, drawing attention to the scare.

The Cochrane Collaboration is as blemishless as they come, and it has done a systematic review of the literature on MMR, concluding that there was no evidence that the vaccine is unsafe (although the story didn’t appear until 2005). This reviewed the data the media had systematically ignored: What was in it?

If we are to maintain the moral high ground, there are a few things we need to understand about evidence. First, there is no single golden study that proves that MMR is safe (although the evidence to say it is dangerous was exceptionally poor). There is, for example, no randomized controlled trial. We are presented instead with a huge morass of data, from a number of different studies, all of which are flawed in their own idiosyncratic ways for reasons of cost, competence, and so on. A common problem with applying old data to new questions is that these papers and data sets might have a lot of useful information, which was collected very competently to answer the questions that the researchers were interested in at the time, but that isn’t perfect for your needs. It’s just, perhaps, pretty good.

Smeeth et al., for example, did something called a case-control study, using the GP Research Database. This is a common type of study, in which you take a bunch of people with the condition you’re looking at (“autism”) and a bunch of people without it, then look to see if there is any difference in how much each group was exposed to the thing you think might be causing the condition (“MMR”).

If you care who paid for the study—and I hope you’ve become a bit more sophisticated than that by now—it was funded by the Medical Research Council. It found around thirteen hundred people with autism and then got some “controls,” random people who did not have autism, but with the same age, sex, and general practice. Then they looked to see if vaccination was any more common in the people with autism or the controls and found no difference between the two groups. The same researchers also did a systematic review of similar studies in the United States and Scandinavia, and again, pooling the data, found no link between MMR and autism.

There is a practical problem with this kind of research, of course, that I would hope you might spot: most people
do
get the MMR vaccine, so the individuals you’re measuring who
didn’t
get the vaccine might be unusual in other ways—perhaps their parents have refused the vaccine for ideological or cultural reasons, or the child has a preexisting physical health problem—and those factors might themselves be related to autism. There’s little you can do in terms of study design about this potential “confounding variable,” because as we said, you’re not likely to do a randomized controlled trial in which you randomly don’t give children vaccines; you just throw the result into the pot with the rest of the information, in order to reach your verdict. As it happens, Smeeth et al. went to great lengths to make sure their controls were representative. If you like, you can read the paper and decide if you agree.

So “Smeeth” was a “case-control study,” in which you compare groups that had the outcome or not, and look at how common the exposure was in each group. In Denmark, Madsen et al. did the opposite kind of study, called a cohort study: you compare groups that had the exposure or not, in order to see whether there is any variation in the outcome. In this specific case, then, you take two groups of people who either had MMR or didn’t and then check later to see if the rate of autism is any different between the two groups.

This study was big—very big—and included all the children born in Denmark between January 1991 and December 1998. In Denmark there is a system of unique personal identification numbers, linked to vaccination registers and information about the diagnosis of autism, which made it possible to chase up almost all the children in the study. This was a pretty impressive achievement, since there were 440,655 children who were vaccinated and 96,648 who were unvaccinated. No difference was found between vaccinated and unvaccinated children in the rates of autism or autistic spectrum disorders and no association between development of autism and age at vaccination.

Anti-MMR campaigners have responded to this work by saying that only a small number of children are harmed by the vaccine, seemingly inconsistent with their claims that MMR is responsible for a massive upswing in diagnoses of autism. In any case, if a vaccine caused an adverse reaction in a very small number of people, that would be no surprise; it would be no different from any other medical intervention (or, arguably, any human activity), and there would be, surely, no story.

As with all studies, there are problems with this huge study. The follow-up of diagnostic records ends one year (December 31, 1999) after the last day of admission to the cohort, so because autism comes on after the age of one year, the children born later in the cohort would be unlikely to have shown up with autism by the end of the follow-up period. But this is flagged up in the study, and you can decide whether you think it undermines its overall findings. I don’t think it’s much of a problem. That’s my verdict, and I think you might agree that it’s not a particularly foolish one. It did run from January 1991 after all.

This is the kind of evidence you will find in the Cochrane review, which found, very simply, that “existing evidence on the safety and effectiveness of MMR vaccine supports current policies of mass immunization aimed at global measles eradication in order to reduce morbidity and mortality associated with mumps and rubella.”

It also contained multiple criticisms of the evidence it reviewed, which, bizarrely, have been seized upon by various commentators to claim that there was some kind of cover-up. The review was heading toward a conclusion that MMR was risky, they say, if you read the content, but then, out of nowhere, it produced a reassuring conclusion, doubtless because of hidden political pressure.

The
Daily Mail
’s Melanie Phillips, a leading light of the anti-vaccination movement, was outraged by what she thought she had found: “It said that no fewer than nine of the most celebrated studies that have been used against [Andrew Wakefield] were unreliable in the way they were constructed.” Of course, it did. I’m amazed it wasn’t more. Cochrane reviews are
intended
to criticize papers.

Scientific “Evidence” In The Media

But the newspapers in 2002 had more than just worried parents. There was a smattering of science to keep things going: you will remember computer-generated imagery of viruses and gut walls, perhaps, and stories about laboratory findings. Why have I not mentioned those?

For one thing, these important scientific findings were being reported in newspapers and magazines and at meetings, in fact, anywhere except proper academic journals, where they could be read and carefully appraised. In May, for example, Wakefield “exclusively revealed” that “more than 95 percent of those who had the virus in their gut had MMR as their only documented exposure to measles.” He doesn’t appear to have revealed this in a peer-reviewed academic journal, but in a weekend color supplement.

Other people started popping up all over the place, claiming to have made some great finding, but never publishing their research in proper, peer-reviewed academic journals. A pharmacist in Sunderland called Paul Shattock was reported on the
Today
program, and in several national newspapers, to have identified a distinct subgroup of children with autism resulting from MMR. Mr. Shattock is very active on antiimmunization websites, but he still doesn’t seem to have got around to publishing this important work years later, even though the Medical Research Council suggested in 2002 that he should “publish his research and come forward to the MRC with positive proposals.”

Meanwhile, Dr. Arthur Krigsman, pediatric gastrointestinal consultant working in the New York area, was telling hearings in Washington, D.C., that he had made all kinds of interesting findings in the bowels of autistic children, using endoscopes. This was lavishly reported in the media. Here is
The Daily Telegraph
:

To the best of my knowledge—and I’m pretty good at searching for this stuff—Krigsman’s new scientific research findings that corroborate Andrew Wakefield’s have never been published in an academic journal; certainly there is no trace of them on PubMed, the index of nearly all medical academic articles.

In case the reason why this is important has not sunk in, let me explain again. If you visit the premises of the Royal Society in London, you’ll see its motto proudly on display:
Nullius in verba
—“On the word of no one.” What I like to imagine this refers to, in my geeky way, is the importance of publishing proper scientific papers if you want people to pay attention to your work. Dr. Arthur Krigsman has been claiming for years now that he has found evidence linking MMR to autism and bowel disease. Since he hasn’t published his findings, he can claim them until he’s blue in the face, because until we can see exactly what he did, we can’t see what flaws there may be in his methods. Maybe he didn’t select the subjects properly. Maybe he measured the wrong things. If he doesn’t write it up formally, we can never know, because that is what scientists do: write papers, and pull them apart to see if their findings are robust.

Krigsman and others’ failures to publish in peer-reviewed academic journals weren’t isolated incidents. In fact it’s still going on, years later. In 2006, exactly the same thing was happening again. us scientists back autism link to mmr, squealed the
Telegraph
. scientists fear mmr link to autism, roared the
Mail
. us study supports claims of mmr link to autism, croaked
The Times
(London) a day later.

What was this frightening new data? These scare stories were based on a poster presentation, at a conference yet to occur, on research not yet completed, by a man with a track record of announcing research that never subsequently appears in an academic journal. In fact, astonishingly, four years later, it was Dr. Arthur Krigsman again. The story this time was different: he had found genetic material (RNA) from vaccine-strain measles virus in some gut samples from children with autism and bowel problems. If true, this would have fitted with Wakefield’s theory, which by 2006 was lying in tatters. We might also mention that Wakefield and Krigsman are doctors together at Thoughtful House, a private autism clinic in the United States offering eccentric treatments for developmental disorders.