The Media on MMR

This makes me very angry.

Yesterday the NHS Information Centre released data showing that take-up of the MMR vaccination was lower than it should be. The national level has stalled at 85%, whereas it really needs to be at 95% in order to achieve “herd immunity” – an unflattering term which simply means that immunity is at a level where it’s impossible for the infection to take hold in the community. A decade ago, this figure stood at 92% and was rising.

This is terrible news and many media outlets have commented on it. Here, for example, are the BBC. the Mail and the Express. All of these stories contain a similar explanation for the drop. Here is the Express:

Confidence in the mumps, measles and rubella vaccine fell after
researchers published a 1998 paper in The Lancet medical journal
suggesting a link between MMR and autism.

Uptake of the jab dropped to around 80% after some parents refused to let their children have the vaccine.

This explanation is, of course, being more than a little economical with the truth. It’s true that in 1998 the Lancet published a paper that claimed to link MMR with autism. But papers in the Lancet don’t generally lead to such a hysterical reaction in the general population. This one wouldn’t have done so either if the media hadn’t picked up the story and built it up in such a disgraceful manner.

The point of publishing a paper in an academic journal like the Lancet is for other qualified academics to examine the methods and the results of a study and to draw their own conclusions as to the quality of the research and the reliability of the findings. And in this case, the methods were extremely questionable and the findings were completely untrustworthy.

But that didn’t matter. Andrew Wakefield, who lead the study which the paper was reporting on, held a press conference calling for the suspension of the MMR vaccination and it was this which was reported in the press rather than other doctors’ doubts about the reliability of his research.

Very quickly the MMR/autism link worked its way into the public consciousness and everyone “knew” that responsible parents didn’t give their their children the MMR vaccination. Hence the massive fall in immunisation and a couple of quite scary epidemics of measles in the last few years.

All of which makes it a bit galling to read yesterday’s stories in the press. The same media outlets which drummed up the hysteria in the first place are now reporting on the drop in immunisation. Here’s the BBC:

The study has since been discredited, but confidence has been slow to return in the combined measles, mumps and rubella vaccine.

That’s accurate, I suppose, but it hardly makes it clear that the study was discredited almost immediately but that media outlets took years to listen and to drop their anti-MMR campaigns.

The problem seems to be that many of the original news stories were written by journalists who didn’t know anything about how science works. Just because some doctor stands up and says that something is true, that doesn’t necessarily mean that it is true. The study needs to be examined closely before pronouncements like this can be made. Andrew Wakefield should not have held that press conference and he’s currently being investigated by the General Medical Council for many mistakes he made in the course of this study.

If you’re interested in finding out more about this story and just how badly people were mislead by the media, I strongly recommend Ben Goldacre‘s recent book Bad Science. The final chapter covers the whole sorry tale in some detail. The rest of the book is well worth reading too.

The moral of the story is: don’t trust science stories that aren’t written by people who understand science.