A story in the Times the other day claimed:

‘The triple measles, mumps and rubella injection does not increase the risk of Crohn’s disease, a study has shown. It has been suggested that the controversial vaccine raises the risk of Crohn’s — chronic inflammation of the intestine — as well as autism. The supposed link with autism has been the subject of many studies and has been rejected by the vast majority of experts. But a possible link with Crohn’s has not been studied, leading to some confusion among parents deciding if their child should have the MMR jab. Now Valerie Seagroatt, a statistician, has looked at rates of Crohn’s disease after the triple vaccine was introduced in Britain in 1988. Writing in the British Medical Journal, she concludes: “The introduction of MMR vaccine, replacing the single measles vaccine, was not associated with an increase in Crohn’s disease.”’

The study in question was published in the British Medical Journal. But now two rapid responses to this study show how misleading it was. The first startling point is that Andrew Wakefield, the gastro-enterologist at the centre of the MMR controversy, never claimed that MMR did cause Crohn’s. He claimed instead that it caused a completely new kind of bowel disease. So Seagott’s introduction which says:

‘It has been hypothesised that the measles, mumps, and rubella vaccine (MMR vaccine) increases the risk of autism and Crohn's disease’

is entirely misleading, and her attempt to investigate such a link quite irrelevant.

The other response points out that Seagrott states:

‘"I restricted the analysis to emergency admissions as these were probably less susceptible to changes in thresholds for admission and clinical practice than elective admissions"’

to which the correspondent witheringly responds:

‘This method pretty much guarantees that data relating to any ASD child, including PDD diagnosed child with Crohn's disease was not included in the study. The likelihood of anything for any of these children being diagnosed during an emergency admission is less than that of a somewhat small snowflake in a somewhat much larger hell fire. It can take four people to hold some of these children down just to take a blood test. The one problem parents of these children have had is that they have not been able to get proper diagnoses of their children's ailments. The failure of paediatric medicine and the NHS in this context is a common cause of complaint. Many complain they can get no treatment of any kind from the NHS for their children and that is particularly for those children with the most distressing disintegrative disorders.

’In the circumstances the statement that emergency admissions 'were probably less susceptible to changes in thresholds for admission and clinical practice' has to be questioned. On what science is such an assumption based? Where are the references. How was this assumption validated? Most importantly, why was this assumption made in the first place when anyone familiar with the issues over MMR caused autism-like and other conditions would know immediately it was invalid. This new paper is a good example of why it is necessary to be wary of people stepping outside their usual areas of expertise to hold forth on topics which may not be as close to their fields as might be desirable.’

Once again, an attack on Wakefield raises more questions than it answers.

Posted by melanie at May 15, 2005