The issue of MMR vaccination and its alleged side effects has been raised again after one of the authors of a study linking a particular bowel disease and autism has written to the Lancet arguing that we are at risk of a major measles epidemic because of a lack of take up of the MMR vaccine.
Dr [Simon] Murch, of the centre for paediatric gastroenterology at the Royal Free Hospital in London, was one of the authors of a 1998 paper published in the Lancet which looked [at] the connection between inflammatory bowel disease and autistic disorders.
The paper found a connection between bowel problems and autism but did not conclude that MMR was connected to this.
In his letter Dr Murch says:
"An unprotected child is not only at personal danger, but represents a potential hazard to others, including unborn children. Unless vaccine uptake improves rapidly, major measles epidemics are likely in the UK this winter."
I've tried to get my head around the issue by looking logically at the comparative risks but I'm afraid I can't. It seems to me that medical risk is always difficult to measure and explain since we are dealing with moral judgements as much as risk assessment.
Suppose I have a new drug which will cure 10,000 sufferers of a particular chronic condition every year. I also know that there will be adverse reactions and a certain number of people will die each year who without the drug would have lived, albeit with a reduced quality of life because of their original ailment.
How many deaths are 'acceptable' before the drug should be withdrawn? Is this purely a matter of risk assessment?
[I recall one anti-inflammatory drug was withdrawn because of a few cases of adverse reactions, even though it had been shown to be highly effective in treating arthritis. The problem is that the people suffering the adverse reaction (in this case death which is pretty adverse) are not the people whose risk of other events is reduced. I can't give a URL link because I can't recall the name of the drug.]
These are the issues underpinning the MMR debate. For the parent of a child due for vaccination, this isn't a theoretical question, it is intensely personal and they believe that their child's life hangs on the decision they take. As a parent I faced similar concerns when considering vaccination for whooping cough. Similar vaccine damage stories were circulating about that vaccine. We decided to go ahead because the incidence of whooping cough was rising and the increased risk from the disease appeared to outweigh the perceived risk from the vaccine.
The problem is that measles is seen by many as a relatively trivial childhood disease - one of the tribulations of childhood. Of course it isn't but we reach that judgement in a context where the other threats to our children have reduced - we no longer need to worry about cholera, diptheria, polio. Our assessment of the risk is not just a numbers game.