1. The preliminary issue to be determined by the court is, can pertussis vaccine cause permanent brain damage in young children? The question relates to pertussis vaccine manufactured in the United Kingdom and applies to all children whether or not they were neurologically normal before vaccination. The burden of proof rests on the Plaintiff and the standard of proof is that of the balance of probability. It must be shown that it is more likely than not that the vaccine can cause permanent brain damage.
2. The medical and expert opinion is deeply divided on the issue.
3. The question is not answered by showing that there is a respectable and responsible body of medical opinion that the vaccine can, albeit rarely, cause permanent brain damage, or that this view is/may be more widely held than the contrary.
4. Similarly the advice contained in the contra-indications against pertussis vaccination . . . cannot be relied upon as though it were evidence . . . that the vaccine in fact causes permanent brain damage.
5. Reports of . . . encephalopathy resulting in . . . brain damage or death where the onset occurs shortly after DTP vaccination, raises the hypothesis that the vaccine may cause brain damage or death. It does not prove the hypothesis. Such reports do not take account of events occurring by chance, for which no explanation can be found. What they do establish is that encephalopathy resulting occasionally in permanent brain damage or death does sometimes occur in close temporal proximity to pertussis vaccination.
6. I have reviewed the evidence and reasoning of the Plaintiffs and Defendants' expert witnesses . . . . I have found myself more impressed both by the cogency and quality of the evidence and reasoning of the experts called on behalf of the Defendants.
7. When I embarked on consideration of the preliminary issue, I was impressed by the case reports and what was evidently a widely held belief that the vaccination could, albeit rarely, cause permanent brain damage. I was ready to accept that this belief was well founded. But over the weeks that I have listened to and examined the evidence and arguments, I have become more and more doubtful that this is so. I have now come to the clear conclusion that the Plaintiff fails to satisfy me on the balance of probability that pertussis vaccine can cause permanent brain damage in young children. It is possible it does, the contrary cannot be proved. But in the result the Plaintiff's claim must fail.
A survey of the first year of operation of the new procedure affecting the conduct of clinical trials in the United Kingdom.
