Infantile spasms and pertussis immunisation.

The possible roles of pertussis immunisation and of other factors in the aetiology of infantile spasms were investigated by analysis of 269 cases reported to the National Childhood Encephalopathy Study. In 34% of the cases an antecedent factor which may have caused infantile spasms was identified; the commonest of these were perinatal hypoxia (38 cases) and tuberous sclerosis (16 cases). Case-control analyses showed no significant association between infantile spasms and pertussis immunisation in the 28 days before onset. There was, however, some clustering of cases immunised with either diphtheria-tetanuspertussis or diphtheria-tetanus vaccines in the 7 days before onset. The excess compared with controls was compensated for by a corresponding deficit over the remaining period up to 28 days. It is suggested that these vaccines do not cause infantile spasms but may trigger their onset in those children in whom the disorder is destined to develop.