A prospective study of parapareses in western Sweden

As a consequence of a WHO inquiry about possible complications to poliomyelitis immunization, a prospective incidence study was performed during 1971 in the western region of Sweden, in order to obtain data relevant to the inactivated vaccine used here. After rejection of surgical and secondary cases, the study consisted of 10 Guillain-Barré cases, three incipient MS cases, two infectious and one probably vascular case. By using a procedure of retrospective controls it was demonstrated that the efficiency of prospective case ascertainment is dependent on diagnosis. The incidence of de novo parapareses as defined was approximately 1.7/100,000/year of which 1.0/100,000/year was due to MS. CSF and virological investigations were performed early in prospective cases, in MS cases within 5 to 11 days after onset, and it was shown that no changes occurred in later CF titrations. Routine virological tests did not contribute to diagnosis in patients having paraparesis. No vaccine-associated cases of paraparesis occurred during the 1-year period of the study.