Use of physiotherapy records to monitor the efficacy of a poliomyelitis vaccination programme in Ilorin, Nigeria 1981-1988.

During the 8 years of a poliomyelitis control programme in Ilorin Local Government Area, Nigeria, a maximum of 85% of children aged 12-23 months were estimated to have received three doses of trivalent oral polio vaccine (TOPV). The estimated incidence of paralytic poliomyelitis decreased by 65%, suggesting a low vaccine efficacy of approximately 76% for the currently used TOPV. A more detailed study of TOPV efficacy (eg case control or cohort study) is required, however, to provide a more accurate estimate. Similar low-cost efforts at documenting the impact of TOPV on the incidence of poliomyelitis, using physiotherapy clinics as independent sentinels, are needed from many other centres. To increase the efficacy of the primary series of TOPV in Nigeria, the number of doses constituting the primary series should be increased to four (including one at birth), as recommended by the World Health Organization.