EPI sentinel surveillance for Kwara, 1982-1987.

A comprehensive review of the EPI sentinel surveillance data for Kwara State, Nigeria was conducted for the years 1982--1987 to evaluate programme impact. Measles vaccination coverage moved up from 26 percent in 1984 to between 54 percent and 58 percent in Ilorin, LGA, Kwara State, Nigeria from 1986 to 1988. During the period of review, the annual number of measles cases and the incidence rate of measles reported by the surveillance system has continued to fall from 1985, the year the revised EPI programme was launched in Ilorin LGA. There was infact a forty-one percent reduction in measles incidence in Ilorin LGA in 1987, but measles is still an important cause of preventable morbidity and mortality in the area. Twenty-two percent of reported measles cases occurred in children under nine months of age, children who are younger than the recommended age of vaccination. Two results expected in a partially vaccinated population, a reduction in measles incidence greater than the level of vaccination coverage and a shift in the age-distribution of measles to older children, have not been observed. Measles control in Ilorin LGA will require a vaccination coverage higher than 58 percent. Also, given the age-specific risk of measles infection there, a measles vaccine that would be effective when given before nine months of age would be an important element in controlling measles transmission. Because the epidemiology of measles in Ilorin is a likely consequence of its urban environment, such a vaccine would represent a significant advance toward the control of measles in urban Africa.(ABSTRACT TRUNCATED AT 250 WORDS)