Assessment and possible control of endemic measles in urban Nigeria

BACKGROUND: Measles remains as a serious problem of infancy and childhood in the developing world, despite the availability of a vaccine. Increasing urbanization is changing patterns of endemicity. METHODS: A survey of measles in an urban area of Nigeria, using a rapid assessment approach, was carried out to characterize measles in this community. RESULTS: An annual incidence rate of 11.8% among under-fives was found, associated with an acute case fatality rate of 3.3%. This level of endemicity was two orders of magnitude greater than that suggested by official case reports. An endemic, rather than epidemic, pattern was found over the six-month period of the study. Vaccine efficacy was estimated at 26%. Risk factor analyses showed the major risks for measles to be clinic attendance in the month preceding disease, households with more than one mother, and having under-five siblings. Measles itself was the principal risk factor for malnutrition and against survival. CONCLUSIONS: Improved understanding of measles epidemiology and risk factors are prerequisites for effective control. Possible strategies should include vertical vaccination efforts in addition to routine programmes.