Measles in developing countries. Part I. Epidemiological parameters and patterns.

This paper presents a review of published data concerning the epidemiology of measles in developing countries. Simple mathematical models provide a framework for data analysis and interpretation. The analyses highlight differences and similarities in the patterns of transmission of the measles virus in developed and developing countries. Whilst the rate of loss of maternally derived immunity to measles is broadly similar, the average age at infection is much lower, and case fatality rates are much higher in developing countries. Data analysis also serves to illustrate inter-relationships between different kinds of epidemiological data. Thus, for example, in order to correctly interpret an age stratified serological profile from a developing country it is necessary to have information on the rate of decay of maternal antibodies and age specific case fatality rates. To determine the probable impact of a given vaccination programme, information on the birth rate in the community concerned is also required. A discussion is given of the epidemiological data required in order to effectively design a community based vaccination programme aimed at the eradication of measles.