MEASLES IN RURAL BANGLADESH - ISSUES OF VALIDATION AND AGE DISTRIBUTION

In the Third World, scientists have described thoroughly the pattern o f measles in Africa. In Asia, however, the epidemiology of measles has been poorly described. In 1989, a measles surveillance system was ini tiated in Matlab, rural Bangladesh in order to monitor measles inciden ce in the area. The population (100000), which has relatively low immu nization coverage, has an excellent demographic surveillance system wh ich allows accurate follow-up. The system works through trained commun ity health workers who visit all households every fortnight and report possible cases of measles. Medical doctors review a proportion of ind ex cases and cases in infants soon after the appearance of the rash. O f the 4673 cases reported in all age groups, 18% were visited by medic s. Confirmation of diagnosis was related to the age at onset and overr eporting by community health workers is documented. The incidence of m easles was estimated at 43% of children <5 years old. Of cases <5 year s of age, 14% occurred below the age at vaccination (incidence rate = 5.5%). A strong seasonal pattern is reported. Case-fatality rates are low. This is the first report which shows the effect of age on reliabi lity of reported measles. It shows the misclassification likely to occ ur when reporting measles in large-scale surveys, particularly in infa nts. It also shows that the pattern of measles in this community resem bles the pattern reported for African communities and calls for a revi ew of immunization strategies with vaccination below 9 months of age.