The 1991 measles epidemic in Israel.

INTRODUCTION AND METHODS. Prior to the institution of universal childhood vaccination against measles in Israel in 1967, large outbreaks occurred in epidemic cycles at intervals of 2-4 years. The mean annual incidence in the pre-vaccination period, 1950-66, was 470/100,000 per year. With the institution of routine measles vaccination, incidence rates fell, and since 1970 measles incidence has averaged less than one-tenth the pre-vaccination incidence rate, although epidemics occurred in 1975, 1982, 1984-85, and 1991. In this report, based upon cases of measles reported to and investigated by the Ministry of Health, we present an analysis of the 1991 measles epidemic, the measures taken to contain it, and an overview of the prospects for measles control in Israel in the future. RESULTS AND CONCLUSIONS. The 1991 measles epidemic, 1036 reported cases (incidence: 20.0/100,000), began in the south of the country among underimmunized Beduin children and spread to the Jewish population in the south and then to the rest of the country. The highest incidence was in children aged 12-23 months, followed by children less than 12 months of age and children aged 2-4 years. In the main, cases occurred in persons never immunized in the past, but in 37% of cases vaccine failure seems to have occurred. Control measures included mass vaccination of children in the south and lowering the age for routine measles vaccination nationwide to 12 months. Despite very substantial gains towards measles control in Israel, elimination of the disease is not a realistic goal, mainly because the transmission potential of the disease is too high and vaccine coverage and efficacy are not high enough. Trends in measles incidence over the last four decades allow a cautious optimism that measles containment can be achieved.