Resurgence of the measles epidemic: situation in Minas Gerais, Brazil

Abstract

This study aims to describe the measles vaccination campaigns that have been carried out in the state of Minas Gerais, Brazil, since 1988; to highlight their importance in the control of the disease, and to pinpoint the age groups at risk during the recent epidemic, which began in 1996, spread all over the country, and declined in 1998. However, the analysis includes only data up to September 1997. The methodology used was based on the birth cohort analysis design. Data compared by cohorts included target population and vaccination coverage for each campaign, and measles incidence rates during the present epidemic. Results show that the more opportunities for exposure to vaccination campaigns, the lesser the risk for having measles in any birth cohort. In 1997, the relative risk for getting measles was 15.38 (IC 95%: 9.89 to 23.93) for the cohort under 2 years of age, which had not had the opportunity to be exposed to any vaccination campaigns, as compared to cohorts between 3 and 19 years of age with two or more opportunities of exposure to vaccination campaigns. On the basis of the experiences analyzed, catch-up measles vaccination campaigns as well as follow-up campaigns--particularly when routine vaccination did not achieve sufficient coverage--have had an outstanding role in controlling the measles epidemic in the state of Minas Gerais. We therefore suggest making the measles vaccine immediately available to all birth cohorts that did not have the opportunity for exposure to past vaccination campaigns and intensifying epidemiological surveillance. Moreover, it is necessary to find ways to improve routine vaccination coverage in order to achieve the 95% goal set by the National Plan to Eliminate Measles by the Year 2000.