Difficulties in achieving and maintaining the goal of measles elimination in Bulgaria

Abstract

Measles is a disease with almost a hundred year history of existing registration in Bulgaria and has been subject to mass immunization since 1969. In 2017, after a three-year period with a low number of measles cases registered, an epidemic upsurge has been recorded affecting 3 of the total 28 regions in the country. The purpose of this study was to analyze the changes of measles morbidity in Bulgaria over the period of 1921-2017 and focus on the epidemiological characteristics of the last outbreak in the region of Plovdiv in 2017. For the whole period (1921-2017) the average measles morbidity amounts to 157.69%ооо, decreasing from 525.02%ооо in 1921 to 2.32%ооо in 2017, with 99.5% rate of reduction. In the period prior to vaccination the average morbidity was 247.14%ооо while in the vaccination period it was 70.08%ооо. The ARIMA model could be used as a short-term forecast to predict the morbidity rate. Against the background of the downward tendency in morbidity this study reports a small measles outbreak in Plovdiv, involving 141 cases, after three years of no local virus transmission in the country. An unvaccinated child who returned from abroad probably imported the disease. The measles cases were mainly Roma children and a large number of them were infants. The low intensity and prolong course of the outbreak was indicative of relatively high vaccination coverage of the population. To achieve measles elimination goals, efforts must be made to strengthen surveillance and increase the vaccination coverage, targeting children and especially Roma children.

Keywords: Children; Enfants; Measles; Morbidity; Morbidité; Outbreak; Rougeole; Vaccination; Épidémie.