EPIDEMIOLOGICAL CHARACTERISTICS OF MEASLES

Abstract

Measles is a highly contagious viral disease that continues to pose a serious public health challenge despite the availability of an effective vaccine. It is caused by the measles virus, an RNA virus belonging to the genus Morbillivirus. The disease is transmitted through airborne droplets and direct contact with respiratory secretions, allowing rapid spread in susceptible populations. Measles primarily affects unvaccinated individuals, especially children, but outbreaks increasingly involve adolescents and adults due to gaps in immunization coverage. Epidemiologically, measles is characterized by high transmissibility, periodic outbreaks, seasonal variation, and a strong dependence on population immunity levels. The incubation period ranges from 7 to 14 days, and infected individuals are contagious several days before and after the onset of rash, contributing to silent transmission. Global epidemiological data show that measles incidence rises sharply when vaccination coverage falls below the herd immunity threshold of approximately 95%. Developing countries experience higher morbidity and mortality due to malnutrition, vitamin A deficiency, and limited access to healthcare services. Although global vaccination programs have significantly reduced measles-related deaths, recent years have seen a resurgence of outbreaks linked to vaccine hesitancy, migration, and disruptions in routine immunization services. Understanding the epidemiological characteristics of measles is essential for effective disease surveillance, outbreak prevention, and implementation of elimination strategies.