The Status of Measles and Rubella Outbreak Detection, Early Alerts, and Response in Eastern Mediterranean Region (EMR), 2023.

Background: Measles and rubella remain major public health concerns in the Eastern Mediterranean Region (EMR), despite regional elimination goals. In 2023, the region experienced an increase in measles outbreaks. This study assessed outbreak detection and response challenges in either case definition or data analysis, in addition to gaps in laboratory and genotyping data integration to improve preparedness and response. Method: A retrospective epidemiological study was conducted using official World Health Organization (WHO) data on measles and rubella (MR) in EMR countries, from 1 January to 31 December 2023. Routine MR surveillance line list, genotyping data and supplemental immunization activity (SIA) reported by countries were used. Results: In 2023, 1206 suspected measles outbreaks were reported in 13 countries; 942 (78%) were confirmed. Rubella accounted for 158 confirmed outbreaks. Children under 5 years old comprised 76% of cases, with 62% zero dose. Timely detection was achieved in only 46% of outbreaks, with wide national variation. Genotype B3 predominated, but missing genotyping data limited verification. Six immunization campaigns occurred; however, outbreaks persisted due to high zero dose, limited targeting, and delayed responses. Conclusions: Persistent immunity gaps, under detection, inconsistent genotyping, and delayed response hindered MR control in EMR. Strengthening surveillance, integrating epidemiological and molecular data, expanding targeted supplementary immunization activities, and ensuring timely response are essential tasks. Standardized outbreak definitions, capacity building, and regular subnational analyses remain critical to regional elimination goals.