Epidemiological Measles Outbreaks Investigation in Nogob Zone, Somali Region, Eastern Ethiopia: Trends and Insights from 2019 To 2024

Abstract

Measles remains a major vaccine-preventable cause of childhood morbidity and mortality, particularly in low-coverage settings. Measles remains endemic in Ethiopia, and Somali Regional State (SRS) experiences high incidence rates despite vaccination efforts. This study aimed to investigate measles outbreaks and provide critical insights into the epidemiological trends. A retrospective descriptive study was conducted using surveillance data from Nogob Zone. All reported measles cases (confirmed, epidemiologically linked, and clinically compatible; n = 2,214) were included through inclusion of complete line lists. WHO case definitions were applied. Data were analyzed using Microsoft Excel, Epi-Info, and ArcGIS 10.8 to generate descriptive statistics, epidemiological curves, attack rates, and spatial maps. From 2019 to 2024, a total of 2,214 measles cases and 58 deaths were reported (case fatality rate: 2.6%), exceeding national rates. Children aged 5–14 years were most affected (42%), followed by those aged 15 years and older (33%). Geographically, Duhun and Garbo woredas had the highest attack rates (18 and 17 per 1,000 population, respectively). The outbreak peaked in 2023, with a decline thereafter. The study shows that Nogob Zone has faced a substantial measles burden, reporting 2,214 cases and a 2.6% case fatality rate between 2019 and 2024. The notably high attack rates observed in Garbo and Duhun woredas, along with a major outbreak surge in early 2023, point to persistent gaps in vaccination coverage and systemic barriers. Strengthening routine immunization, improving surveillance, and implementing targeted catch-up campaigns are recommended to prevent future outbreaks.