Epidemiological Investigation of a Large Mpox Outbreak in the Western Region of Ghana, 2025

Background Mpox, a member of the Orthopoxviral genus in the Poxviridae family, is a zoonotic disease caused by the monkeypox virus (MPXV), with an incubation period spanning 5 to 21 days. Internationally, it is known to spread within sexual networks, particularly among men who have sex with men (MSM). On 12 May 2025, the first case of Mpox was recorded in the Western Region of Ghana, triggering an intense outbreak in the region. We investigated this outbreak to understand and determine its magnitude in the Western Region of Ghana. Methods A cross-sectional study was conducted from May to December 2025. Suspected, probable, and confirmed cases were identified through enhanced surveillance, record reviews, and contact tracing. Cases were confirmed by Real-Time PCR using WHO-supplied reagents for local testing. Results Of the 1,060 suspected Mpox cases, 37.55% (398/1,060) were laboratory-confirmed. The outbreak was propagated, lasting 29 epidemiological weeks with multiple peaks. Most confirmed cases were adults aged 18–45 years (75.63%), with a majority being males (52.26%). Over 70% of cases were concentrated in three urban districts (Sekondi-Takoradi, Tarkwa-Nsuaem, Wassa-Amenfi East). Three fatalities were recorded, resulting in a case fatality rate (CFR) of 0.75%. Conclusion This investigation revealed a prolonged mpox outbreak in the Western Region of Ghana, concentrated among working-age men in urban areas. While vaccination ultimately reduced virus transmission, a significant delay in response highlights the need for improved surveillance, rapid response measures, and sustained community engagement to prevent future outbreaks.