West Africa's Clade II Mpox Outbreak Expands
July 23, 2025
The World Health Organization’s recent decision to maintain mpox as a Public Health Emergency of International Concern underscores the virus’s persistent and evolving threat, particularly in West and Central Africa. With Clade II outbreaks now endemic in Liberia and Sierra Leone and Clade I cases confirmed in Cameroon, the virus is spreading across gender lines and through both sexual and nonsexual contact. The CDC has issued Level 2 travel advisories and recommends mpox vaccination for travelers to the region. As Africa draws increasing global tourism, preemptive vaccination and education must become core strategies to mitigate risk and contain further transmission.
The World Health Organization’s reaffirmation of mpox as a Public Health Emergency of International Concern is both timely and warranted. More than five decades after the first human case emerged in the Democratic Republic of the Congo, the virus has continued to evolve and spread, now presenting a formidable challenge across Central and West Africa. Most recently, outbreaks of Clade II mpox have become endemic in Liberia and Sierra Leone, with new Clade I infections emerging in Cameroon, including in children. Unlike the global mpox outbreak of 2022, which disproportionately affected men who have sex with men, current African outbreaks involve nearly equal rates among males and females, with confirmed transmission via sexual and nonsexual intimate contact.
This pattern highlights a concerning shift in the virus’s epidemiology—one that demands renewed attention from both national health ministries and international agencies. The U.S. Centers for Disease Control and Prevention (CDC) has updated its Travel Health Advisory to Level 2: Practice Enhanced Precautions, recommending that travelers to Liberia and Sierra Leone receive the JYNNEOS® vaccine. Given that over 74 million tourists visited Africa in 2024, the stakes for uncontrolled mpox transmission are substantial.
The broader implications are clear: endemic mpox in high-traffic regions with under-resourced healthcare systems could catalyze further international spread. Vaccine deployment must be accelerated, especially to protect high-risk populations and health workers. Surveillance, public health education, and clinical preparedness must also be scaled up across affected regions.
International travel, if unmanaged, risks serving as a vector for wider outbreaks. With both Clade I and Clade II variants in circulation, and inconsistent vaccine uptake, the window to contain mpox is narrowing. Coordinated, science-based action is critical to interrupt transmission and protect both local communities and the global public.