Clade Ib Mpox Outbreak - Kenya, July 2024-February 2025.

Since July 2024, Kenya has been experiencing an mpox outbreak caused by clade Ib Monkeypox virus (MPXV), a newly recognized variant that has spread from the Democratic Republic of the Congo to multiple countries within and outside of Africa. This report describes the characteristics of laboratory-confirmed clade Ib mpox cases in Kenya during the first 7 months of the outbreak. Among 447 suspected cases during July 2024-February 2025, a total of 48 (10.7%) were confirmed by polymerase chain reaction testing. Most confirmed cases occurred along a highway from the Indian Ocean port in Mombasa to Malaba at the Ugandan border, a transportation corridor that links Kenya to other East and Central African countries. Among the 48 confirmed cases, 27 (56.3%) occurred among persons associated with the transportation corridor, including truck drivers (12; 25.0%), sex workers (eight; 16.7%), and persons employed at or near trucking stopovers (seven; 14.6%). Sexual transmission was suspected in 30 (62.5%) cases, based on the patient's history or locations of the lesions; 11 (22.9%) patients also had HIV infection, one of whom died. Clade Ib MPXV in Kenya appears to be primarily sexually transmitted and concentrated in specific groups at high risk for infection. Public health measures, including vaccination, might be most effective if they focus on these specific groups and geographic areas.