First imported cases of MPXV Clade Ib from Goma, Democratic Republic of the Congo.

Background The ongoing mpox outbreaks in the Democratic Republic of the Congo (DRC) resulted in >71,000 suspected cases from 01 January 2024 to 02 February 2025. Clade Ib mpox virus (MPXV) emergence has heightened public health concern due to observed sustained human-human transmission and spread to multiple non-endemic East African countries. Clade Ib outbreaks have been marked by epidemiologic deviations from classic Clade Ia zoonotic transmission-Clade Ib instead has been observed among adult populations and transmission via sexual contact. With the continued expansion of Clade Ib across the region, containment and mitigation measures may need to be adapted to best fit this novel MPXV clade.Methods Case investigation and epidemiological assessment data as well as whole viral geonome sequencing was analyzed from confirmed mpox infected individuals in the Goma region. Case demographics and clinical presentation data was also assessed from suspected mpox cases in the region.Results We report the first introduction of Clade Ib into North Kivu province through close contact transmission. We also report limited human-human Clade Ib transmission chains among children <15 years in the Mudja internal displaced persons camp. We further present evidence of APOBEC3 mutations and genomic links between these North Kivu cases with the larger ongoing Clade Ib outbreak in Kamituga, South Kivu.Conclusions Given the expansion of regional mpox outbreaks and populations considered at-risk, these findings underscore how mpox case investigations and community messaging should include considerations for non-sexual human-human transmission of Clade Ib that includes children <15 years.Mpox virus, which is endemic in tropical, forested regions of Central and West Africa, has resulted in mpox outbreaks in the Democratic Republic of the Congo (DRC) with historic infections, including more than 71,000 suspected cases reported between January 2024 and February 2025. In recent years, shifting clinical and epidemiological characteristics have been reported for Clade I Mpox virus (MPXV), which is endemic in DRC. This includes the emergence of a new subclade, Clade Ib MPXV, first identified in South Kivu, DRC, in 2023. We report the first introduction of Clade Ib into North Kivu province through close contact transmission. This includes limited human-human transmission of MPXV among children in an internally displaced persons camp, raising concerns regarding undetected transmissions among these vulnerable groups. We further present evidence for links between these North Kivu cases with the larger ongoing outbreak in Kamituga, South Kivu. These findings underscore how mpox case investigations and community messaging should include considerations for non-sexual human-human transmission of Clade Ib that includes children and vulnerable populations.