BACKGROUND : In September 2023, monkeypox virus (MPXV) clade Ib emerged in Kamituga, a mining zone in South Kivu, Democratic Republic of the Congo (DRC), primarily through sexual transmission.AIMWe aimed to investigate cases in a MPXV clade Ib outbreak in Uvira, eastern DRC.

METHODS : From June to October 2024, we collected demographic, exposure and clinical data from suspected mpox cases at Uvira hospital and in households. The virus was identified by PCR. We investigated putative transmission patterns, disease severity and risk factors.

RESULTS : We identified 973 suspected cases: 415 (42.7%) were tested with PCR and 322 (77.6%) were confirmed. The median age of suspected cases was 9 years (interquartile range (IQR): 3-20 years), with 620 (63.7%) aged < 15 and 344 (35.4%) < 5 years. Severe disease (≥ 100 lesions) was more common in cases aged < 15 years (25.6%; 142/554) than others (16.1%; 49/304; p < 0.001). Twenty-two (12.2%) of 181 cases aged < 5 years had acute malnutrition. Seven cases died; the overall case-fatality ratio was 0.7%, and in infants (aged < 1 year) it was 3.9% (5/127). Of 329 suspected cases tested for HIV, six (1.8%) were positive. Nineteen (14.5%) of 131 females aged 15-49 years were pregnant. Most reported exposures to suspected mpox cases occurred in households (67.9%; 298/439). Sexual (6.0%; 19/318) or healthcare-related occupational exposures (1.4%; 6/417) were less common. Animal exposures were few (5.0%; 39/776) and predominantly domestic (97.4%; 38/39).

CONCLUSION : This child-centred outbreak, driven by non-sexual transmission, underscores the need for paediatric vaccines, nutritional support and household interventions. Adult-focused responses alone may be insufficient to control the outbreak.