Case presentation of patients hospitalised with mpox (subclade Ib/2023sh) including children, adolescents, and adults in South Kivu, Democratic Republic of the Congo: an observational cohort study

BACKGROUND: Mpox is a public health concern in eastern DR Congo. It continues to cause substantial numbers of hospital admissions, with changing demographics including children and adolescents, requiring comprehensive clinical and epidemiological investigation. In this study, we aim to describe the clinical characteristics of hospitalised participants infected with monkeypox virus (MPXV) subclade Ib/2023sh in the Kabare Territory in South Kivu, DR Congo. METHODS: This observational cohort study included patients admitted with suspected mpox to the reference centre of mpox treatment at Lwiro Hospital, South Kivu, DR Congo. Eligible participants must have had, at the time of inclusion, skin lesions compatible with the infection. Individuals who did not present lesions compatible with MPXV infection were also eligible if they had at least one of the following symptoms: fever, cervical lymphadenopathy, or pharyngitis, provided they had been in contact with someone with suspected mpox within the last 21 days. Data from hospital records and standardised clinical forms captured demographics, presenting symptoms and signs, outcomes, and general clinical characteristics. Descriptive analyses and statistics summarised the clinical and epidemiological profiles of participants with molecular confirmation of MPXV subclade Ib/2023sh. FINDINGS: Between Aug 3, 2024, and Feb 8, 2025, MPXV subclade Ib/2023sh was detected in 494 (77%) of 643 participants with a median age of 9 years (IQR 2-24). Participants who were positive for MPXV subclade Ib/2023sh infection were more often female (290 [59%]) and were generally older (median 16 years [4-25]) than male participants (204 [41%]; median age 4 years [1-14]). 300 (61%) of 494 participants were aged 15 years or younger. Fever (444 [90%]), skin lesions or rash (391 [79%]), and dysphagia (279 [56%]) were the most prevalent symptoms. Children aged 0-5 years had a higher frequency of lesions on the head (84 [41%] of 203), face (67 [33%]), neck (23 [11%]), back (27 [13%]), arm (35 [17%]), palm of hand (35 [17%]), chest (46 [23%]), posterior aspect of thighs (40 [20%]), legs (25 [12%]), dorsal foot (45 [22%]), and oral cavity (37 [18%]). 117 (24%) participants had lesions in the oral cavity. Oral cavity and oropharynx swabs were able to detect MPXV subclade Ib/2023sh in the absence of assayable skin lesions. INTERPRETATION: The high proportion of children and adolescents (aged ≤15 years) differentiates our cohort from other clinical descriptions of the novel MPXV subclade Ib/2023sh. Given that, we hypothesise a demographic shift in the target population that contributes to the community spread of mpox in the South Kivu region of DR Congo. Targeted public health measures should consider ways to reduce transmission among children and adolescents. FUNDING: Canadian Institutes of Health Research (CIHR), Canadian Foundation for Innovation, Research Nova Scotia, Dalhousie Medical Foundation, Moderna, Li-Ka Shing Foundation, European & Developing Countries Clinical Trials Partnership (EDCTP). TRANSLATIONS: For the French, Swahili and Mashi translations of the abstract see Supplementary Materials section.