Introduction: In October 2024, an alert was issued at a military prison in Kinshasa, Democratic Republic of the Congo, of a possible mpox outbreak among the detainees. We invested the alert to confirm the outbreak, institute control measures, and prevent further escalation of the situation, given the confined nature of the prison. Methods: An outbreak investigation team was constituted. A suspected case of mpox was defined as any person in the prisons presenting a fever (temperature ≥ 38°C) or an acute fever accompanied by symptoms of mpox, or any person presenting one or more maculopapular rashes or crusts between October 2024 and December 30, 2024. We conducted an active search for suspected mpox cases, identified and tested the contacts. We conducted environmental analyses and identified gaps in surveillance, as well as infection prevention and control (IPC) measures present in the prison. Results: Of the 135 people detained in the prisons, 88 detainees (65.18%) were tested as part of active case finding and contact tracing, and 45 of the 88 suspected cases (51.13%) tested positive for mpox. The median age of the positive patients was 41 years (1st Quartile 24 years – 3rd Quartile 46 years). An outbreak of mpox was confirmed, introduced by a new inmate from outside the prison. All new intake of inmates was stopped to relieve congestion and allow for a certain degree of physical distancing among inmates. Visitors were also prevented from further interactions with the inmates as a control measure to prevent escalations. Preventive measures were instituted, congestion was relieved, and infected cases were treated as per existing protocol. Conclusion: An outbreak of mpox was confirmed in the prisons. The crowded prisons, combined with ineffective preventive measures, probably facilitated the spread of the outbreak. We recommended strengthening the surveillance measures, improving health preventive measures, and vaccinating the community outside of the prisons in the Health Zone and inmates and personnel in the prisons.
Levis et al. (2026) studied this question.