Mpox in the Democratic Republic of Congo
The DRC is the global epicenter of mpox — home to endemic Clade I disease and the origin of the new Clade Ib variant that triggered a WHO PHEIC in August 2024.
Key Data
| Metric | Data |
| Endemic clade | Clade I (Congo Basin) — endemic for decades |
| New variant | Clade Ib — South Kivu, 2023 |
| 2024 suspected cases | >25,000 |
| 2024 deaths | >600 |
| WHO PHEIC declared | August 14, 2024 |
| Health authority | Ministère de la Santé Publique, DRC |
Decades of Endemic Mpox in the Congo Basin
Mpox was first identified as a disease of humans in the DRC in 1970 (in Basankusu, Équateur province) — a young boy initially thought to have smallpox. Since then, Clade I mpox has been endemic in the Congo Basin forest regions of DRC, transmitted primarily from animal reservoirs (squirrels, rats, primates) to humans, and via household contact. For decades, mpox was considered a relatively contained zoonotic disease of remote forest communities. DRC reported thousands of suspected cases annually with case fatality rates in Clade I reaching 3–11% (higher than Clade II's 1–3%).
The Emergence of Clade Ib
Beginning in 2023, a new transmission pattern emerged in South Kivu: Clade Ib mpox spreading efficiently through sexual networks in mining communities and urban centers. Unlike classic Clade I (zoonotic and household), Clade Ib behaves more like the 2022 Clade IIb outbreak (human-to-human via close sexual contact) but with Clade I's higher clinical severity. Clade Ib spread to neighboring countries (Rwanda, Burundi, Uganda, Kenya) via land borders and international travel. The geographic expansion and changed transmission dynamics prompted WHO Director-General Tedros Adhanom Ghebreyesus to declare a PHEIC on August 14, 2024 — only the seventh in WHO history.
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FAQ
The 2022 global outbreak was Clade IIb — a West African clade with lower severity (case fatality rate ~0.1% in high-income countries). Clade Ib is a sub-lineage of Clade I — the more severe Central African clade (historical CFR 3–11%). Crucially, Clade Ib has acquired efficient human-to-human sexual transmission (like Clade IIb) while retaining Clade I's higher severity potential. This combination makes it more concerning than either prior form alone.
Yes. Unlike the 2022 Clade IIb global outbreak (which predominantly affected adult men in MSM networks), Clade I mpox in DRC affects children significantly — particularly those in endemic forest regions who have animal contact or household contact with infected adults. Children under 15 account for a substantial proportion of DRC's mpox cases and deaths. Clade Ib has also been reported in children, particularly in households with confirmed adult cases.
Sources: WHO DRC mpox situation reports; WHO PHEIC declaration Aug 2024; Nature Medicine (Karagoz et al. Clade Ib characterization); Africa CDC mpox response DRC.
Related: Mpox overview · DRC Ebola · USA mpox