An unprecedented mpox outbreak in the Democratic Republic of Congo (DRC) in 2023 included the first documented cases of sexually transmitted mpox clade I—a more transmissible and severe version of the virus than mpox clade II, which was responsible for the .

The number of mpox cases and deaths in the DRC surged during 2023, the World Health Organization (WHO) . More than 12 500 suspected cases occurred there over the past year—about double the number in 2020. About 600 people are believed to have died from mpox infection, which translates to a case-fatality rate of 4.6%.