A new strain of Monkeypox has been discovered in the Democratic Republic of Congo, according to a preprint study.

The study said the virus strain has “pandemic-potential” and called for “targeted vaccination” efforts.

The virus is believed to be a “zoonotic spillover,” meaning it has jumped from animals to humans.

According to the study, Clade Ib derives from genomes from an outbreak in Kamituga in October 2023.

“The Kamituga mpox outbreak spread rapidly, with 241 suspected cases reported within 5 months of the first reported case,” the study said. “Of 108 confirmed cases, 29% were sex workers, highlighting sexual contact as a key mode of infection. Genomic analysis revealed a distinct MPXV Clade Ib lineage, divergent from previously sequenced Clade I strains in DRC. Predominance of APOBEC3-type mutations and estimated time of emergence around mid-September 2023 suggest recent human-to-human transmission.”

In December 2023, the CDC released a health alert over Clade I. At the time, Rosamund Lewis of the WHO’s monkeypox surveillance team said, “The virus variant is known to be more virulent. If it adapts better to human-to-human transmission, that presents a risk.”

According to the study, the monkeypox strain requires “[u]rgent measures, including reinforced, expanded surveillance, contact tracing, case management support, and targeted vaccination” to “contain this new pandemic-potential Clade Ib outbreak.”

Between September 20, 2023, and February 29, 2024, 241 suspected cases were recorded. Scientists collected 119 samples for PCR testing, finding that 108 individuals tested positive for the virus.

Most of the infected individuals were women (51%), while children under the age of 15 comprised 14.8% of the cases. Those between the ages of 15-30 comprised 28.7% of the confirmed cases and 29.5% of cases occurred among sex workers.

Despite claiming the virus has “pandemic-potential,” most monkeypox cases spread through “sexual contact,” the study noted, noting that such contact is a “key mode of infection.”

“Without intervention, this localized Kamituga outbreak harbors the potential to spread nationally and internationally,” the authors wrote, adding, “Given the recent history of mpox outbreaks in DRC, we advocate for swift action by endemic countries and the international community to avert another global mpox outbreak.”