New mpox variant can spread rapidly across borders
February 20, 2025
The rapid evolution of the mpox virus in the Democratic Republic of the Congo (DRC) has sparked global concern as the newly identified clade 1b variant shows increased transmissibility and has spread beyond borders to countries like Sweden and Thailand. Research published in Nature Medicine highlights that clade 1b, first detected in September 2023, now includes three subvariants and poses heightened risks, including increased miscarriages among pregnant women. The virus is spreading primarily through heterosexual contact in densely populated areas, affecting men, women, healthcare workers, and children. Experts urge immediate cross-border cooperation, expanded vaccination, and public education to prevent a wider global outbreak.
The mpox outbreak in the Democratic Republic of the Congo (DRC) has taken a concerning turn as scientists confirm that the virus has mutated into a more transmissible variant, clade 1b. First identified in Kamituga in September 2023, clade 1b has since evolved into three subvariants, enabling faster human-to-human transmission. New research published in Nature Medicine warns of its potential for rapid cross-border spread, with cases already detected in Sweden, Thailand, and neighboring African nations like Burundi.
Unlike previous mpox strains, clade 1b affects both men and women, with infections increasingly linked to heterosexual contact, especially among sex workers in densely populated urban areas. Alarmingly, the virus has also been found in children and healthcare workers, signaling an expanding at-risk population. Genetic analysis of 670 patients revealed that 52.4% of infections were in women, and a striking 57% of pregnant women with mpox suffered miscarriages, raising grave concerns about the virus’s impact on maternal health.
The outbreak has been exacerbated by underreporting and the DRC’s fragile healthcare system. With over 9,500 confirmed cases and a 3.4% fatality rate as of January 2025, local health facilities struggle to manage the crisis. Researchers warn that without immediate global action—including expanded vaccination efforts, travel advisories, and public health education—the virus could spread more broadly.
The GREAT-LIFE project, led by DTU National Food Institute, has been instrumental in identifying the new variant and developing PCR tests for clade 1b detection. However, experts stress that coordinated international efforts are essential to prevent a wider epidemic.
The clade 1b mpox variant has transformed what was once a localized zoonotic threat into a rapidly evolving public health crisis. Urgent intervention is required to contain its spread and safeguard global health security.