UK health officials warn of new mpox variant
December 8, 2025
The detection of a recombinant mpox strain in England underscores the virus’s ongoing evolution and the importance of robust genomic surveillance. The new hybrid, containing elements of clade 1b and 11b, was identified in a traveler returning from Asia, illustrating how global mobility continues to shape viral spread. While the UK Health Security Agency has emphasized that evolution is expected, the development coincides with the World Health Organization’s alert of clade 1b community transmission in multiple non-endemic countries. This convergence highlights the need for continued vigilance, equitable vaccination access, and rapid sequencing to prevent another wave of global mpox transmission.
The identification of a recombinant mpox strain in England marks a significant development in the virus’s ongoing evolution. Detected in an individual who had recently traveled to Asia, genomic sequencing by the UK Health Security Agency revealed that the virus contains elements of both clade 1b and 11b. Clade 1b, first identified in the Democratic Republic of the Congo in 2024, is known for higher transmissibility and virulence, while clade 11b drove the 2022 global outbreak primarily among men who have sex with men (MSM). The combination raises new concerns about how the virus may adapt and spread.
According to UKHSA officials, viral evolution is expected, but the discovery underscores the value of advanced genomic monitoring to detect mutations early. Authorities reaffirmed that vaccination remains the best defense, particularly for at-risk groups such as MSM and individuals with multiple sexual partners.
The World Health Organization has also sounded the alarm on broader community transmission of clade 1b outside Africa. Forty-three confirmed infections have been reported across six WHO regions in individuals without recent travel history, including locally acquired cases in the United States. WHO now classifies countries such as Italy, Malaysia, the Netherlands, Portugal, Spain, and the United States as experiencing community transmission.
While the risk to the general population remains low, the spread of a more virulent strain into new regions represents a troubling shift in the mpox landscape. Global coordination on surveillance, vaccination, and communication is critical to mitigating this emerging threat. The new recombinant strain, arising as Africa continues to report most global cases, serves as a reminder that outbreaks anywhere remain a collective risk everywhere. Sustained international monitoring, equitable vaccine distribution, and rapid data sharing will be essential to prevent another resurgence of mpox.