Hybrid of two known clades raises monitoring concerns
Scientists have identified a new mpox strain that contains genetic elements from both clade Ib and clade IIb, creating a recombinant version of the virus that currently has no official name. The discovery comes as public health agencies across Europe report early signs of local transmission of clade Ib, prompting renewed vaccination reminders for gay, bisexual, and other men who have sex with men — groups considered at higher risk of exposure.
Clade IIb was responsible for the global mpox outbreak in 2022, which spread across dozens of countries. The UK continues to offer vaccination to those most at risk, including people with multiple sexual partners, those who attend group sex events, and individuals who visit sex on premises venues. Health officials say available vaccines offer an estimated 75 to 80 percent protection against mpox, though effectiveness against the new recombinant strain has not yet been studied.
Experts urge vaccination as genetic changes emerge
Dr Katy Sinka of the UK Health Security Agency said genomic surveillance enabled rapid detection of the recombinant strain, emphasizing that ongoing viral evolution is expected. She urged eligible groups to remain protected through vaccination, calling it a proven tool for preventing severe disease.
While the UK has robust identification and containment systems, global experts caution that this capacity is uneven worldwide. Professor Trudie Lang of the University of Oxford noted that vulnerable regions, particularly those with limited vaccine access, face greater challenges in tracking and controlling spread. Understanding how the new strain transmits and how severe its symptoms are will be essential if cases increase beyond current levels.
Global spread heightens concerns
Nearly 48,000 mpox cases have been confirmed worldwide in 2025, including 2,500 in the last month alone, with central Africa experiencing the highest burden. Dr Boghuma Titanji of Emory University warned that continued global circulation creates ideal conditions for the virus to recombine and adapt. Each new variant raises the risk of mpox becoming more firmly entrenched as a persistent human pathogen.
Mpox typically causes a rash or lesions lasting two to four weeks, often accompanied by fever, headaches, muscle aches and fatigue. Transmission occurs through close physical contact, contaminated materials, and respiratory droplets. UK health officials advise anyone who suspects they may have mpox to contact NHS 111 for guidance.