On December 8, 2025, the United Kingdom found itself at the forefront of global health news as officials confirmed the discovery of a new recombinant strain of mpox—formerly known as monkeypox—in a traveler recently returned from Asia. According to the UK Health Security Agency (UKHSA), this newly identified strain is a genetic blend, containing elements from two distinct viral lineages: clade Ib and clade IIb. It’s a development that has health authorities on alert, not just in the UK but worldwide, as they work to understand what this means for the ongoing fight against mpox.
The UKHSA was quick to clarify that viruses are, by their very nature, always evolving. Dr. Katy Sinka, head of sexually transmitted infections at the agency, explained, “It’s normal for viruses to evolve, and further analysis will help us understand more about how mpox is changing.” The discovery was made possible through the agency’s advanced genomic sequencing capabilities, which have enabled scientists to detect subtle but significant shifts in the virus’s genetic makeup.
But what exactly is a “recombinant” virus? In this case, it means the mpox strain found in England is a hybrid, carrying genetic material from both clade Ib and clade IIb. Clade Ib has recently shown signs of local spread in Europe and the United States, while clade IIb was responsible for the global mpox outbreak in 2022. The UKHSA has already shared details of the new strain with international partners, including the World Health Organization, to bolster global monitoring efforts.
Although mpox infections are often mild, the disease can be more severe for some people, especially those who are not vaccinated. The symptoms are, frankly, unpleasant: fever, headaches, muscle aches, back pain, low energy, and a rash that can develop into blisters, spots, or ulcers. According to the NHS, the rash typically appears one to five days after the initial fever and flu-like symptoms, and the illness can last anywhere from two to four weeks. Swollen lymph nodes and exhaustion are also common complaints.
Transmission of mpox is primarily through close contact—think direct skin-to-skin interactions, sexual contact, kissing, cuddling, or even prolonged face-to-face conversations. The virus can also spread through contact with bodily fluids such as saliva or nasal mucus, as well as through contaminated clothing, bedding, or towels. In some parts of Africa, animal-to-human transmission remains a concern. While mpox doesn’t spread as easily as some other viruses, these multiple routes of transmission underscore why health officials are paying such close attention to any new developments.
For those worried about their risk, the UK has a vaccination program targeting groups deemed at higher risk of exposure. This includes people with multiple sexual partners, those who participate in group sex, and visitors to sex-on-premises venues. Studies have shown the vaccine to be 75–80% effective against mpox, offering significant protection against severe illness. Dr. Sinka urges those eligible not to hesitate: “Getting vaccinated is a proven effective way to protect yourself against severe disease, so please make sure to get the jab if you are eligible.” Vaccinations can be arranged through sexual health clinics, and a large proportion of eligible individuals in the UK have already received the jab.
Still, the emergence of this recombinant strain has raised important questions about the future of the virus. Dr. Boghuma Titanji, assistant professor of medicine at Emory University in Georgia, voiced concerns that echo throughout the scientific community: “The identification of a recombinant mpox strain containing elements of both Clade I and Clade II is precisely what experts in the field feared would happen if the virus continued to spread globally without a decisive response to stop it. The key concern now is whether events like this will alter the virus’s transmissibility or virulence.”
Professor Trudie Lang, director of the Global Health Network at the University of Oxford, also highlighted the challenges that come with tracking and containing mpox, especially in regions where healthcare infrastructure is less robust and access to vaccines is limited. “It is of concern that there is an mpox case in the UK, and of further concern that it is a new recombinant mpox virus. This case highlights that mpox is circulating globally and is evolving, as is predictable with these viruses,” she noted. Lang emphasized the need for a connected global effort to monitor transmission routes and severity, especially if more cases of this recombinant strain emerge.
Globally, mpox has remained a persistent threat. In 2025 alone, nearly 48,000 cases were confirmed, with 2,500 reported just in the past month—most of them in central Africa. The Democratic Republic of the Congo, in particular, has suffered extensive outbreaks linked to the more severe clade I, which has caused numerous deaths. In contrast, clade II was responsible for the 2022 outbreak in the United States and is rarely fatal, though it continues to circulate at lower levels.
The recombinant strain detected in England is currently believed to be a one-off case, but health officials remain cautious. The UKHSA has said it will “continue to assess the significance of the strain” as more data becomes available. For now, the focus remains on vaccination, vigilant monitoring, and clear public communication. Anyone who suspects they may have mpox is advised to contact NHS 111 for guidance on what to do next.
Experts warn that the continued global circulation of mpox increases the likelihood of further genetic recombination and adaptation, potentially making the virus more entrenched in human populations. As Dr. Titanji put it, “The more mpox circulation we permit, the more opportunities the virus has to recombine and adapt, further entrenching mpox virus as a human pathogen that is not going away.”
While the world has faced down many viral threats before, the discovery of this new strain of mpox serves as a reminder that vigilance, scientific collaboration, and public health preparedness remain as crucial as ever. With ongoing research, robust vaccination programs, and international cooperation, health officials hope to stay one step ahead of the virus—even as it continues to evolve in ways both predictable and surprising.
