The UK Health Security Agency has identified a new strain of a potentially ‘severe’ virus
Scientists have warned that the discovery of a new strain of the mpox virus is ‘precisely what experts in the field feared would happen’. The UK Health Security Agency (UKHSA) said the new ‘hybrid’ strain was identified in an individual who had recently travelled to Asia.
Officials at the UKHSA said the World Health Organisation (WHO) has been updated on the finding after tests showed the virus is a ‘recombinant’ strain, meaning it contains genetic material from two different mpox clades that are currently circulating globally.
Mpox, previously known as monkeypox, is a viral infection caused by a virus that belongs to the same family as smallpox. The infection is most commonly found in parts of central and east Africa, but a global outbreak in 2022 caused cases to spike across the globe.
The spread of the clade Ib variant led to heightened surveillance of mpox. In August 2024, the World Health Organization (WHO) declared it a global health emergency.
According to Dr Boghuma Titanji, Assistant Professor of Medicine, Emory University, the new strain found to contain elements of both clade I and clade II mpox is “precisely what experts in the field feared would happen if the virus continued to spread globally without a decisive response to stop it”.
Mpox is part of a family of viruses well known for their ability to ‘recombine to generate new variants’, says Dr Titanji.
She added: “The key concern now is whether events like this will alter the virus’s transmissibility or virulence. There are also implications for how well existing testing platforms can identify these emerging recombinant strains.
“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.”
The UKHSA said it is now assessing the significance of this finding and whether the new strain could behave differently.
Dr Katy Sinka, Head of Sexually Transmitted Infections at UKHSA, said: “Our genomic testing has enabled us to detect this new mpox strain. It’s normal for viruses to evolve, and further analysis will help us understand more about how mpox is changing.
“Although mpox infection is mild for many, it can be severe. 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.
“It is important to remain alert to the risks from this unpleasant illness. Anyone who thinks they may have mpox should contact NHS 111 for advice on what to do.”
The UK has a routine mpox vaccination programme in place for eligible groups, including those who have multiple sexual partners, have group sex and visit sex-on-premises venues.
Studies have shown the vaccine is around 75-80 per cent effective in protecting against mpox, the UKHSA said.
Common symptoms of mpox include a skin rash or pus-filled lesions which can last 2 to 4 weeks. It can also cause fever, headaches, muscle aches, back pain, low energy and swollen lymph nodes.
