The World Health Organization recently confirmed the detection of a newly identified recombinant mpox virus containing genetic material from two distinct strains. This discovery underscores the critical need for global genomic surveillance even though the overall public health risk assessment remains unchanged. To date, officials have identified two cases of this strain, which combines genomic elements from clades Ib and IIb.
WHO has published a detailed update on the two cases and the national responses.
These cases appeared in the United Kingdom and India, involving patients who recently traveled but did not experience severe illness. Moreover, health authorities conducted extensive contact tracing and found no secondary cases following these initial detections in either country.
Tracking the Two Detected Cases
The case in the United Kingdom was detected in December 2025 in a traveler returning from the Asia Pacific. While initial tests identified the virus as clade Ib, whole genome sequencing later revealed genetic regions from both known strains.
Furthermore, repeat sequencing demonstrated that this recombinant virus can replicate and presents a clear potential for onward viral transmission. Meanwhile, a patient in India developed symptoms in September 2025 and was initially classified as having a standard infection. However, recent updates to global genomic databases allowed scientists to reclassify this as the earliest known recombinant strain detection.
Understanding Recombination and Risk
Recombination occurs naturally when two related viruses infect the same person and exchange genetic material to produce a new variant. Additionally, the World Health Organization warns that standard PCR tests might not reliably identify these specific recombinant mpox strains. Therefore, countries must prioritize whole genome sequencing to ensure they can accurately detect and track these new viral developments.
Despite this discovery, the global public health risk remains moderate for high-risk groups and low for the general population. WHO continues to monitor these developments closely to determine if transmissibility or clinical characteristics change in the near future.
WHO Recommendations for Global Vigilance
The WHO continues to advise that no travel or trade restrictions are warranted based on the information available today. Instead, all countries should remain alert by maintaining epidemiological surveillance and providing vaccinations for those in at-risk groups. Furthermore, implementing strong infection prevention and control measures is essential for managing the spread of any emerging mpox variants. Ultimately, maintaining international vigilance regarding these recombinant strains is vital for protecting public health and preventing future outbreaks. Scientists suggest that additional undetected cases may already exist because the two identified individuals fell ill several weeks apart.
Q&A: The New Recombinant Mpox Strain
Q: What exactly is a recombinant virus?
A: It is a new variant created when two related viruses infect one person and exchange their genetic material naturally.
Q: Where were the first cases of this new mpox strain found?
A: Officials identified the first two cases in the United Kingdom and India, both involving patients with recent travel histories.
Q: Can standard medical tests detect this new version of mpox?
A: Standard PCR tests may not reliably identify recombinant strains, so scientists must use advanced genomic sequencing for accurate detection.
FAQ
Is the general public at high risk from this new strain?
No, the WHO assesses the risk as low for the general population without specific risk factors at this time.
Are there new travel restrictions because of this discovery?
The World Health Organization currently advises that no travel or trade restrictions are necessary based on the current data.
Which mpox clades are combined in this recombinant virus?
This specific recombinant strain combines genomic elements from clade Ib and clade IIb of the monkeypox virus (MPXV).
When was the earliest case of this strain detected?
The earliest known detection occurred in India in September 2025, although it was only recently reclassified as recombinant.
What should countries do to prepare for this virus?
Nations should maintain alert surveillance, increase genomic sequencing, and ensure at-risk groups have access to necessary vaccinations and care.