recombinant MPXV
A recombinant monkeypox virus carrying genetic material from both clade Ib and clade IIb lineages, first detected in a UK traveller in December 2025 and now found in at least four countries; transmissibility relative to parent strains is undetermined.
Last refreshed: 24 May 2026 · Appears in 1 active topic
Does a monkeypox strain mixing two lineages mean a more dangerous virus is emerging?
Timeline for recombinant MPXV
Mpox strain mixes genes from two clades
Pandemics and Biosecurity- Is the new mixed mpox strain more dangerous than previous ones?
- WHO says it is too early to draw conclusions. No serious complications have been reported in patients carrying the recombinant strain, and genetic recombination alone does not indicate increased danger.Source: WHO Disease Outbreak News 595
- What does it mean when two mpox lineages mix their genes?
- Genetic recombination occurs when two viral lineages infect the same host cell. It is a known feature of poxvirus biology and does not automatically produce a more transmissible or severe virus; the effects depend on which genes are exchanged.Source: WHO / virology literature
- Where was the recombinant mpox virus first found?
- It was first detected in a UK traveller in December 2025, though retrospective analysis identified an earlier case in India from September 2025.Source: WHO Disease Outbreak News 595
- Should I be worried about the mpox recombinant strain?
- WHO treats it as a routine surveillance watch item, not a cause for alarm. No serious complications have been seen in identified patients, and intensified sequencing is under way to track whether the strain behaves differently from known lineages.Source: WHO Disease Outbreak News 595
Background
In May 2026, WHO reported a recombinant monkeypox (mpox) virus sample that carries genetic elements from both clade Ib and clade IIb, two distinct mpox lineages. The sample was first detected in a UK traveller in December 2025 and identified retrospectively in India from September 2025; it has since been found in at least four countries across three WHO regions. WHO has stated it is too early to draw conclusions about transmissibility or severity, and reports no serious complications in identified patients. Surveillance and sequencing are being intensified as a precaution.
Genetic recombination in mpox viruses is a known phenomenon that occurs when two different viral lineages infect the same host cell simultaneously. It does not automatically indicate a more dangerous or transmissible virus; the biological consequences depend on which genetic segments are exchanged and how they interact. Clade Ib, which caused a significant outbreak in eastern DRC and neighbouring countries from 2023, and clade IIb, which drove the global 2022 mpox outbreak, were circulating in regions where co-infection was possible, making recombination an expected feature of routine genomic surveillance rather than an anomaly.
The WHO Disease Outbreak News report that described this finding (DON 595) frames it as a genomic-surveillance watch item, consistent with the scientific consensus that genetic novelty alone does not determine public-health significance. The key questions for ongoing monitoring are whether the recombinant strain demonstrates any change in epidemiological behaviour compared with its parent lineages, something that requires sustained surveillance data over time rather than immediate action.
