recombinant MPXV

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.