No secondary cases were discovered following contact tracing.
The WHO has published a detailed update on the two cases and national responses.
Recombination is a natural process this can happen when two related viruses infect the same person and exchange genetic material, creating a new variant.
According to the WHO, detailed genomic analysis shows that the two individuals “fell ill with the same recombinant strain several weeks apart,” suggesting that additional undetected cases may exist.
What is mpox?
Mpox is an infectious disease caused by monkeypox virus (MPXV), part of the genus Orthopoxvirus, which also includes the virus that causes smallpox.
It spreads through close physical contact, including sexual contact, and in some cases through contaminated materials or respiratory droplets.
Symptoms typically include fever, swollen lymph nodes, and rashes and/or lesions.
Click here for the WHO fact sheet on mpox.
Two cases detected
The case in Great Britain was discovered in December 2025 in a traveler returning from a country in the Asia-Pacific region. Initial laboratory testing identified the virus as clade Ib, but whole genome sequencing later revealed that it contained genetic regions from both clade Ib and clade IIb strains. Repeated sequencing confirmed the findings and showed that the virus “can replicate and has the potential for onward transmission.”
In Indiaa patient who developed symptoms in September 2025 was initially classified as infected with clade II MPXV. However, following updates to the global genomic databases, the virus was reclassified as the same recombinant strain identified in Britain. The Indian case represents the earliest known detection of this strain.
“Due to the small number of cases identified to date, conclusions regarding the transmissibility or clinical characterization of mpox due to recombinant strains would be premature, and it remains essential to remain vigilant about this development”, said the WHO.
The clinical manifestations in both cases were consistent with known MPOX infections.
Risk assessment unchanged
The WHO’s overall risk assessment remains unchanged: the risk is estimated as moderate for men who have sex with men with new and/or multiple partners and for sex workers or others with multiple casual sexual partners, and low for the general population without specific risk factors.
At the same time, the WHO warned that PCR tests for clade differentiation alone “may not reliably identify recombinant MPXV strains,” meaning genomic sequencing is essential for detection.
“All countries should remain alert to the possibility of genetic recombination of MPXV,” the WHO said, urging continued epidemiological surveillance, sequencing, vaccination of high-risk groups and infection prevention and control measures.
The WHO has advised that no travel or trade restrictions are warranted based on current information.
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