When a traveller returning from Asia Pacific landed in the UK in December 2025, routine genomic sequencing flagged something unexpected: a mpox virus carrying genetic material from two different lineages. UK health officials quickly confirmed the find, but also moved to reassure the public. Here is what we know so far.
Confirmed cases: 1 clade Ib recombinant in England · Risk level: Low to UK population · Strain type: Recombinant clade Ib + IIb · Detection date: December 2025 · Agency: UKHSA
Quick snapshot
- First clade Ib/IIb recombinant case detected in UK (WHO Disease Outbreak News)
- Patient had recent travel to South-East Asia (UN News)
- Two recombinant cases known globally: UK and India (WHO Disease Outbreak News)
- UK case detected December 2025, India case September 2025 (earliest known) (WHO Disease Outbreak News)
- Community transmission outside Africa confirmed from October 2025 (WHO Disease Outbreak News)
- UK importation risk rose from medium to high by October 2025 (WHO Disease Outbreak News)
- UKHSA continues phenotypic characterisation studies (WHO Disease Outbreak News)
- Ongoing genomic surveillance across UK and globally (WHO Disease Outbreak News)
- Vaccines remain effective against the recombinant strain (WHO Disease Outbreak News)
The table below summarises the key facts surrounding the recombinant mpox case confirmed by UKHSA.
| Field | Value |
|---|---|
| Strain | Clade Ib recombinant |
| Location | England, UK |
| Cases | 1 confirmed recombinant; 45 total clade Ib UK-wide as of 31 March 2026 |
| Risk | Low to UK population |
| Agency | UK Health Security Agency (UKHSA) |
| Travel link | Asia Pacific region |
Is there a new strain of mpox?
Yes. UKHSA confirmed the first case of a recombinant mpox virus in England in December 2025, detected in a traveller returning from an Asia Pacific country. The virus combines genetic material from both clade Ib and clade IIb strains, marking a notable shift in the virus’s molecular profile.
Clade Ib detection in England
Whole genome sequencing revealed the recombinant nature of the case, with genetic regions from both lineages. The UK case was initially flagged as clade Ib but later confirmed to harbour elements of clade IIb as well. Repeat sequencing confirmed the findings, demonstrating the virus can replicate and presents potential for onward transmission.
Recombinant elements from Ib and IIb
WHO confirmed that two cases of this recombinant strain have been identified globally as of early 2026: one in the United Kingdom and one in India. The India case, detected in September 2025, was retrospectively reclassified as the same recombinant strain, making it the earliest known detection. Both patients had recent travel histories, and neither experienced severe illness.
The recombinant virus is not a brand-new pathogen — it is a reassortment of strains already known to science. Scientists can track its origins through genomic sequencing, but they cannot yet say how long it has been circulating or whether it will spread differently than its parent lineages.
Is mpox spreading in the UK?
Beyond the single recombinant case, UKHSA has tracked a broader rise in clade Ib mpox cases across the country. Up to 31 March 2026, 45 cases of clade Ib mpox had been reported in the UK: 39 in England, 3 in Scotland, and 3 in Wales, with Northern Ireland reporting zero cases.
Current case count
Most of the 45 UK clade Ib cases reported up to 31 March 2026 have links to travel to countries where the strain is circulating. Recent increases have been seen in London and the North West of England, with infections predominantly occurring in known risk groups. A small number of contacts were identified and followed up following the recombinant case; none developed clinical features of mpox.
Epidemiological overview
The epidemiology of clade Ib mpox has shifted. Person-to-person transmission is now occurring outside the African Region, including amongst gay, bisexual and other men who have sex with men networks in at least two other WHO regions since October 2025. In that month, health authorities in Spain, USA (California), Netherlands, Italy and Portugal reported locally-acquired clade Ib cases with no travel history or links to confirmed cases.
The importation risk for clade I mpox into the UK rose from medium to high by October 2025. The shift from travel-linked cases to community transmission marks a different kind of threat — one that requires sustained surveillance rather than border controls alone.
Should we be worried about the new mpox strain?
UKHSA has consistently maintained that the risk to the UK population remains low following the clade Ib cases. The overall global public health risk assessment for the recombinant strain, according to WHO, also remains unchanged.
Risk assessment
The recombinant strain carries genetic material from two established lineages, but neither patient in the UK or India experienced severe illness. Vaccines remain effective against the recombinant mpox virus identified in England, according to analysis from EMJ Reviews. Health worker contacts in the UK case had worn full PPE during provision of medical care, further reducing transmission risk.
Comparison to prior strains
It is not possible to determine from a single genome how long the recombinant virus has been in circulation, or whether it will hold a fitness benefit over currently circulating lineages. The detection of this newly identified recombinant mpox virus underscores the need for continued genomic surveillance, according to WHO.
Detailed analysis of the UK and India recombinant case genomes shows the two individuals fell ill several weeks apart with the same strain. This gap raises the possibility that further undetected cases exist, making broad testing and reporting critical.
What are the symptoms of the new mpox strain England?
Mpox, formerly known as monkeypox, primarily targets the skin and lymph nodes. The characteristic symptom is a rash that can appear anywhere on the body, often starting with flat red marks that develop into raised bumps, fluid-filled blisters, and eventually scabs.
Rash and other signs
The rash associated with mpox is sometimes described colloquially as a “rash virus” given its prominent visibility. Alongside the rash, individuals may experience fever, headache, muscle aches, swollen lymph nodes, and exhaustion. The illness typically lasts two to four weeks.
Targeted organs
Monkeypox targets the skin and lymph nodes as its primary sites of interaction with the human body. The virus causes lesions that can affect the face, hands, feet, chest, and genitals. Severe cases may involve lesions in the mouth, eyes, or rectum.
Is there a strain of mpox in the UK?
Yes. England has recorded a clade Ib/IIb recombinant case and, more broadly, 39 confirmed clade Ib cases as of 31 March 2026. The first UK case was detected in Leeds on 29 November 2024, followed by East Sussex on 20 January 2025 and London on 13 February 2025, all in individuals returning from Uganda.
Recent identifications
The recombinant case stands apart from the broader clade Ib cluster. While most clade Ib cases have travel links to countries in Africa where the strain circulates, the recombinant patient had travelled to South-East Asia — a different geographical source entirely.
UK vs global cases
Globally, clade Ib has been detected in Belgium, Canada, France, Germany, Sweden and the United States. The recombinant strain has so far been confirmed in only two countries: the United Kingdom and India. WHO continues to urge member states to maintain surveillance and report unusual clusters.
Timeline of events
The chronology below tracks key milestones from the first UK clade Ib detection through to the recombinant strain confirmation.
| Date | Event |
|---|---|
| September 2023 | An epidemic of clade I mpox began in Central Africa |
| 29 November 2024 | First clade Ib case detected in Leeds, UK (GOV.UK – UKHSA) |
| 20 January 2025 | Case detected in East Sussex, UK (GOV.UK – UKHSA) |
| 13 February 2025 | Case detected in London, UK (GOV.UK – UKHSA) |
| October 2025 | Community transmission of clade Ib confirmed outside Africa (Travel Health Pro) |
| September 2025 | India detects recombinant clade Ib/IIb case (earliest known) (WHO) |
| December 2025 | UK detects first recombinant clade Ib/IIb case (WHO) |
| 14 February 2026 | WHO notes recombinant strain in UK and India (WHO) |
| 31 March 2026 | 45 total clade Ib cases in UK: 39 England, 3 Scotland, 3 Wales (GOV.UK – UKHSA) |
Confirmed facts
- Single recombinant case detected in England, December 2025
- Strain combines genetic elements of clades Ib and IIb
- 45 total clade Ib cases in UK as of 31 March 2026
- Risk to UK population remains low
- Vaccines remain effective against the strain
What’s unclear
- Strain has no formal scientific name
- Unknown how long recombinant has been circulating
- Unclear whether it holds fitness advantage over other lineages
- Potential for undetected spread remains
The risk to the UK population remains low following the sixth case of clade Ib mpox.
— UK Health Security Agency (UKHSA) official statement
The detection of the newly identified recombinant mpox virus underscores the need for continued genomic surveillance.
— World Health Organization Disease Outbreak News, February 2026
The discovery of a recombinant mpox strain in England carries implications that extend beyond a single case. The fact that two patients in different countries fell ill weeks apart with the same genetic patchwork — and that neither had severe outcomes — suggests the strain is not necessarily more dangerous than existing ones. However, the gap between detections raises the uncomfortable possibility that cases are going unreported, which would blunt the accuracy of every risk calculation officials make.
What is clearer is the response infrastructure. UKHSA has the sequencing capacity to identify recombinants, the contact-tracing protocols to limit spread, and the vaccine stockpile to protect those at highest risk. The limiting factor is not capability but vigilance: as community transmission takes root in more regions, the pressure on surveillance systems grows.
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gov.uk, gov.uk, emjreviews.com, ukhsa-dashboard.data.gov.uk, gov.uk, travelhealthpro.org.uk, cptv.org.uk, cidrap.umn.edu, en.wikipedia.org
UKHSA’s confirmation of England’s first Clade Ib mpox case underscores Clade Ib cases and UK response while affirming low population risk and vaccine effectiveness.
Frequently asked questions
What organ does monkeypox target?
Monkeypox primarily targets the skin and lymph nodes. The characteristic rash and associated swollen lymph nodes are the most visible signs of infection.
Can mpox be killed by alcohol?
Mpox viruses, like other enveloped viruses, are susceptible to standard disinfectants including alcohol-based products (at least 60% concentration). Hand hygiene with alcohol rub is effective when soap and water are not available.
What is clade I mpox?
Clade I mpox is one of two main genetic clades of the mpox virus (the other being clade II). Clade Ib, a subgroup of clade I, has been associated with the more severe epidemic that emerged in Central Africa from September 2023.
How can mpox be prevented?
Prevention measures include vaccination for high-risk groups, avoiding close contact with individuals who have symptoms, practising good hand hygiene, and using appropriate PPE when caring for suspected cases. UKHSA advises that risk to short-term travellers remains low.
Is mpox the same as monkeypox?
Yes, the name was updated by WHO in 2022 to mpox. The virus is the same, but the new name was adopted to reduce stigma and confusion associated with the original term.
What is the current mpox situation in the UK?
As of 31 March 2026, the UK has reported 45 cases of clade Ib mpox, predominantly in England (39 cases). One case involving a recombinant clade Ib/IIb strain was detected in December 2025. UKHSA maintains that risk to the general population remains low.
Are there vaccines for the new strain?
Yes. Existing vaccines remain effective against the recombinant mpox strain identified in England. Vaccination programmes in the UK continue to target high-risk groups.
Freddie Harry Cooper Bennett is a staff writer for DailyPressUK.co.uk, covering UK news, politics, business and culture. He works under Editor-in-Chief Jonathan Whitmore and UK Managing Editor Eleanor Grant, following the newsroom standards for sourcing, verification and fact-checking set out in our editorial policies.