#19,136
While details were scant, just short of 5 months ago (Dec 8th) the UKHSA Identified a New Recombinant Strain of Mpox Virus in a traveler recently returning from an (undisclosed) country in South-East Asia.
For the very first time, genomic sequencing showed an emerging mpox strain with elements from both clade Ib and IIb mpox.
Two months later the WHO announced a 2nd case, describing the two cases as:
The first case was detected in the United Kingdom of Great Britain and Northern Ireland (hereafter “United Kingdom”), with travel history to a country in South-East Asia, and the second in India, with travel history to a country in the Arabian Peninsula.Detailed analysis of the virus genomes shows that the two individuals fell ill several weeks apart with the same recombinant strain, suggesting that there may be further cases than are currently reported. Both cases had similar clinical presentation to that observed for other clades. Neither patient experienced severe outcomes. Contact tracing for both cases in the reporting countries has been completed; no secondary cases were detected.
With little fanfare, 72 hours ago the WHO announced the third detection of a recombinant strain in their latest SitRep (#65), although they buried the lede somewhat, putting the first mention at the very bottom of their list of highlights.
Highlights
• Transmission of mpox continues mostly within sexual networks, affecting men and women, often followed by household transmission and, in some areas, affecting all age groups. All clades of monkeypox virus (MPXV)continue to circulate. Rapid containment of mpox outbreaks is essential to prevent community transmission in any setting.
• In March 2026, 48 countries across all WHO regions reported a total of 1235 confirmed mpox cases, including five deaths (case fatality ratio [CFR] 0.4%). Of these cases, 70.4% were reported in the WHO African Region.
• Four WHO regions – the Region of the Americas, African, European, and South-East Asian regions – reported a decline in confirmed cases in March, compared to February 2026, while the Eastern Mediterranean and Western Pacific Region reported an increase in confirmed cases.
• Sixteen countries in Africa reported active transmission of mpox in the last six weeks (9 March – 19 April 2026),with 969 confirmed cases, including three deaths (CFR 0.3%). Madagascar, the Democratic Republic of the Congo,Guinea, Kenya, and Burundi reported the highest number of cases during this period.
• Four countries, Colombia, Denmark, Ecuador and Singapore, reported mpox due to clade Ib MPXV for the first time. Poland and Slovakia reported mpox due to clade I MPXV for the first time, pending subclade identification.
• Outside Africa, Argentina, Denmark, Germany, Pakistan, Portugal, Singapore, Spain, and the United Kingdom of Great Britain and Northern Ireland reported community transmission of clade Ib MPXV, including among men who have sex with men.
• Pakistan has reported a healthcare-associated mpox outbreak in Sindh province, involving neonates, infants, and adults. In the past month, the province has reported 29 confirmed cases, including eight deaths (case fatality ratio: 28%), and one additional death in a suspected case. About half of cases, and all deaths were reported among infants younger than six months of age.
• Qatar has reported a travel-related case of mpox with a clade Ib/IIb recombinant MPXV strain, the third such reported case globally, following previous case reports in India and the United Kingdom of Great Britain and Northern Ireland. The patient has recovered and no secondary cases have been reported to date.
While there is admittedly a lot going on in the world right now, this latest case appears to have escaped the notice of the mainstream press. The WHO report goes on to state (on page 8):
Detection of recombinant MPXV strain in Qatar
On 24 March 2026, Qatar notified WHO of a laboratory-confirmed mpox case infected with a recombinant MPXVstrain containing genomic elements of clade Ib and IIb MPXV. The case is an adult male resident in Qatar, who developed general and genital mpox symptoms on 10 March and was confirmed to have mpox on 21 March.
Genomic sequencing on 2 April confirmed infection with a recombinant clade Ib/IIb MPXV strain.
The individual reported short travel to Saudi Arabia during the incubation period, but no contact with a known mpox case. He did not report any sexual or other known high-risk exposures in either Saudi Arabia or Qatar, and to date, the source of infection for this case remains unknown. Following the initial diagnosis, the case was isolated in a facility and recovered fully.
Contact tracing was completed with no secondary cases identified.
This represents the third known detection of this MPXV recombinant strain globally, following travel-related detections in India and the United Kingdom of Great Britain and Northern Ireland. Consistent with previous detections, no differences in clinical presentation have been observed compared with infection with non-recombinant MPXV strains.
While the public health risk associated with this event in Qatar and globally is assessed as low, it highlights the potential for undetected spread of this recombinant strain and the risk of continued emergence of recombinant strains in the context of co-circulation of multiple MPXV clades. Ongoing surveillance, genomic sequencing, and case investigation remain critical.
Previously the WHO reported on the first 2 cases:
Detailed analysis of the virus genomes shows that the two individuals fell ill several weeks apart with the same recombinant strain, suggesting that there may be further cases than are currently reported.
But that same report, also said:
After classification of this case and posting in a public database as a novel MPXV recombinant strain, a case of mpox detected in India in September 2025 was retrospectively reclassified as a closely-related recombinant strain based on sequencing data.
This latest report states - `This represents the third known detection of this MPXV recombinant strain globally. . . ' - which strongly suggests all 3 recombinants are genetically similar.
As recently as 5 years ago, there were only 2 recognized clades of Mpox (then Monkeypox): The milder West African (now clade IIa) and the more severe Central African clade (now Clade Ia).But without more detailed information, it is difficult to say whether all 3 cases stem from a single recombination event.
But like all viruses, Mpox continues to evolve and diversify, as discussed in the 2014 EID Journal article Genomic Variability of Monkeypox Virus among Humans, Democratic Republic of the Congo, where the authors cautioned:
Small genetic changes could favor adaptation to a human host, and this potential is greatest for pathogens with moderate transmission rates (such as MPXV) (40). The ability to spread rapidly and efficiently from human to human could enhance spread by travelers to new regions.
In recent years we've seen an explosion in the number of Mpox strains, with multiple lineages of clade IIb spreading globally in 2022 - followed in 2023 by the emergence of a new clade Ib, which is slowing spreading internationally as well.
The detection of 3 (reportedly similar) recombinant strains in 3 different countries raises the possibility that a new - genetically distinct strain - may be emerging.
While RT-PCR can detect this recombinant a Mpox positive, it doesn't flag it as being `different'. For that, WGS (Whole Gene Sequencing) is needed, and sadly, only a small fraction of samples are sequenced.
Which means it may be some time before we know if these 3 cases are merely a flash in the pan, or a stronger, more worrisome, signal. But as Ian Fleming once famously wrote;
"Once is happenstance, twice is coincidence, three times is enemy action"
So we'll be watching this evolving situation closely.
