Will Evolving Mpox Clades Cause Global Outbreaks Again
January 9, 2026
Mpox has faded from headlines, but it has not faded from reality. With sustained transmission in Africa, emerging recombinant strains, and sporadic imported cases elsewhere, the virus continues to evolve under the radar. Evidence summarized in Nature underscores how clade diversity, sexual transmission dynamics, and viral persistence complicate control efforts. The appearance of a recombinant strain and unanswered questions about fertility impacts should sharpen global attention. Surveillance, vaccination of at-risk populations, and continued research are not precautionary luxuries. They are the minimum requirements to prevent mpox from re-emerging as a broader and more adaptive global threat.
Mpox may no longer dominate global news cycles, but recent scientific findings suggest complacency would be a costly mistake. While clade IIb fueled the 2022 global outbreak through efficient sexual transmission, clade I strains, particularly subclade Ib, are now driving more severe outbreaks across Central and East Africa. These parallel dynamics highlight a virus that is not only persisting, but diversifying in ways that challenge current control strategies.
Emerging research led by Alyson Kelvin at the University of Calgary suggests that clade IIb can persist in reproductive tissue in animal models, offering a plausible biological explanation for prolonged sexual transmissibility. While these findings are preliminary and not yet confirmed in humans, they reinforce the need to study mpox beyond acute infection outcomes.
The identification of a recombinant mpox strain in England further underscores the evolutionary risks of sustained transmission. Recombination is not unexpected when multiple clades circulate simultaneously, but it raises legitimate concerns about viral adaptability and the long-term reliability of existing vaccines and therapeutics.
Vaccination remains a critical tool. The JYNNEOS vaccine has demonstrated meaningful protection against clade II strains, with anticipated cross-protection against clade I based on conserved orthopoxvirus proteins. However, empirical data on this protection remain limited. As Boghuma Titanji of Emory University has cautioned, much remains unknown about emerging strains and their potential to entrench themselves in human populations.
Public health agencies, including the Centers for Disease Control and Prevention, are right to emphasize surveillance and targeted vaccination, particularly for travelers and high-risk groups. Mpox is not a closed chapter. It is an evolving story that demands sustained scientific and policy attention before adaptation outpaces preparedness.