Also, the WHO highlights more local transmission of clade 1b in multiple countries.
The test the US Centers for Disease Control and Prevention uses to identify clade I mpox cases is 'most likely not reliable' for detection of the substrain identified in the study, the authors say.
Another mpox study today showed that dose-sparing vaccine administration of the Jynneos vaccine appeared to have worked.
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Clade 1b is fueling a central Africa mpox outbreak, with the Democratic Republic of the Congo seeing the most cases.
Earlier patients had traveled to outbreak countries or were contacts of earlier cases.
Ghana reported its first recurrence in many weeks, as cases rise in Tanzania and responders launch a second vaccination round in Uganda.
The freeze-dried Jynneos formulation will be easier to store and transport and will have a longer shelf life.
In its monthly mpox update, the WHO said it is tracking several genetic developments, including rising cases of the rare 2b clade.
In mpox outbreak developments, Sierra Leone launched its vaccine drive today as cases in Africa continue to climb.
As African officials look for ways to slow a sharp drop in health assistance, they predict an impact of 2 million to 4 million deaths per year.
Officials said the virus still poses a health threat, with some patients experiencing more severe symptoms.
Vaccinated participants' skin lesions healed faster, and they were less likely to have systemic symptoms.
Outbreak challenges include keeping up with testing in the DRC and rising deaths and overwhelmed treatment centers in parts of Uganda.
