Outbreak challenges include keeping up with testing in the DRC and rising deaths and overwhelmed treatment centers in parts of Uganda.
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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The new clade 1a variant raises significant public health concerns because of its higher transmissibility and morbidity.
An ongoing crisis in South Kivu Province in the DRC has forced at least 400 mpox patients to flee treatment centers.
Experts say the move is very concerning for public health, particularly amid the growing measles outbreak in neighboring Texas.
Officials with Africa CDC said the USAID funding freeze is disrupting the transport of samples from suspected cases to labs.
Only 16% of 670 patients seen at Kamituga hospital in South Kivu were under the age of 15 years.
Fighting has upended lab testing and sent mpox patients fleeing from treatment centers back into the community.
Like other recent cases, the patient had traveled to Uganda, one of Africa's clade 1b mpox hot spots.
Among confirmed cases in the DRC, children 15 years and younger account for 49% of cases.
Though the current African outbreak also features sexual transmission, household transmission is also taking place at a high rate.
In other developments, the WHO says violence in the eastern DR Congo complicates the country's mpox response and that Azerbaijan has reported its first case.