Though the surge in Sierra Leone has received much of the attention, cases are also rising in two other countries in West Africa: Ghana and Liberia.
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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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.
So far this year Brazil has reported 52 cases of mpox, but all were clade 2.
In other developments, the recently identified clade 1a virus that has the APOBEC3 mutation, linked to more transmissibility, has been reported from Kinshasa.
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.
