The infected person exposed 17 people at 2 group homes to the disease.
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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Over the weekend South Africa said it now has 22 cases of the virus.
Some of the cases have been caused by what researchers are calling "clade 1b," a new mpox lineage identified in the DR Congo last year that is highly transmissible.
The trial will also assess if vaccinated individuals who contract mpox have more mild courses of illness.
The team arrived at 6 target pathogens: the viruses that cause polio, influenza A, influenza B, mpox, COVID-19, and measles.
South Africa is experiencing its first spike in clade 2 mpox detections since 2022, and outbreak findings suggest ongoing community spread.
If the country can tap vaccine donations, the tool could help the country battle its surge in novel clade 1 cases.
South Africa has identified 6 new mpox cases in an outbreak that began in late May.
Thirty-nine percent of all California mpox cases occurred in Los Angeles County.
Illnesses have now been reported in 23 of the country's 26 provinces, with the virus causing the heaviest burden in children.
Though data reflect ongoing low-level transmission in multiple regions, the WHO said reduced reporting may underestimate illness levels.
