This post has been updated to include new sequences, new analysis, and revised estimates. Background Sierra Leone confirmed its first Mpox case on January 10, 2025, with the Minister of Health declaring a Public Health Emergency shortly thereafter. Cases have surged in recent weeks, with over 2,800 new infections reported as of May 22, 2025, strongly indicating ongoing human-to-human transmission similar to patterns observed in the early stages of the ongoing outbreaks in Nigeria and the DRC ...
