US health authorities warned Thursday that a deadlier version of mpox (formerly monkeypox) spreading in the Democratic Republic of the Congo could soon cross international borders, urging those at risk to get vaccinated.
Evidence from past outbreaks indicates that this strain, called clade I, is more lethal than the separate strain that sparked the 2022 outbreak. Clade I has for decades caused small outbreaks, often limited to a few households or communities, in Central Africa. Sexually acquired clade I infections had not been reported before last year.