As concerns mount about a type of mpox spreading across Africa that’s believed to cause more serious illness, infectious disease experts expressed cautious optimism that this branch of the virus would not spread as broadly in the U.S. or cause health impacts as severe.

The risk of this subtype of mpox to the U.S. could be mitigated by a number of factors, including immunity from vaccination and previous infection from the outbreak of a different variant that began in 2022; the lack of viral…