Key Points

• From January 1 to May 31, 2026, 201 cases of smallpox B (mpox) were reported, including 7 without laboratory confirmation.
• Among the cases for which the clade could be identified, 68% (67/99) belonged to clade Ib, compared with 32% to clade IIb.
• The reported cases involved 174 men (87%) and 27 women. With the exception of one case in a child (<15 years old), all reported cases were adults with a median age of 34 years. More than one-third resided in Île-de-France (90/198; 45%); 22% resided in the Indian Ocean departments, including 31 in Mayotte and 12 in Réunion.
• In terms of risk exposures, 34% of the documented cases (65/193) reported contact with a case within the 3 weeks prior to the onset of their symptoms; 36% (67/188) had traveled abroad within the 3 weeks prior to the onset of their symptoms (Europe and sub-Saharan Africa). Of the 47 men who reported contact with a case, 35 (74%) involved a sexual partner.
• Among the 191 cases for which this information was available, 21 (11%) were hospitalized, primarily for the management of severe pain (n = 16 cases) or generalized rashes (n = 12 cases).
• Regarding vaccination status when known, 77% (130/168) had not received any vaccine doses since May 2022. Among the 38 vaccinated cases, 15 had received a single dose (including 4 with a history of vaccination prior to 1984), 15 had received two doses, and 3 had received three doses. The number of doses received since 2022 was unknown for 5 cases.