Worrying increase in the risk of vertical transmission of syphilis in Croatia, 2020 to 2024.

Four infants potentially exposed to syphilis infection in utero, meeting World Health Organization surveillance criteria of congenital syphilis (CS), were diagnosed in Croatia between September 2020 and January 2024. We conducted a retrospective analysis of epidemiological, clinical and laboratory data of these cases to assess compliance with surveillance case definitions. As only one confirmed CS case has been reported in Croatia in over 2 decades, these reports signal an increased risk of syphilis vertical transmission and warrant strengthening antenatal screening.