Clinical characteristics and factors contributing to transmission of congenital syphilis in England, 2015–24: a national surveillance study

Background Congenital syphilis has re-emerged in England despite near-universal antenatal screening coverage, indicating that important opportunities for prevention continue to be missed. We aimed to characterise the clinical presentation, diagnostic findings, and factors contributing to transmission among congenital syphilis cases in England to inform strategies for earlier diagnosis and prevention. Methods We reviewed probable and confirmed congenital syphilis cases in England (January 2015 to June 2024) reported through the Integrated Screening Outcomes Surveillance Service, including maternal and infant demographic, clinical, laboratory, treatment, and outcome data. Findings Among 67 cases there were 54 livebirths, including five neonatal deaths, and 13 stillbirths. Common manifestations included hepatosplenomegaly, rash, bone abnormalities, thrombocytopaenia and jaundice. Neonatal IgM was positive in 81% (34/42), whereas only 24% (10/41) of mother–infant pairs demonstrated the expected four-fold higher non-treponemal titre in the infant. PCR was positive in 87% (13/15) of those tested but was used infrequently. Nearly half of cases (32/67, 48%) occurred in infants whose mothers had screened negative antenatally but acquired syphilis during pregnancy. Maternal symptoms were often overlooked, and some infants were initially treated for presumed sepsis without syphilis testing. Other cases were associated with late antenatal booking, incomplete treatment, difficulties engaging with maternity services, and complex social circumstances. Interpretation Congenital syphilis in England remains associated with substantial morbidity and mortality. Maternal infection acquired during pregnancy, missed diagnostic opportunities, and social vulnerability contribute to transmission. Greater clinical vigilance, wider use of PCR, improved engagement with vulnerable women, and consideration of universal third-trimester screening could strengthen prevention efforts. Funding Funding was received from the Sexually Transmitted Infection Research Foundation, United Kingdom.