Gaps in the prevention of mother-to-child transmission of syphilis: a review of reported cases, South Africa, January 2020-June 2022

Abstract

Introduction: Congenital syphilis (CS) is preventable through timely antenatal care (ANC), syphilis screening and treatment among pregnant women. Robust CS surveillance can identify gaps in this prevention cascade. We reviewed CS cases reported to the South African notifiable medical conditions surveillance system (NMCSS) from January 2020 to June 2022. Methods: CS cases are reported using a case notification form (CNF) containing limited infant demographic and clinical characteristics. During January 2020-June 2022, healthcare workers supplemented CNFs with a case investigation form (CIF) containing maternal and infant testing and treatment information. We describe CS cases with/without a matching CIF and gaps in the CS prevention cascade among those with clinical information. Findings: During January 2020-June 2022, 938 CS cases were reported to the NMCSS with a median age of 1 day (interquartile range: 0-5). Nine percent were diagnosed based on clinical signs and symptoms only. During January 2020-June 2022, 667 CIFs were reported with 51% (343) successfully matched to a CNF. Only 57% of mothers of infants with a matching CIF had an ANC booking visit (entry into ANC). Overall, 87% of mothers were tested for syphilis increasing to 98% among mothers with an ANC booking visit. Median time between first syphilis test and delivery was 16 days overall increasing to 82 days among mothers with an ANC booking visit. Discussion: Only 37% of CS cases had accompanying clinical information to support evaluation of the prevention cascade. Mothers with an ANC booking visit had increased syphilis screening and time before delivery to allow for adequate treatment.