A Call for International Collaboration to Improve Definitions for the Surveillance of Congenital Syphilis

To the Editors: In 2022, the World Health Organization estimated 700,000 annual cases of congenital syphilis (CS), including 390,000 adverse birth outcomes.1 The burden of disease in the African region was 5 times higher than the next most prevalent region, the Americas.2 The European region alone met the Elimination of Mother to Child Transmission of syphilis target of <50/100,000 live births, threatening the proposed attainment of this goal by 2030.2 After an earlier launch at the World Society of Paediatric Infectious Diseases conference in Durban in 2023, the Prevent Syphilis network and Penta ID network convened a collaborative session at the 43rd European Society for Paediatric ID congress in Bucharest on May 28, 2025. The session was attended by over 180 delegates. The aim of the session was to review the current status of global CS surveillance and discuss potential strategies to improve accuracy. Research data from Malawi, Brazil and Greece were presented alongside surveillance data from the United Kingdom and the European Centre for Disease Prevention and Control. Several themes were identified. First, while antenatal Treponemal rapid point-of-care tests have improved access to treatment, burden of disease estimates based on this strategy may be inflated. In a Malawian cohort, the surveillance definition estimate was double the true cases of CS diagnosed by the reference standard.3,4 Conversely, institutional data from Brazil and Greece indicated that surveillance definitions based on microbiological confirmation in those countries underestimated the burden of disease. Finally, inadequate surveillance of stillborn infants born to syphilis seropositive birthing parents is an issue worldwide. Several priority areas for future research and evaluation were identified. First, there is a need to understand the geographic variability in current surveillance strategies and better quantify the epidemiology of CS through prospective cohorts. Second, there is a need to quantify the potential over- or under-estimation of CS incidence based on the various testing strategies in place globally so that they may be refined. Third, the use of novel diagnostics (near-patient molecular diagnostics, IgM and non-Treponemal rapid point of care tests), either alone or within clinical prediction models, may provide a feasible approach to improving clinical care and surveillance and should be evaluated further. Collaboration between researchers, industry, funders and policy makers facilitated by networks such as Prevent syphilis and Penta can inform these efforts and increase their impact.