Congenital syphilis prevention cascade in Brazil, 2015–2023: a national analysis of regional and sociodemographic inequalities

Congenital syphilis (CS) remains a major public health challenge despite the availability of effective diagnostic and treatment strategies. In Brazil, increasing rates of gestational and CS suggest persistent gaps in prevention. We evaluated the CS prevention cascade in Brazil and examined individual and contextual factors associated with cascade completion. We conducted a nationwide observational study using publicly available data from the Brazilian Information System on Live Births and the Notifiable Diseases Information System from 2015 to 2023. The prevention cascade included live births, antenatal care utilization, gestational syphilis diagnosis, treatment adequacy, partner treatment, and congenital syphilis outcomes. Descriptive analyses estimated cascade indicators and temporal trends. Multivariable logistic regression models evaluated factors associated with timely diagnosis, compatible treatment regimen, potentially correct treatment, and partner treatment among notified gestational syphilis cases. Between 2015 and 2023, Brazil registered 25,099,825 live births, 558,951 gestational syphilis cases, and 221,120 congenital syphilis cases. Antenatal care coverage was high, with 98.2% of women attending at least one visit and 71.6% attending seven or more visits. However, substantial losses occurred throughout the prevention cascade. Among women with gestational syphilis, 69.2% were diagnosed during the first or second trimester, 64.6% received a treatment regimen compatible with the reported clinical stage, 48.6% met criteria for potentially correct treatment, and 46.4% reported partner treatment. Gestational syphilis rates increased from 10.7 to 34.4 cases per 1,000 live births, while congenital syphilis rates increased from 6.6 to 10.0 per 1,000 live births. Lower adjusted odds ratios of cascade completion were consistently associated with “ Pardo ” (Mixed-race) and Indigenous race/color, residence outside the Southeast region, lower educational attainment, and lower municipal social progress. Marked regional inequalities persisted across all cascade stages, particularly in the North and Northeast regions. Despite nearly universal antenatal coverage, major opportunities for CS prevention in Brazil are lost after women enter care, particularly during treatment and partner management. Persistent social, educational, and territorial inequalities affect all stages of the prevention cascade. Improving antenatal care quality, strengthening partner management, and addressing social determinants are essential to accelerate congenital syphilis elimination in Brazil and other settings with persistent vertical transmission.