Global, regional, and national burden of syphilis in children under 5 years from 1990 to 2021

Mother-to-child transmission of syphilis has raised much concern for the dramatically increasing incidence in recent years. This study aims to assess the global, regional, and national disease burden of syphilis in children under 5 years from 1990 to 2021. Data were extracted from the 2021 Global Burden of Disease study. Temporal trends were evaluated using the average annual percentage change. Segmented regression was applied to estimate breakpoints and the corresponding slopes. Spearman correlation analysis was performed to analyze the correlation of disease burden and SDI. Slope index of inequality and concentration index were calculated, and ARIMA model was performed. In 2021, an estimated 384,121 (95% UI: 314,943 to 460,835) new cases were reported among syphilis under 5 years, with an age-standardized incidence rate of 58.36 (95% UI: 47.85 to 70.02) per 100,000 population. Reported death cases were 72,148 (95% UI: 27,130 to 144,529) with an ASR of 10.96 (95% UI: 4.12 to 21.96). A sharp increase in both incidence and prevalence has been observed since 2016, with APCs as high as 7.06% and 8.11%. The mortality and DALY rates have increased from 2019 with an APC of 7.92%. The neonatal period contributed to 97.7% deaths and DALYs. The disease burden is inversely associated with overall socioeconomic development, with disparities persisting between higher- and lower-resource regions and countries. These data suggest a global re-emergence of syphilis in children under 5 years and highlight the priority for enhancing prenatal screening and interventions, providing timely and adequate maternal treatment, and preventing neonatal mortality. IMPORTANCE: Mother-to-child transmission of syphilis has raised much concern for the dramatically increasing incidence and societal well-being in recent years. We depict the global, regional, and national temporal trend of syphilis in children under 5 years from 1990 to 2021, and our study has demonstrated a sharp upward trend in disease burden in recent years. The neonatal death contributed to 97.7% deaths and DALYs in syphilis among children under 5 years, indicating that premature mortality was the overwhelming driver of DALYs. The disease burden is inversely associated with overall socioeconomic development, with disparities persisting between higher- and lower-resource regions and countries. By understanding the trends and patterns, policymakers and healthcare providers can develop targeted and evidence-based strategies to reduce the mother-to-child transmission and overall burden of syphilis in children under 5 years.