Epidemiology of syphilis at the national level in Kazakhstan, 2022–2025

Abstract Background Syphilis, caused by Treponema pallidum , remains a major sexually transmitted infection and a public-health concern because of sustained incidence, the risk of severe complications, and vertical transmission. For Kazakhstan and Central Asia, few recent studies have described national syphilis surveillance data in a way that links temporal trends to regional variation and to maternal and congenital indicators. This study describes the registered crude incidence of syphilis in Kazakhstan for 2022–2025 and its regional, maternal, congenital, clinical, and demographic distribution. Methods We conducted a retrospective, nationwide, descriptive ecological surveillance study of official national statistical collections issued by the Ministry of Health of the Republic of Kazakhstan. Registered crude national incidence was assessed for 2022–2025. Because the 2022 administrative reform created Abai, Ulytau, and Zhetysu regions and altered the boundaries of their parent regions, directly comparable regional analyses used all 20 administrative units for 2023–2025. Analyses included descriptive statistics, the Friedman test for repeated measures, descriptive 2025 regional-to-national incidence rate ratios (IRRs), and change in regional incidence between 2023 and 2025. Maternal, congenital, clinical-form, age, and sex indicators were summarised descriptively from annual administrative Form 12-STI aggregates; maternal and congenital indicators were additionally expressed per 100,000 live births. Results Registered crude national syphilis incidence declined from 10.5 per 100,000 population (2,055 cases) in 2022 to 8.2 per 100,000 (1,678 cases) in 2025, an overall reduction of 21.9%. Annual reductions were 12.4% in 2023, 7.6% in 2024, and 3.5% in 2025. Regional incidence remained heterogeneous in 2025 (2.7–17.7 per 100,000), but the Friedman test did not detect evidence of an overall difference in regional incidence across 2023–2025 (chi-square = 1.85, p = 0.397). In 2025, descriptive IRRs ranged from 2.16 in Karaganda to 0.33 in Kyzylorda. From 2023 to 2025, the largest reported increase was in East Kazakhstan (+ 113.5%) and the largest decrease in Kyzylorda (-79.4%). Reported syphilis cases among pregnant women decreased by 39.8%, and congenital syphilis cases decreased by 72.7% from the 2023 peak. Expressed per 100,000 live births, the congenital syphilis case rate fell from 2.84 in 2023 to 0.90 in 2025. Conclusions The registered crude incidence of syphilis declined during 2022–2025, but substantial regional heterogeneity and persistent congenital cases remained. Because the outcome is registered surveillance incidence, the decline may partly reflect testing and reporting practices rather than transmission alone. The findings support geographically targeted surveillance and prevention, together with continued strengthening of antenatal screening.