Epidemiological and clinical aspects of syphilis incidence in the Russian Federation and the Republic of Tajikistan: comparative analysis

The paper discusses the epidemiological and clinical aspects of syphilis in the Russian Federation and the Republic of Tajikistan, as well as the main key trends and challenges associated with this infection. In 2021 and 2022, after a long period of decline, there was a significant rise in the incidence of syphilis in Russia, with a 69.7 % increase compared to 2020. Increased incidence in 2021–2022 was largely due to the increased incidence among foreign citizens: 2,801 in 2020, 7,710 in 2021, and 12,748 in 2022. In 2023, 10,160 cases of syphilis were detected among foreign citizens in Russia, of which 1,875 (18.5%) were from Tajikistan, whereas only 368 cases were reported in Tajikistan. In Russia, the proportion of advanced and unspecified syphilis increased from 2015 to 2023 due to increased incidence among foreign citizens. Since 2019, advanced forms of syphilis that were previously undetected have also been reported in the Republic of Tajikistan. The effective work of dermatovenereological services in the Russian Federation and the Republic of Tajikistan has contributed to a significant decrease in the incidence of syphilis among children and adolescents. In Russia, the incidence rate among children aged 0 to 14 decreased from 228 cases in 2015 to 34 in 2023, and among adolescents aged 15 to 17, it decreased from 391 to 159 cases. No syphilis cases in these age groups have not been reported in Tajikistan. The number of cases of congenital syphilis in Russia decreased from 63 to 12, while in Tajikistan this value varied from 0 to 5 cases. The article highlights the differences in the algorithms for diagnosing syphilis in specific target populations and in advanced forms of the disease, which can lead to undiagnosed cases of the disease.