EPIDEMIOLOGY OF SYPHILIS IN BRAZIL: A STATISTICAL ANALYSIS

Abstract

Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum, which can lead to serious complications if not properly treated. Transmission occurs primarily through unprotected sexual contact and vertically, from the pregnant individual to the fetus, resulting in congenital syphilis. In Brazil, the incidence of acquired syphilis has risen exponentially, with detection rates increasing from 59.4 cases per 100,000 inhabitants in 2012 to 99.2 cases per 100,000 inhabitants in 2022, especially among young people aged 15 to 39 years. Socioeconomic factors and inequalities in access to healthcare directly influence the spread of the disease, particularly affecting vulnerable populations such as LGBT+ individuals, sex workers, and incarcerated people. The epidemiological analysis of syphilis cases in Brazil in 2024 revealed a total of 30,465 notifications between January and July, with São Paulo accounting for the majority of cases (22.68%) and Amapá presenting the lowest incidence. The disease predominantly affects men (62.15%), is more common among individuals of mixed race ("parda") (43.17%), and among those with incomplete secondary or higher education. Most diagnoses were confirmed through laboratory tests (64.4%), but 31.02% of notifications did not specify the diagnostic criteria, highlighting failures in case reporting. The cure rate was 41.01%, varying across states, with Acre reaching a high of 95.73%. Mortality remained low (0.04%), though it varied among states, with Mato Grosso do Sul showing the highest proportional lethality (0.30%). The study emphasizes that states relying on laboratory testing demonstrate greater diagnostic accuracy, whereas those dependent on clinical-epidemiological criteria face challenges in proper reporting and patient follow-up. Furthermore, regional disparities and limited access to healthcare services hinder disease control. Awareness campaigns—especially targeted at vulnerable populations—and expanded access to laboratory diagnosis are essential to reducing the spread of syphilis.