Prevalence of Syphilis in Vulnerable Populations in a Metropolis in the Brazilian Amazon

Syphilis ranks 4th among the most alarming curable sexually transmitted infections (STIs) in the world. Despite being preventable and curable, according to the most recent World Health Organization (WHO) report, syphilis cases among adults aged 15 to 49 years increased 30% between 2020 and 2022. The scenario of STI incidence is strongly influenced by the characteristics and particularities of populations, with vulnerable populations being the most impacted due to greater exposure to multiple risk factors. To describe the prevalence of syphilis cases associated with socioeconomic characteristics of the population of the city of Belém. This is an observational, descriptive and cross-sectional study with a quantitative approach conducted in the city of Belém. Data were obtained through interviews using a structured questionnaire, in individuals invited to voluntarily participate in the study, followed by signing of the Informed Consent Form (TCLE). Subsequently, a venous blood sample was collected in a tube containing EDTA anticoagulant to perform a rapid test for T. pallidum. Eligible participants were residents of Belém, aged 18 to 30 years, belonging to key populations of socioeconomic vulnerability and LGBTQIAPN+. Individuals unable to provide information consciously and independently and those without fixed residence in the municipality were excluded. Fisher's Exact test was performed, assuming a significance value of < 0.0005 in RStudio. This study was approved by the Research Ethics Committee (7.084.723). Among the 66 individuals included in the study, the majority declared themselves heterosexual (52%), brown (48%), single (93%), with complete high school education (93%), unemployed (75%), with income between 1 and 2 minimum wages (53%) and age at first sexual intercourse between 15 and 18 years (52%). Despite the preconditions of vulnerability and high potential risk of infection, all participants in the study tested negative for syphilis. The negative results for syphilis among the studied sample are encouraging, considering the concerning global scenario of this infection. They indicate that individuals recognize the risks associated with syphilis and are practicing safer sexual behaviors, suggesting that variables such as schooling may have a protective effect against this infection.