PREVALENCE OF SYPHILIS AND ASSOCIATED FACTORS IN NEW HCV INFECTIONS IN A SPECIALIZED CENTER

Hepatitis C (HCV) is one of the main causes of liver disease worldwide. Efforts toward micro-elimination of the disease among key populations such as people living with HIV/AIDS (PVHA), people who inject drugs (PWID), men who have sex with men (MSM) and people deprived of liberty are essential to control this disease. Some ulcerative sexually transmitted infections (STIs), such as syphilis, are associated with a higher risk of HCV infection. However, there are no comprehensive national data on syphilis in new HCV cases. We evaluated the prevalence of syphilis and associated factors in new HCV cases in a specialized center for STI care. Retrospective observational study analyzing demographic and clinical-epidemiological information from medical records of individuals with HCV seen at a reference center for STI/PVHA care. New HCV cases were defined as those diagnosed with HCV infection between January 2015 and December 2024. Syphilis diagnoses made in the 12 months prior to or at the time of HCV diagnosis were considered. Proportions of clinical variables between groups with and without syphilis were compared using Fisher's exact test (two-tailed p < 0.05). We identified 58 cases of acute HCV, all included in the analysis. Among them, 27 (47.8%) had a diagnosis of some STI in the 12 months prior to or at HCV diagnosis. Syphilis was diagnosed in 24 cases (43.1%). Among these, all were male, 23 (95.8%) were PVHA, 23 (95.8%) MSM, 1 PrEP user (4.1%), 17 (70.8%) reported multiple sexual partners in the last year and 8 (33.3%) reported prior use of recreational drugs. In the group without syphilis (34 cases), 29 (85.2%) were male, 19 (55.8%) PVHA, 19 (55.8%) MSM, 6 (17.6%) PrEP users, 15 (44.1%) reported multiple sexual partners in the last year and 11 (32.5%) used recreational drugs. There was a significant association between male sex or PVHA status and syphilis diagnosis (p = 0.0008 for both). There was no association with history of PrEP use, multiple sexual partnerships or recreational drug use. We found a high prevalence of syphilis among new HCV cases and a significant association with PVHA and male sex. Specific interventions regarding HCV testing during serological follow-up of individuals diagnosed with syphilis should be considered.