The Rise of Syphilis Infections and Reinfections over a Decade (2009–2019) in the Bolognese Area: A Retrospective Analysis

Syphilis has resurged globally, especially in urban areas of developed countries. This study analyses syphilis cases over a decade at an STD centre in Bologna, Italy, examining new diagnoses, reinfections, and impacts on high-risk subgroups, compared with national and European data. Data from 2009-2019 were retrospectively reviewed, including primary, secondary, early latent, late latent, and indeterminate syphilis cases, as per WHO guidelines. Cases of tertiary syphilis and serological-only diagnoses were excluded. Statistical analysis was conducted using IBM SPSS Statistics 26 with logistic regression and chi-square tests. A total of 1086 syphilis cases were identified, rising from 43 cases in 2009 to 157 in 2019-a 265% increase over the decade. In 2019, reinfections accounted for 23.7% of cases, primarily among men who have sex with men (MSM, 82.1%), with an HIV co-infection rate of 37.6%. The most affected age group was over 45 years. Bologna's syphilis rates consistently exceeded European averages, with a higher median age, indicating unique transmission patterns and public health challenges. The high reinfection rate among MSM and older individuals emphasises the need for targeted public health initiatives. The sharp rise in cases highlights potential influences such as Bologna's population dynamics and the increased use of Pre-Exposure Prophylaxis (PrEP). Focused public health efforts, particularly on high-risk groups, are critical to address this challenge effectively.