Syphilis Infections, Reinfections and Serological Response in a Large Italian Sexually Transmitted Disease Centre: A Monocentric Retrospective Study

Abstract

Background: Syphilis infection does not confer definitive and protective immunity against reinfection, and crucial aspects of repeated episodes of syphilis are far from being understood, especially among people living with HIV (PLWH). Methods: In order to explore the burden of syphilis in a large cohort of HIV-negative patients and PLWH, this retrospective study describes the demographics, clinical presentation and treatment outcome of patients with syphilis treated at our clinic from 2013 to 2021. Results: Within the study period, 1859 syphilis episodes (827, 44.5% first infections and 1032, 55.5% reinfections) were recorded. A total of 663 patients, of whom 347 (52%) had PLWH, were considered. Syphilis was mostly diagnosed in males (77%) and European (79%) patients. More than half of syphilis episodes were recorded during the late latent stage (64%) or during follow-up/screening visits for other diseases, while symptomatic stages led to a diagnosis in almost half of HIV-negative patients (p < 0.001). PLWH with syphilis infection were predominantly homo/bisexual (p < 0.001). A significantly higher rate of syphilis reinfection was observed in PLWH, who also demonstrated a higher range of subsequent episodes. The serofast state was found to be similar at the 6- and 12-month follow-up visits. The multivariate analysis carried out in the HIV-positive group showed that an RPR titre >1:16 was an independent predictor for serological non-response. Conclusions: Syphilis reinfections are predominantly diagnosed in HIV-positive MSM. The high rate of asymptomatic presentation among PLWH supports the role of periodical syphilis screening. In PLWH, the only baseline factor associated with an increased risk of non-response was an RPR titre >1:16, while assessment at 12 months after treatment increased the possibility of detecting a serological response, indicating that PLWH have a slower serological response to treatment.

The Arg753Gln Polymorphisms in Toll-like Receptor 2 in a Syphilis-Infected and Control Population in The Netherlands: Can Differences in the Number of Self-Reported Sexual Contacts Indicate Protection against Syphilis?

“…However, it is unknown whether and to what extent this could contribute to the differences observed between this study and the Grillová et al [18] syphilis TLR2 polymorphism study. HIV positivity could affect participants' distribution in the control group or case group, as HIV coinfection can cause serofast or non-responding serology [30]. Despite that, a low prevalence of HIV positivity and no discrimination between active and past infection in participants limit the effect of HIV coinfection in our study.…”

HIV Infection Modifies the Role of Prior Treponema pallidum Infection in the Clinical Presentation of Early Syphilis Among Adult Patients From Sexually Transmitted Infection Clinics in Peru

“…[1][2][3] Because previous infection does not prevent future episodes, 4 reinfection is not only possible but also frequent among high-risk populations. 5,6 It have been well documented in rabbit models that previous infections confer partial immunity for future exposure, expressed as less symptomatic infection or no infection after repeated T. pallidum inoculation. 7 Some studies in humans have reported that in repeat T. pallidum infections, the clinical presentation may be less symptomatic 8,9 or more frequently asymptomatic, 10,11 but others have found no differences in the clinical presentation of syphilis in repeat infections.…”

“…Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum , which remains a worldwide public health problem 1–3 . Because previous infection does not prevent future episodes, 4 reinfection is not only possible but also frequent among high-risk populations 5,6 …”

Evaluation of Automated Processing of Electronically Reported Serological Tests for Syphilis Using Current and Historical Syphilis Results Compared With Traditional Reactor Grid Processing in Florida

“…Syphilis is a sexually transmitted infection, caused by the bacterial spirochete Treponema pallidum, although syphilis is curable with antibiotic treatment reinfections are possible. 3,4 Consistent with other spirochetes, direct detection of T. pallidum using available laboratory testing is challenging. Currently, case definitions for syphilis and other notifiable spirochetes use a combination of indirect detection methods to assess clinical and surveillance significance.…”

“…Syphilis is a sexually transmitted infection, caused by the bacterial spirochete Treponema pallidum , although syphilis is curable with antibiotic treatment reinfections are possible 3,4 . Consistent with other spirochetes, direct detection of T. pallidum using available laboratory testing is challenging.…”