Comparisons of Serologic Responses of Early Syphilis to Treatment with a Single-Dose Benzathine Penicillin G Between HIV-Positive and HIV-Negative Patients

Higher Serologic Responses of Early Syphilis to Single-dose Benzathine Penicillin G Plus Doxycycline Versus Single-dose Benzathine Penicillin G Alone Among People With HIV

BACKGROUND

Single-dose benzathine penicillin G (BPG) is the preferred therapy for early syphilis, but poorer serologic responses have been observed among people with human immunodeficiency virus (PWH). No enhanced regimen has previously been shown to improve serologic outcomes of early syphilis.

METHODS

We conducted a retrospective study to compare the treatment responses to single-dose BPG combined with 7-day doxycycline versus BPG alone in PWH who presented with early syphilis. Rapid plasma reagin (RPR) titers were determined every 3-6 months for all included PWH. Serologic response was defined as at least a 4-fold decline in RPR titers at month 12.

RESULTS

During January 2018 to March 2022, 223 PWH with 307 episodes of early syphilis received single-dose BPG plus doxycycline and 347 PWH with 391 episodes received BPG alone. The median age was 36 years and baseline CD4 count was 600 cells/mm3. In the intention-to-treat with last-observation-carried-forward analysis, PWH receiving BPG plus doxycycline had a significantly higher serologic response rate at 12 months of treatment than those receiving BPG alone (79.5% vs 70.3%, respectively; P = .006). The factors associated with 12-month serologic response were RPR titer (per 1-log2 increase, adjusted odds ratio [AOR], 1.25; 95% confidence interval [CI], 1.15-1.35) and receipt of BPG plus doxycycline (AOR, 1.71; 95% CI, 1.20-2.46). In the subgroup analyses, BPG plus doxycycline was consistently associated with a better serologic response than BPG alone at month 12.

CONCLUSIONS

Among PWH with early syphilis, single-dose BPG plus doxycycline achieved higher serologic responses than BPG alone during a 12-month follow-up period.

Prevalence and Treatment Outcomes of Syphilis among People with Human Immunodeficiency Virus (HIV) Engaging in High-Risk Sexual Behavior: Real World Data from Northern Greece, 2019-2022

In this study, we aimed to assess the prevalence of syphilis among people with human immunodeficiency virus (HIV; PWH) engaging in high-risk sexual behavior, determine the stage of syphilis, and evaluate treatment efficacy. A retrospective single-center cohort study was conducted at the AHEPA University General Hospital of Thessaloniki, focusing on PWH at high risk for sexually transmitted infections (STIs) attending outpatient care from January 2019 to December 2022. Sociodemographic and clinical data were collected, incident syphilis rates were identified, associations with HIV-related characteristics were explored, and the treatment response was assessed. Among 991 participants, 94 PWH were diagnosed with syphilis, representing 9.4% of the cohort. Incident syphilis cases experienced a decrease in the early COVID-19 era compared to 2019, followed by a gradual increase leading up to 2022. The majority of syphilis cases were asymptomatic latent syphilis (71.1%). Men who have sex with men (MSM) and younger individuals exhibited higher rates of co-infection during the study period. No significant association was found between incident syphilis and HIV-related factors. Most syphilis cases (86%) were treated with benzathine penicillin G (BPG). Treatment with BPG and doxycycline showed an increased success rate (96.7% vs. 92.9%), with no statistically significant difference observed between them (p = 0.438). This study highlights the alarming incidence of syphilis among PWH engaging in high-risk sexual behavior, particularly among younger MSM. BPG remains effective, and alternative regimens like doxycycline show promise, especially in settings with penicillin shortages or patient allergies.

Syphilis for dermatologists: Current concepts

Dermatologists are familiar with the classic aspects of syphilis. Our objective in this update is to display novel features of sexually acquired syphilis, its pathophysiology, natural history, atypical clinical variants, skin of color, clinical pearls, and prospects. Textbook knowledge, congenital syphilis, epidemiology, and historical data are excluded.

Persistently Elevated Risk of Syphilis Among Human Immunodeficiency Virus-Positive Men Receiving Care in a Status-Neutral Setting: A Retrospective Analysis

BACKGROUND

Over the past decade, the incidence of primary and secondary syphilis has increased dramatically in the United States and Western Europe. Men living with human immunodeficiency virus (HIV) and those at risk of HIV infection experience disproportionately high rates of early syphilis (ES). We compared the odds of ES among HIV-positive and HIV-negative men participating in a status-neutral comprehensive HIV prevention and treatment program (CHP).

METHODS

We conducted a retrospective analysis of men aged 18 to 65 years with ≥ 1 CHP visit and ≥2 rapid plasma reagin (RPR) tests performed between January 1, 2018, and December 31, 2021. Early syphilis was defined as newly reactive RPR with a minimum titer of ≥1:4 or a ≥ 4-fold increase in the RPR titer. Multiple logistic regression analyses were performed to determine predictors of ES.

RESULTS

A total of 2490 men met the inclusion criteria, of whom 1426 (57.3%) were HIV-positive and 1064 (42.7%) were HIV-negative. Of the 393 men with ES, 284 (72.3%) were HIV-positive and 109 (27.7%) were HIV-negative. Human immunodeficiency virus-positive men had higher adjusted odds of ES (adjusted odds ratio, 2.86; 95% confidence interval, 2.45-3.27) than HIV-negative men did. Chlamydia or gonorrhea infection did not differ according to HIV status (adjusted odds ratio, 0.93; 95% confidence interval, 0.82-1.04).

CONCLUSIONS

In our status-neutral care setting, HIV-positive status was associated with significantly higher odds of ES, but not chlamydia or gonorrhea. Our findings emphasize the vulnerability of HIV-positive men to syphilis in an era of effective HIV biomedical prevention.

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

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.

A 2021 Update on Syphilis: Taking Stock from Pathogenesis to Vaccines

In 2021 the scientific community's efforts have been focused on solving the back-breaking challenge of the COVID-19 pandemic, but sexually transmitted infections (STI) are still one of the most common global health problems. Syphilis is a systemic disease caused by the spirochaete Treponema pallidum (TP) and is one of the oldest known diseases. Its incidence has increased in the last few years and syphilis still remains a contemporary plague that continues to afflict millions of people worldwide. Despite research improvements, syphilis pathogenesis is not completely clear; clinical presentation is very heterogeneous and the diagnosis can sometimes be difficult. Furthermore, few therapeutic options are available, and a vaccine has not been found yet. In this review, we describe the most recent evidence concerning the clinical manifestation, diagnosis, treatment and vaccine prospectives for this disease.