Risk factors associated with prevalent and incident syphilis among an HIV-infected cohort in Northeast China

High rates of Treponema pallidum, Neisseria gonorrhoeae, Chlamydia trachomatis, or Trichomonas vaginalis co-infection in people with HIV: a systematic review and meta-analysis

PURPOSE

People living with HIV (PWH) experience a disproportionate burden of sexually transmitted infections (STIs), leading to more severe health outcomes and increasing the risk of HIV transmission. The presence of untreated STIs can accelerate HIV disease progression, while HIV infection can complicate STI diagnosis and treatment. Despite this interconnectedness, comprehensive data on the global prevalence of specific STIs among PWH remain limited. This systematic review aims to synthesize existing data to provide a more accurate picture of the prevalence of co-infection with Treponema pallidum, Neisseria gonorrhoeae, Chlamydia trachomatis or Trichomonas vaginalis in PWH, while also identifying critical knowledge gaps and informing future research priorities.

METHODS

We searched databases for eligible studies reporting the prevalence of Treponema pallidum, Neisseria gonorrhoeae, Chlamydia trachomatis, or Trichomonas vaginalis among PWH, published from January 1, 2000, to February 1, 2023. From 22,290 identified articles, 127 independent studies meeting the inclusion criteria were included in this meta-analysis.

RESULTS

The overall global co-infection prevalence of Treponema pallidum, Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis in PWH, was 4.8% (95%CI: 4.7-5.0%), 0.8% (95%CI: 0.6-0.9%), 2.5% (95%CI: 2.2-2.7%), and 3.0% (95%CI: 2.7-3.3%), respectively. The global prevalence of these four STIs in PWH is high, especially in Africa and Southeast Asia and in MSM and TGW populations. Based on the subgroup analyses, we further found that there was a high prevalence of Treponema pallidum and Chlamydia trachomatis in Southeast Asia and a high infection of Trichomonas vaginalis in the whole of Africa. Treponema pallidum infection was more common in males than females, and Chlamydia trachomatis and Trichomonas vaginalis infections were more common in females than males. Besides, high infection rates of Treponema pallidum, Neisseria gonorrhoeae, and Chlamydia trachomatis were detected in men who have sex with men (MSM) + transgender women (TGW), while high infection rates of Trichomonas vaginalis were found in sex workers and pregnant women.

CONCLUSION

The study confirmed high prevalence of four sexually transmitted pathogens in PWH, noting regional, gender, and subpopulation-specific differences. It offered insights for targeted interventions and healthcare strategies. The research underscored the necessity for enhanced data collection and expanded screening/treatment for vulnerable populations and regions.

The impact of the National Syphilis Prevention Program on the prevalence of syphilis among people living with HIV in China: a systematic review and meta-analysis

INTRODUCTION

In 2010, China launched the 10-year National Syphilis Prevention and Control Program to curb the spread of syphilis by integrating syphilis screening and treatment with HIV services. Herein, we aimed to evaluate changes in the prevalence of syphilis among people living with HIV (PLHIV) in China.

METHODS

We conducted this systematic review and meta-analysis by searching the PubMed, Embase, Web of Science, China Biomedical Literature, China National Knowledge Infrastructure, Wanfang and CQVIP databases from inception to 1 June 2024 to obtain relevant articles. A total of 75 studies were ultimately included. We used a DerSimonian‒Laird random effects model to estimate the prevalence and 95% confidence interval of syphilis among PLHIV.

RESULTS

The overall prevalence of syphilis among PLHIV in China was 18.6% (95% CI 16.5-21.0). Regional differences (R2 = 15.29%) were observed in the prevalence rates: 22.2% (18.9-25.8) in the eastern region, 19.0% (15.1-23.8) in the central region and 14.0% (11.1-17.5) in the western region. The prevalence decreased from 22.8% (18.4-27.9) before 2010 to 17.0% (14.6-19.6) in 2010 and thereafter (R2 = 5.82%). Among PLHIV via homosexual transmission, the prevalence of syphilis was 24.9% (21.3-28.9), which significantly declined from 33.8% (27.5-40.8) to 21.4% (18.3-24.9) in 2010 and thereafter (R2 = 22.35%). The prevalence of syphilis was significantly higher in men living with HIV than in women living with HIV (pooled odds ratio 1.67, 95% CI 1.29-2.15), with the highest prevalence in the eastern region (2.55, 95% CI 1.80-3.59).

DISCUSSION

The prevalence of syphilis among PLHIV, particularly in cases of homosexual transmission, has declined. There was a correlation between the prevalence of syphilis and regional economic conditions, with a greater burden in developed eastern coastal areas. Additionally, the risk of syphilis differed across sexes, with men living with HIV having a higher risk.

CONCLUSIONS

There has been preliminary success in the control of syphilis among PLHIV, but there is still a long way to go to meet the WHO's 2030 syphilis prevention and control goal. Syphilis prevention measures should be integrated into broader health policies and development plans, particularly in high-burden regions and populations.

Sero-prevalence of syphilis infection among people living with HIV in Sierra Leone: a cross-sectional nationwide hospital-based study

BACKGROUND

Globally, there were an estimated 7.1 million new syphilis infections in 2020, with more than 30% of these new infections reported in African countries such as Sierra Leone. Despite this, there is no HIV-specific syphilis screening program in Sierra Leone. Thus, data are needed to inform public health practice. In this study, we aimed to determine the prevalence of syphilis seropositivity and factors associated with syphilis seropositivity among people living with HIV (PLHIV).

METHODS

A cross-sectional study was conducted at 10 health facilities in Sierra Leone, among adults with HIV, aged 18 years or older, from September 2022 to January 2023. Parameters of interest were collected including age, sex, marriage, antiretroviral therapy (ART) regimen, HIV viral load, duration of ART treatment, and hospital level of care. The syphilis antibody was detected by a rapid test based on immunochromatography assay. Data were analyzed using R-software version 4.2.3 (R Core Team, Vienna, Austria). Pearson's χ2 test, Fisher's exact test and Kruskal-Wallis H test were applied to assess the differences in syphilis seropositivity between groups as appropriate. Univariate logistic regression and multivariate logistic regression analysis was used to assess factors associated with syphilis seropositivity. The level of statistical significance was set at P < 0.05.

RESULTS

Of the 3082 PLHIV individuals in our study, 2294 (74.4%) were female and 2867 (93.0%) were receiving ART. With a median age of 36 years, 211 (6.8%, 95% CI 6.0-7.7) were positive for syphilis. The prevalence of syphilis was highest in people aged 60 years and over (21.1%, 95%CI 14.7-29.2), followed by people aged 50-60 years (15.5%, 95%CI 11.9-19.9) and in the widowed population (11.9%, 95%CI 8.9-15.8). There were no differences in syphilis seropositivity between gender, ART status, ART regimen, duration of ART, HIV viral load and hospital level of care. Older age (50-60 years: adjusted OR 3.49, 95%CI 2.09-5.85 P < 0.001; 60-100 years: adjusted OR 4.28, 95%CI 2.21-8.17, P < 0.001) was an independent predictor of seropositive syphilis.

CONCLUSIONS

We observed a high prevalence of syphilis among PLHIV. Older people and widowed population have higher syphilis seropositivity. Older age was an independent predictor of syphilis positivity. Therefore, we call for the integration of syphilis screening, treatment and prevention in HIV services.

Prevalence of syphilis among people living with HIV and its implication for enhanced coinfection monitoring and management in China: A meta-analysis

Background

People living with HIV (PLWH) are at an increased risk of syphilis infection. The objectives of this study were to assess the overall prevalence of syphilis among PLWH in China and identify factors associated with syphilis infection among PLWH.

Methods

We searched Medline, Embase, China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals Database (VIP), Wan-fang Data, and Chinese Biomedical Literature Database (CBM) to identify studies that reported the prevalence of syphilis among PLWH in China and were published in English or Chinese from January 1, 1990, to May 31, 2022. The reference lists of retrieved articles and relevant reviews were also checked to identify additional studies. A random-effect model was fitted to calculate the pooled syphilis prevalence among PLWH. Subgroup analyses, meta-regression analyses and sensitivity analyses were conducted to determine the potential source of heterogeneity.

Results

Of the 1,599 articles screened, 29 studies involving 34,740 participants were eligible for inclusion in this meta-analysis. The overall prevalence of syphilis among PLWH in China was 19.9% [95% confidence interval (CI): 15.4-24.8%, I 2 = 98.9%]. Subgroup analysis showed that the pooled prevalence of syphilis among men who have sex with men (MSM) with HIV (21.9%, 95% CI: 17.2-26.9%) was much higher than that among heterosexuals (10.3%, 95% CI: 5.2-16.8%); there was regional diversity in the prevalence of syphilis, the highest in northern China (31.7%, 95% CI: 17.9-47.4%), followed by central-southern China (26.7%, 95% CI: 11.4-45.7%), and the lowest in northwestern China (15.0%, 95% CI: 6.9-25.4%); the syphilis prevalence among PLWH decreased as CD4 + T cell count increased (19.6% in CD4 + T cell < 200 vs. 8.7% in ≥ 500) and was higher among non-antiretroviral therapy (non-ART) HIV-infected patients (21.0%, 95% CI: 9.9-35.0%) than that among ART ones (16.1%, 95% CI: 3.9-34.3%).

Conclusions

Our study showed a significantly high prevalence of syphilis among PLWH in China, particularly among MSM with HIV. Developing national guidelines for the integrated screening, monitoring, and management of HIV and syphilis as well as syphilis diagnosis and treatment training programs for physicians at designated HIV treatment hospitals is urgent and crucial to combat HIV and syphilis coinfection in China.

Investigating latent syphilis in HIV treatment-experienced Ethiopians and response to therapy

Objectives

We investigated people with HIV (PWH) receiving combination antiretroviral therapy (cART) for latent syphilis infection prevalence, risk factors, treatment response, and neurosyphilis.

Methods

A prospective follow-up study was conducted on PWH and latent syphilis. The cases were randomly assigned to receive either benzathine penicillin G (BPG) or doxycycline (DOXY), and the posttreatment response was evaluated after 12 and 24 months. The traditional algorithm was used for serodiagnosis, and a semi-quantitative rapid plasma reagin (RPR) test monitored disease activity and treatment effectiveness.

Results

Of the 823 participants, 64.8% were women, and the mean age was 41.7±10 years. Thirty-one (3.8%) of the participants (22 males and nine females) had latent syphilis. The risk factors were male sex (aOR = 3.14), increasing age (aOR = 1.04 per year), and cART duration (aOR = 1.01 per month). Baseline RPR titers were: ≤1:4 in 19 (61.3%), between 1:8 and 1:32 in 10 (32.2%), and >1:32 in 2 (6.4%). None of the seven cerebrospinal fluid analyses supported a neurosyphilis diagnosis. In the 12^th month of treatment, 27 (87.1%) had adequate serological responses, three (9.7%) had serological nonresponse, and one (3.2%) had treatment failure. Syphilis treatment was repeated in the last four cases with the alternative drug. In terms of adequate serologic response, both therapies were comparable at the 12^th month, p = 0.37. All cases responded to treatment in the 24^th month.

Conclusion

In PWH receiving cART, latent syphilis occurred more in men than women, suggesting an investigation of sexual practices and the impact of antenatal syphilis screening. Syphilis disease activity reduces in the latent stage. Therefore, the routine cerebrospinal fluid analysis contributes little to the diagnosis of asymptomatic neurosyphilis and the treatment success of latent syphilis. DOXY is an alternative to BPG, and cART improves serologic response to latent syphilis treatment.

Factors associated with HIV/syphilis co-infection initiating of antiretroviral therapy

OBJECTIVE

To evaluate the prevalence and factors associated with HIV/syphilis co-infection in people initiating antiretroviral therapy in Belo Horizonte, capital of the state of Minas Gerais.

METHODS

A sectional section of a prospective cohort study was carried out with people living with HIV, treatment-naive, initiating antiretroviral therapy, older than 16 years, and in follow-up treatment at specialized HIV/Aids care services in Belo Horizonte. Sociodemographic, behavioral, clinical, laboratory and pharmacological treatment-related data were obtained through interviews, medical records, and information systems for logistical control of antiretroviral medications and laboratory tests. The dependent variable was the first episode of active syphilis, recorded by the physician in clinical records, within 12 months after beginning of the antiretroviral therapy. Factors associated with HIV/syphilis co-infection were assessed using binary multiple logistic regression.

RESULTS

Among the 459 individuals included, a prevalence of 19.5% (n = 90) of sexually transmitted infections (STI) was observed, with syphilis (n = 49) being the most frequent STI in these individuals. The prevalence of HIV/syphilis co-infection was 10.6% (n = 49), and the associated independent factors were alcohol use (OR = 2.30; 95%CI: 1.01–5.26), and having a diagnosis of other sexually transmitted infections (OR = 3.33; 95%CI: 1.24–8.95).

CONCLUSIONS

There was a high prevalence of HIV/syphilis co-infection in people living with HIV initiating antiretroviral therapy in Belo Horizonte. HIV/syphilis co-infection was associated with behavioral and clinical factors, such as alcohol use and diagnosis of other sexually transmitted infections. Prior knowledge about the factors associated with this co-infection may support the decisions of health professionals engaged in the care to people living with HIV, with regard to timely diagnosis, guidance, follow-up and adequate treatment, both for syphilis and HIV.

Simple-to-use nomogram for predicting the risk of syphilis among MSM in Guangdong Province: results from a serial cross-sectional study

Background

The purpose of this study was to develop and validate a simple-to-use nomogram for the prediction of syphilis infection among men who have sex with men (MSM) in Guangdong Province.

Methods

A serial cross-sectional data of 2184 MSM from 2017 to 2019 was used to develop and validate the nomogram risk assessment model. The eligible MSM were randomly assigned to the training and validation dataset. Factors included in the nomogram were determined by multivariate logistic regression analysis based on the training dataset. The receiver operating characteristic (ROC) curves was used to assess its predictive accuracy and discriminative ability.

Results

A total of 2184 MSM were recruited in this study. The prevalence of syphilis was 18.1% (396/2184). Multivariate logistic analysis found that age, the main venue used to find sexual partners, condom use in the past 6 months, commercial sex in the past 6 months, infection with sexually transmitted diseases (STD) in the past year were associated with syphilis infection using the training dataset. All these factors were included in the nomogram model that was well calibrated. The C-index was 0.80 (95% CI 0.76–0.84) in the training dataset, and 0.79 (95% CI 0.75–0.84) in the validation dataset.

Conclusions

A simple-to-use nomogram for predicting the risk of syphilis has been developed and validated among MSM in Guangdong Province. The proposed nomogram shows good assessment performance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06912-z.

Syphilis seroprevalence and seroconversion among people newly diagnosed with HIV during the pre-antiretroviral therapy period in rural China

Syphilis has a high incidence among people living with HIV (PLHIV), which may be attributable to their similar sexual transmission route. A retrospective cohort study was conducted during the period 2009-2015 to investigate the syphilis seroprevalence and incidence of syphilis seroconversion among newly-diagnosed PLHIV in rural Yunnan, China. Recent HIV infection among PLHIV was identified by BED capture enzyme immunoassay. PLHIV were followed until they initiated antiretroviral therapy. Syphilis serology was conducted at baseline and each follow-up over the study period. Among 2162 participants, the syphilis seroprevalence at baseline was 2.7%, 95% confidence interval (CI) (2.4-3.1). Single and divorced (versus married) (aOR = 2.9, [1.1-7.4]; 5.9, [2.4-14.7], respectively), employed in the service industry (versus unemployed) (2.8, [1.4-5.6]), being diagnosed with HIV in hospitals (versus voluntary counselling and testing) (5.1, [2.0-12.9]), recent HIV infection (17.9, [8.5-37.9]) and inconsistent condom use in the previous three months (versus consistent condom use) (6.2, [2.8-13.4]) were associated with higher risk of syphilis infection at baseline. Participants contributed 1955.4 person-years (PYs) of follow-up, with a median follow-up period of 0.9 years (IQR: 0.5-1.9) and the incidence of syphilis seroconversion was 2.2 (95% CI 1.5-2.9) per 100 PYs. The syphilis seroprevalence at baseline (aHR 3.7, [1.8-7.9]), had a HIV-negative partner at baseline (3.9, [1.5-9.8]) and inconsistent condom use in the last three months at baseline (6.0, [1.4-25.4]) were associated with higher risk of syphilis seroconversion. Our findings indicate that the public health response should be escalated to minimise the spread of syphilis co-infection among PLHIV and reducing condomless sexual behaviours after HIV diagnosis.

Prevalence and associated factors of Treponema pallidum infection in a rural area of southwestern China

Background

Epidemiological data on Treponema pallidum infection are scarce from the southwestern region of China. The purpose of this study was to determine the distribution and determinants of T. pallidum infection in the region.

Methods

A community-based cross-sectional study of 2608 participants aged ≥14 years was conducted in a rural area of southwestern China in 2014–15. A pretested questionnaire was used to collect sociodemographic characteristics and other factors associated with T. pallidum infection. The diagnoses of T. pallidum, human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) infections were determined by commercial test kits. Logistic regression analysis was used to determine the correlates for T. pallidum infection, and adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated.

Results

The prevalence of T. pallidum infection was 1.2% (95% CI 0.8 to 1.7%). Risk factors varied by gender. In the male group, T. pallidum infection was significantly associated with ever injection drug use (aOR = 9.42, 95% CI 2.47 to 35.87) and HCV infection (aOR = 13.28, 95% CI 3.20 to 51.70). In the female group, correlates for T. pallidum infection included spouse having syphilis (aOR = 126.66, 95% CI 7.58 to 2122.94), ever having blood transfusion (aOR = 10.51, 95% CI 1.58 to 41.21) and HBV infection (aOR = 4.19, 95% CI 1.35 to 10.93).

Conclusions

The prevalence of T. pallidum infection was high in the rural area of southwestern China. Correlates for T. pallidum infection varied with sex specific. Intervention should be developed for the prevention and control of T. pallidum infection.

Repeated Syphilis Episodes in HIV-Infected Men Who Have Sex With Men: A Multicenter Prospective Cohort Study on Risk Factors and the Potential Role of Syphilis Immunity

Background

Syphilis is re-emerging globally in general and HIV-infected populations, and repeated syphilis episodes may play a central role in syphilis transmission among core groups. Besides sexual behavioral factors, little is known about determinants of repeated syphilis episodes in HIV-infected individuals—including the potential impact of preceding syphilis episodes on subsequent syphilis risk.

Methods

In the prospective Swiss HIV cohort study, with routine syphilis testing since 2004, we analyzed HIV-infected men who have sex with men (MSM). Our primary outcome was first and repeated syphilis episodes. We used univariable and multivariable Andersen-Gill models to evaluate risk factors for first and repeated incident syphilis episodes.

Results

Within the 14-year observation period, we included 2513 HIV-infected MSM with an initially negative syphilis test. In the univariable and multivariable analysis, the number of prior syphilis episodes (adjusted hazard ratio [aHR] per 1-episode increase, 1.15; 95% confidence interval [CI], 1.01–1.31), having occasional sexual partners with or without condomless anal sex (aHR, 4.99; 95% CI, 4.08–6.11; and aHR, 2.54; 95% CI, 2.10–3.07), and being currently on antiretroviral therapy (aHR, 1.62; 95% CI, 1.21–2.16) were associated with incident syphilis.

Conclusions

In HIV-infected MSM, we observed no indication of decreased syphilis risk with repeated syphilis episodes. The extent of sexual risk behavior over time was the strongest risk factor for repeated syphilis episodes. The observed association of antiretroviral therapy with repeated syphilis episodes warrants further immunological and epidemiological investigation.

High polymorphism rates in well-known T cell epitopes restricted by protective HLA alleles during HIV infection are associated with rapid disease progression in early-infected MSM in China

T cell epitopes restricted by several protective HLA alleles, such as B*57, B*5801, B*27, B*51 and B*13, have been very well defined over the past two decades. We investigated 32 well-known T cell epitopes restricted by protective HLA molecules among 54 Chinese men who have sex with men (MSM) at the early stage of HIV-1 infection. Subjects in our cohort carrying protective HLA types did not exhibit slow CD4 T cell count decline (P = 0.489) or low viral load set points (P = 0.500). Variations occurred in 96.88% (31/32) of the known wild-type epitopes (rate 1.85-100%), and the variation rates of the strains of two CRF01_AE lineages were significantly higher than those of non-CRF01_AE strains (76.82% vs. 48.96%, P = 0.004; 71.27% vs. 8.96%, P = 0.025). Subjects infected with CRF01_AE exhibited relatively rapid disease progression (P = 0.035). Therefore, the lack of wild-type protective T cell epitopes restricted by classic protective HLA alleles in CRF01_AE HIV-1 strains may be one of the reasons why rapid disease progression is observed in Chinese MSM with HIV-1 infection.

Meta-Analysis of The Prevalence of Genital Infections Among Hiv Carriers and Uninfected Women

Background & Aim:

The risk factors in acquiring genital co-infections associated with HIV infection still present many questions. We conducted a systematic review and meta-analysis to compare the prevalence of genital infection among HIV-infected and uninfected women.

Methods:

We searched PubMed, Web of Science, Scopus and Scielo for the relevant studies up until October 2017. Data were collected from the included studies and methodologically assessed. Odds ratios (OR) and 95% confidence intervals (CI) were pooled using fixed or random-effects models.

Results:

Thirty-six articles involving 23,863 women with retroviruses were included. HIV-infected women were significantly more diagnosed with the following genital infections:Herpes simplexvirus type 2 (HSV-2) (OR 3.70; 95% CI: 2.42–5.65),Neisseria gonorrhoeae(GC) (OR 4.18; 95% CI: 2.15-8.13),Chlamydia trachomatis(CT) (OR 2.25; 95% CI: 1.20-4.23) and Human papillomavirus (HPV) (OR 3.99, 95% CI: 3.35-4.75). There was no significant difference in the prevalence of bacterial vaginosis (OR 1.09; 95% CI: 0.91-1.30),Candida sp. (OR 1.51; 95% CI: 0.71-3.25),Treponema pallidum(OR 1.56; 95% CI: 1.00-2.45) andTrichomonas vaginalis(OR 1.00; 95% CI: 0.47-2.15).

Conclusion:

The prevalence of HPV, HSV-2, GC and CT genital infection was significantly higher among HIV-positive women.

Increasing incidence of syphilis among patients engaged in HIV care in Alberta, Canada: a retrospective clinic-based cohort study

BACKGROUND

Syphilis is a global health concern disproportionately affecting HIV-infected populations. In Alberta, Canada, the incidence of syphilis in the general population has recently doubled with 25% of these infections occurring in HIV-infected patients. The Southern Alberta HIV Clinic (SAC) and Calgary STI Program (CSTI) analyzed the epidemiologic characteristics of incident syphilis infections in our well-defined, HIV-infected population over 11 years.

METHODS

Since 2006, as routine practice of both the Southern Alberta Clinic (SAC) and Calgary STI Programs (CSTI), syphilis screening has accompanied HIV viral load measures every four months. All records of patients who, while in HIV care, either converted from being syphilis seronegative to a confirmed seropositive or were re-infected as evidenced by a four-fold increase in rapid plasma reagin (RPR) after past successful treatment, were reviewed.

RESULTS

Incident syphilis was identified 249 times in 194 HIV-infected individuals. There were 36 individuals with repeated infections (28.5% of episodes). Following a prior decline in annual incident syphilis rates, the rates have tripled from 8.08/1000 patient-years (95% confidence interval (CI): 4.14-14.75) in 2011, to 27.04 per 1000 person-years (95% CI: 19.45-36.76) in 2016. Half of the syphilis episodes were asymptomatic. Patients diagnosed with syphilis were twice as likely not to be taking ART and had a higher likelihood of having plasma HIV RNA viral loads > 1000 copies/mL (19%). Incident syphilis was seen predominantly in Caucasians (72%, P < 0.001), males (94%, P < 0.001) and men who have sex with men (MSM) as their HIV risk activity (75%, P < 0.001).

CONCLUSIONS

We have highlighted the importance of a regular syphilis screening program in HIV-infected individuals demonstrated by increasing rates of incident syphilis in our region. Targeted preventative strategies should be directed towards HIV-infected populations identified at highest risk, including; MSM, prior alcohol abuse, prior recreational drug use and those with prior syphilis diagnoses.

A double-edged sword: does highly active antiretroviral therapy contribute to syphilis incidence by impairing immunity to Treponema pallidum?

BACKGROUND AND HYPOTHESIS

Recently, the world has experienced a rapidly escalating outbreak of infectious syphilis primarily affecting men who have sex with men (MSM); many are taking highly active antiretroviral therapy (HAART) for HIV-1 infection. The prevailing hypothesis is that HAART availability and effectiveness have led to the perception among both individuals who are HIV-1 infected and those who are uninfected that HIV-1 transmission has become much less likely, and the effects of HIV-1 infection less deadly. This is expected to result in increased sexual risk-taking, especially unprotected anal intercourse, leading to more non-HIV-1 STDs, including gonorrhoea, chlamydia and syphilis. However, syphilis incidence has increased more rapidly than other STDs. We hypothesise that HAART downregulates the innate and acquired immune responses to Treponema pallidum and that this biological explanation plays an important role in the syphilis epidemic.

METHODS

We performed a literature search and developed a mathematical model of HIV-1 and T. pallidum confection in a population with two risk groups with assortative mixing to explore the consequence on syphilis prevalence of HAART-induced changes in behaviour versus HAART-induced biological effects.

CONCLUSIONS AND IMPLICATIONS

Since rising syphilis incidence appears to have outpaced gonorrhoea and chlamydia, predominantly affecting HIV-1 positive MSM, behavioural factors alone may be insufficient to explain the unique, sharp increase in syphilis incidence. HAART agents have the potential to alter the innate and acquired immune responses in ways that may enhance susceptibility to T. pallidum. This raises the possibility that therapeutic and preventative HAART may inadvertently increase the incidence of syphilis, a situation that would have significant and global public health implications. We propose that additional studies investigating the interplay between HAART and enhanced T. pallidum susceptibility are needed. If our hypothesis is correct, HAART should be combined with enhanced patient management including frequent monitoring for pathogens such as T. pallidum.

The tradition algorithm approach underestimates the prevalence of serodiagnosis of syphilis in HIV-infected individuals

Currently, there are three algorithms for screening of syphilis: traditional algorithm, reverse algorithm and European Centre for Disease Prevention and Control (ECDC) algorithm. To date, there is not a generally recognized diagnostic algorithm. When syphilis meets HIV, the situation is even more complex. To evaluate their screening performance and impact on the seroprevalence of syphilis in HIV-infected individuals, we conducted a cross-sectional study included 865 serum samples from HIV-infected patients in a tertiary hospital. Every sample (one per patient) was tested with toluidine red unheated serum test (TRUST), T. pallidum particle agglutination assay (TPPA), and Treponema pallidum enzyme immunoassay (TP-EIA) according to the manufacturer's instructions. The results of syphilis serological testing were interpreted following different algorithms respectively. We directly compared the traditional syphilis screening algorithm with the reverse syphilis screening algorithm in this unique population. The reverse algorithm achieved remarkable higher seroprevalence of syphilis than the traditional algorithm (24.9% vs. 14.2%, p < 0.0001). Compared to the reverse algorithm, the traditional algorithm also had a missed serodiagnosis rate of 42.8%. The total percentages of agreement and corresponding kappa values of tradition and ECDC algorithm compared with those of reverse algorithm were as follows: 89.4%,0.668; 99.8%, 0.994. There was a very good strength of agreement between the reverse and the ECDC algorithm. Our results supported the reverse (or ECDC) algorithm in screening of syphilis in HIV-infected populations. In addition, our study demonstrated that screening of HIV-populations using different algorithms may result in a statistically different seroprevalence of syphilis.

Factors associated with syphilis incidence in the HIV-infected in the era of highly active antiretrovirals

After several years of steady decline, syphilis is reemerging globally as a public health hazard, especially among people living with human immunodeficiency virus (HIV). Syphilis resurgence is observed mainly in men who have sex with men (MSM), yet other transmission groups are affected too. In this manuscript, we study the factors associated with syphilis incidence in the Swiss HIV cohort study in the era of highly effective antiretrovirals. Using parametric interval censored models with fixed and time-varying covariates, we studied the immunological, behavioral, and treatment-related elements associated with syphilis incidence in 3 transmission groups: MSM, heterosexuals, and intravenous drug users. Syphilis incidence has been increasing annually since 2005, with up to 74 incident cases per 1000 person-years in 2013, with MSM being the population with the highest burden (92% of cases). While antiretroviral treatment (ART) in general did not affect syphilis incidence, nevirapine (NVP) was associated with a lower hazard of syphilis incidence (multivariable hazard ratio 0.5, 95% confidence interval 0.2-1.0). We observed that condomless sex and younger age were associated with higher syphilis incidence. Moreover, time-updated CD4, nadir CD4, and CD8 cell counts were not associated with syphilis incidence. Finally, testing frequency higher than the recommended once a year routine testing was associated with a 2-fold higher risk of acquiring syphilis. Condomless sex is the main driver of syphilis resurgence in the Swiss HIV Cohort study; ART and immune reconstitution provide no protection against syphilis. This entails targeted interventions and frequent screening of high-risk populations. There is no known effect of NVP on syphilis; therefore, further clinical, epidemiological, and microbiological investigation is necessary to validate our observation.

Incidence and Risk Factors for Incident Syphilis among HIV-1-Infected Men Who Have Sex with Men in a Large Urban HIV Clinic in Tokyo, 2008-2015

Background

The epidemiology of incident syphilis infection among HIV-1-infected men who have sex with men (MSM) largely remains unknown.

Methods

The incidence and risk factors for incident syphilis (positive TPHA and RPR> = 1:8) among HIV-1-infected MSM who visited a large HIV clinic in Tokyo for the first time between 2008 and 2013 were determined, using clinical data and stored blood samples taken every three months for screening and determination of the date of incident syphilis. Poisson regression compared the incidence of syphilis at different observation periods.

Results

Of 885 HIV-1-infected MSM with baseline data, 34% either presented with active syphilis at baseline (21%) or became infected with syphilis during follow-up (13%). After excluding 214 patients (MSM with syphilis at baseline (n = 190) and no follow-up syphilis test (n = 24)), of 671 men, 112 (17%) developed incident syphilis with an incidence of 43.7/1,000 person-years [95% CI, 36.5–52.3]. The incidence decreased slightly during observation period although the trend was not significant (2008–2009: 48.2/1,000 person-years, 2010–2011: 51.1/1,000 person-years, 2012–2013: 42.6/1,000 person-years, 2014 to 2015: 37.9/1,000 person-years, p = 0.315). Multivariable analysis identified young age (<33 years versus >40, HR 4.0, 95%CI 2.22–7.18, p<0.001), history of syphilis at baseline (HR 3.0, 95%CI 2.03–4.47, p<0.001), positive anti-amoeba antibody (HR 1.8, 95%CI 1.17–2.68, p = 0.006), and high baseline CD4 count (CD4 ≥350 /μL versus CD4 <200, HR 1.6, 95%CI 1.00–2.53, p = 0.050) as risk factors for incident syphilis. Incidence of syphilis was particularly high among young patients (age <33 years: 60.1/1,000 person-years). Interestingly, 37% of patients with incident syphilis were asymptomatic.

Conclusions

Although incidence of syphilis did not increase during the observation period, it was high among HIV-1-infected MSM, especially among young HIV-1-infected MSM and those with history of syphilis, in Tokyo. Regular screening for syphilis needs to be strictly applied to this population.

HIV and Syphilis Prevalence Among Transgender Women in Ho Chi Minh City, Vietnam

Globally, transgender women have higher risk for HIV than the general population and men who have sex with men, but there is little data on this population in Vietnam. In 2015 we conducted a biological and behavioral survey of 205 transgender women in Ho Chi Minh City, Vietnam. Factors associated with HIV and syphilis infection were assessed through multivariable logistic regression models. Median age was 25 years (range 18-64). Overall prevalence was 18.0 % for HIV and 17.6 % for syphilis. Factors independently associated with HIV infection included risky alcohol use [adjusted Odds Ratio (aOR) 3.55, 95 % confidence interval (CI) 1.53-8.21], amphetamine stimulant use (aOR 2.90, 95 % CI 1.27-6.61), sex with male sex workers (aOR 4.73, 95 % CI 1.72-13.0), and history of sex with an adult before the age of 18 years (aOR 2.97, 95 % CI 1.06-8.34). Two factors associated with syphilis infection were HIV infection (aOR 2.37, 95 % CI 1.03-5.45) and condomless anal sex with casual partners (aOR 2.27, 95 % CI 1.03-5.00). In order to address the HIV and syphilis epidemics in Vietnamese transgender women, interventions are needed to make HIV and sexually transmitted infection screening and treatment more accessible.

Prevalence and Determinants of Herpes Simplex Virus Type 2 (HSV-2)/Syphilis Co-Infection and HSV-2 Mono-Infection among Human Immunodeficiency Virus Positive Men Who Have Sex with Men: a Cross-Sectional Study in Northeast China

This study assessed the prevalence and determinants of herpes simplex virus type 2 (HSV-2)/syphilis co-infection and HSV-2 mono-infection in human immunodeficiency virus (HIV)-positive men who have sex with men (MSM) in China. A cross-sectional study was conducted of 545 HIV-positive MSM in Shenyang between February 2009 and October 2014. Participants underwent physical examinations and serological tests for HSV-2 and syphilis. A multinomial logistic regression was used to identify the risk factors associated with HSV-2/syphilis co-infection and HSV-2 mono-infection. The prevalence of HSV-2 mono-infection, syphilis mono-infection, and HSV-2/syphilis co-infection (95% confidence interval) was 48.6% (44.4-52.8%), 34.3% (30.3-38.3%), and 22.9% (19.4-26.5%), respectively. After controlling within HSV-2/syphilis-seropositive cases, regression analysis revealed that the related factors for HSV-2/syphilis co-infection included age (25-50 vs. ≤ 24 years: adjusted odds ratio [aOR], 4.55; > 50 vs. ≤ 24 years: aOR, 43.02), having regular female sexual partner(s) in the past 6 months (aOR, 0.43), and age at first MSM experience (≤ 18 vs. > 18 years: aOR, 2.59) (all P < 0.05). The high prevalence of HSV-2 mono infection and HSV-2/syphilis co-infection in HIV-positive MSM indicates a high secondary HIV transmission risk. A campaign for detection and treatment of HSV-2 and syphilis is urgently required for HIV-positive MSM in China.

Syphilis on the rise: A prolonged syphilis outbreak among HIV-infected patients in Northern Greece

INTRODUCTION

Sexually transmitted diseases (STDs) are a major public health issue in Europe. Numerous outbreaks of syphilis have been described recently and an increased prevalence of high-risk sexual practices has raised concern about the transmission of HIV and other STDs. Similarly, an increase in sexually transmitted infections has been recorded in Northern Greece.

METHODS

This report describes a recent outbreak of syphilis in people living with HIV. The demographic, clinical, and serologic data of HIV patients diagnosed with syphilis were recorded and analyzed. Data on syphilis incidence from the general population was also compared to HIV patients' data.

RESULTS

Fifty-eight HIV-patients of the Infectious Diseases Unit of a tertiary hospital (5.2%) were diagnosed with syphilis during a three-year period (2008-2010). Highly active antiretroviral therapy (HAART) and coexistence of other STDs were independent predictors of syphilis (OR: 2.4, 95CI%: 1.26, 4.63, p=0.008; OR: 9.4, 95%CI: 4.49, 19.64, p<0.001, respectively). Origin from a country other than Greece (p=0.005), and homosexual contact (p=0.003), were separate risk factors for syphilis in the general population in the same area.

CONCLUSION

Diagnosis of a sexually transmitted disease in an HIV patient is a crucial clinical event that should trigger the clinician's suspicion for high-risk sexual behavior. Sexual health assessments should be a routine process for HIV patients.

Risky sexual networks and concentrated HIV epidemics among men who have sex with men in Wenzhou, China: a respondent-driven sampling study

Background

The high and continually increasing prevalence of human immunodeficiency virus (HIV) and other sexually transmitted diseases among men who have sex with men (MSM) in China underscores the critical importance of examining the exact sexual networks that result in HIV transmission, as well as HIV infection, using powerful sampling methods, such as respondent-driven sampling (RDS), to improve the sexual health of this population.

Methods

Using RDS, a cross-sectional study was conducted among MSM in Wenzhou, Zhejiang province, China from December 2013 to June 2014. The type of sex, numbers of anal sex partners, male oral sex partners and vaginal sex partners, condom use during each type of sex over the previous 6 months, prevention behaviors, risk perception, and the burdens of HIV and syphilis were investigated and analyzed.

Results

Of 424 MSM, a great number of them did anal sex, male oral sex, and vaginal sex during the previous 6 months, and weighted estimates for the prevalence that MSM did not conduct these sexual behaviors were 11.2 % (95 % confidence interval [CI] =6.7–16.50 %), 20.3 % (95 % CI = 15.2–27.1 %), and 58.9 % (95 % CI = 52.1–65.8 %), respectively. Multiple sexual partners, engaging in regular, casual and commercial sex, and lack of condom use during all types of sex were common among MSM. The estimated HIV and syphilis prevalences were 22.8 % (95 % CI = 16.9–28.5 %) and 9.7 % (95 % CI = 6.4–13.6 %), respectively. Of the participants, 53.5 % (95 % CI = 45.3–60.2 %) received HIV-related interventions during the previous year, 48.1 % (95 % CI = 39.7–55.1 %) had never been tested for HIV, and only 14.1 % (95 % CI =10.1–19.2 %) perceived a risk of contracting HIV. Multiple logistic regression analysis revealed that age over 44 years (adjusted odds ratio [AOR] = 3.60, 95 % CI = 1.34–9.64), a monthly income of 3001–4000 yuan (approximately 470–630 US$) (AOR = 1.96, 95 % CI = 1.67–3.60), multiple anal sex partners (AOR = 1.93, 95 % CI = 1.15–3.24), awareness of the possibility of contracting HIV (AOR = 3.18, 95 % CI = 1.56–6.48), and current syphilis infection (AOR = 3.01, 95 % CI = 1.44–6.29) were predictors of HIV infection.

Conclusions

HIV transmission has become highly prevalent and will likely become more prevalent among MSM and their female partners if these risky sexual networks persist. Our findings call for urgent and effective interventions to prevent the rapid transmission of HIV among MSM in Wenzhou.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2591-7) contains supplementary material, which is available to authorized users.

Serum TRSUT Titer ≥1: 16 Is a Predictor for Neurosyphilis Among HIV-Infected Patients With Concurrent Syphilis and No Neurological Symptoms

Investigating the predictors for lumbar puncture to diagnose the asymptomatic neurosyphilis among HIV and syphilis co-infected patients in Shanghai, China. Respectively, screening the medical records from August 1, 2009 to June 30, 2015. Those HIV-infected patients with concurrent syphilis who had received lumbar puncture were selected and their clinical and demographic data were recorded. Participants comprised symptomatic and asymptomatic patients. The latter ones could be further divided into 3 groups: late syphilis, early syphilis with anti-syphilis treatment failure, and early syphilis with serum toludine red unheated serum test (TRUST) ≥1:32. Both syphilis stage and anti-syphilis treatment effect were defined by common criteria, and syphilis of unknown duration was considered as late syphilis. Asymptomatic neurosyphilis was defined as neurosyphilis without neurological symptoms such as headache, cognitive dysfunction, motor deficits, auditory or ophthalmic abnormalities, and stroke. Neurosyphilis was defined as reactive cerebrospinal fluid (CSF) TRUST and/or CSF white blood cell >20 cells/μL without other reasons. Mann-Whitney test and Fisher's exact test were used for analyzing the difference between neurosyphilis and non-neurosyphilis group. Logistic regression test was performed to analyze the risk factors for neurosyphilis. In total, 170 participants were collected, and the rate of neurosyphilis was 32.35%. Among all the 105 participants without neurological symptoms, 80 patients were with late syphilis and 25 were with early syphilis. Among the early syphilis patients, 23 had a TRUST ≥1:32 and the other 2 experienced an anti-syphilis treatment failure. The differences of clinical and demographic variables between neurosyphilis and non-neurosyphilis group were not statistically significant except the serum TRUST titer (P < 0.01). From HIV/syphilis co-infected patients with or without neurological symptom, those who had neurological symptoms, CD4 <350 per μL and serological TRUST titer ≥1:16 were 4.9-fold (95% confidence interval [CI]: 2.37-10.31), 4.3-fold (95% CI: 1.17-15.78), and 4.1-fold (95% CI: 1.58-10.76), respectively, more likely to be diagnosed with neurosyphilis. Asymptomatic patients whose serum TRUST titer ≥1:16 were 8.48-fold (95% CI: 1.08-66.63) more likely to have asymptomatic neurosyphilis. Among asymptomatic HIV-infected patients with late syphilis or early syphilis experienced an anti-syphilis treatment failure, those who have a serum TRUST titer ≥1:16 are suggested to perform lumbar puncture in order to avoid delayed diagnosis and the occurrence of severe sequelae of syphilis.