Go big or go home: impact of screening coverage on syphilis infection dynamics

Syphilis: recommendations for dermatologists on a resurgent epidemic

Despite reaching historical lows in the early 2000s, cases of both primary and secondary syphilis and congenital syphilis have increased dramatically in the U.S. over the last decade. In the U.S., the current syphilis epidemic is disproportionately impacting communities that have been historically underserved in medicine. These include men who have sex with men, especially those infected with HIV; people of color; and reproductive-age women with poor access to prenatal care. With syphilis now being more commonly diagnosed in non-STI than STI clinics in all genders, and since primary and secondary syphilis and congenital syphilis present with characteristic mucocutaneous manifestations, dermatologists are in a position to help reduce the advance of this preventable epidemic, by actively considering this diagnosis and incorporating syphilis screening into their practice. Herein, we delineate strategies by which dermatologists can contribute to this critical effort in their roles as clinicians, public health advocates, and researchers. In particular, we discuss the rapidly changing demographics of syphilis, nuances in serologic testing and treatment, strategies to increase public healthcare access and equity in these underserved populations, and research gaps in this field.

Community perspectives on ideal bacterial STI testing services for gay, bisexual, and other men who have sex with men in Toronto, Canada: a qualitative study

BACKGROUND

Innovation is needed to produce sustained improvements in bacterial sexually transmitted infections (STI) testing given suboptimal access and uptake among sexually active gay, bisexual or other men who have sex with men (GBM). Yet, the STI testing processes and technologies that best address local testing barriers among GBM in Toronto is unknown. We aimed to explore men's perspectives regarding STI testing services for GBM to identify and prioritize new STI testing interventions in Toronto, Ontario, Canada.

METHODS

We conducted four focus groups with twenty-seven GBM in 2017: two with cisgender men living with HIV, one with cisgender HIV-negative men, and one with transgender men. Twenty-seven men participated in the focus groups with 40% 18-30 years of age, 48% self-identifying as white, and the remainder self-identifying as Middle Eastern, Latino/Hispanic, Asian/Pacific Islander, South Asian, First Nations, African/Caribbean/Black, or mixed race. 59% of participants self-identified as living with HIV. Participants were asked about their STI testing experiences in Toronto, barriers and facilitators to testing, and ideal STI testing process. Focus groups were audio recorded, transcribed verbatim, and analyzed using thematic analysis.

RESULTS

Core concepts included how clinical context, bacterial STI testing delivery, and interactions with healthcare providers can create barriers and recommendations for ways to improve. Regarding clinical context, participants desired more clinics with accessible locations/hours; streamlined testing that minimized use of waiting rooms and wait times; and improved clinic ambience. Bacterial STI testing delivery recommendations included standardization to ensure consistency in sexual history intake, tests offered, follow-up and public health reporting between clinics. Men also recommended reducing the multistep process testing by offering components such as lab requisitions and results online. Participants also recommended interactions with healthcare providers be professional and non-judgmental, offer compassionate and competent care with destigmatizing and lesbian, gay, bisexual and trans (LGBT) affirming communication.

CONCLUSION

Concrete and practical solutions for improving existing sexual health services and facilitating optimal STI testing include streamlining testing options and providing patient-centred, LGBT-affirming care to enable optimal STI testing.

Sexually Transmitted Infections Among Men and Transgender Women Using HIV Pre-exposure Prophylaxis in a Large Integrated Health System-A Cohort Study

BACKGROUND

Sexually transmitted infections (STIs) are common in people using pre-exposure prophylaxis (PrEP). We examined risk and factors associated with STIs in a cohort of PrEP users in an integrated health system in the United States.

SETTING

The Kaiser Permanente Southern California is a large integrated health system that provides comprehensive medical services to approximately 4.7 million demographically diverse members.

METHODS

We identified men and transgender women initiating PrEP between January 1, 2014, and June 1, 2018, and followed through December 31, 2018. Demographic and clinical factors potentially associated with the risk of bacterial STIs during PrEP use were evaluated using Poisson regression models.

RESULTS

Among 5042 individuals tested for STIs with 7198 person-years of follow-up, 1709 (33.9%) had at least one new STI. The estimated incidence of STIs was 48.3 per 100 person-years, and the most common STI was rectal chlamydia. Most repeat STIs (61.4%) occurred <180 days apart. In a multivariable analysis, an history of STIs in the prior 6 months through 7 days after the PrEP initiation was the most prominent risk factor of STIs during PrEP use (adjusted risk ratio: 1.78, 95% confidence intervals: 1.65 to 1.93). Other risk factors included younger age (<35 years), being Hispanic, and having a history of alcohol use disorder or drug use disorder.

CONCLUSIONS

Quarterly STI testing and targeted intervention to mitigate STI risk are warranted for young and racial minority PrEP users, particularly for those with prior history of STIs and substance use disorders.

Cost-effectiveness of implementing HIV and HIV/syphilis dual testing among key populations in Viet Nam: a modelling analysis

OBJECTIVES

Key populations, including sex workers, men who have sex with men, and people who inject drugs, have a high risk of HIV and sexually transmitted infections. We assessed the health and economic impacts of different HIV and syphilis testing strategies among three key populations in Viet Nam using a dual HIV/syphilis rapid diagnostic test (RDT).

SETTING

We used the spectrum AIDS impact model to simulate the HIV epidemic in Viet Nam and evaluated five testing scenarios among key populations. We used a 15-year time horizon and a provider perspective for costs.

PARTICIPANTS

We simulate the entire population of Viet Nam in the model.

INTERVENTIONS

We modelled five testing scenarios among key populations: (1) annual testing with an HIV RDT, (2) annual testing with a dual RDT, (3) biannual testing using dual RDT and HIV RDT, (4) biannual testing using HIV RDT and (5) biannual testing using dual RDT.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome is incremental cost-effectiveness ratios. Secondary outcomes include HIV and syphilis cases.

RESULTS

Annual testing using a dual HIV/syphilis RDT was cost-effective (US$10 per disability-adjusted life year (DALY)) and averted 3206 HIV cases and treated 27 727 syphilis cases compared with baseline over 15 years. Biannual testing using one dual test and one HIV RDT (US$1166 per DALY), or two dual tests (US$5672 per DALY) both averted an additional 875 HIV cases, although only the former scenario was cost-effective. Annual or biannual HIV testing using HIV RDTs and separate syphilis tests were more costly and less effective than using one or two dual RDTs.

CONCLUSIONS

Annual HIV and syphilis testing using dual RDT among key populations is cost-effective in Vietnam and similar settings to reach global reduction goals for HIV and syphilis.

Management of Adult Syphilis: Key Questions to Inform the 2021 Centers for Disease Control and Prevention Sexually Transmitted Infections Treatment Guidelines

A panel of experts generated 5 "key questions" in the management of adult syphilis. A systematic literature review was conducted and tables of evidence were constructed to answer these questions. Available data suggest no clinical benefit to >1 dose of benzathine penicillin G for early syphilis in human immunodeficiency virus (HIV)-infected patients. While penicillin remains the drug of choice to treat syphilis, doxycycline to treat early and late latent syphilis is an acceptable alternate option if penicillin cannot be used. There are very limited data regarding the impact of additional antibiotic doses on serologic responses in serofast patients and no data on the impact of additional antibiotic courses on long-term clinical outcomes. In patients with isolated ocular or otic signs and symptoms, reactive syphilis serologic results, and confirmed ocular/otic abnormalities at examination, a diagnostic cerebrospinal fluid (CSF) examination is not necessary, because up to 40% and 90% of patients, respectively, would have no CSF abnormalities. Based on the results of 2 studies, repeated CSF examinations are not necessary for HIV-uninfected patients or HIV-infected patients on antiretroviral therapy who exhibit appropriate serologic and clinical responses after treatment for neurosyphilis. Finally, several important gaps were identified and should be a priority for future research.

A descriptive study of syphilis testing in Manitoba, Canada, 2015-2019

BACKGROUND

In 2018, Manitoba had the highest reported rate of infectious syphilis in Canada, at over three times the national average. Infectious syphilis in Manitoba is centred on young, marginalized heterosexual couples in Winnipeg's inner-city. Subsequently, a public health crisis involving congenital syphilis emerged in Manitoba, just prior to the coronavirus disease 2019 pandemic. Testing and screening (in the case of pregnancy) for syphilis is thought to be an effective measure to reduce the incidence of syphilis and its sequelae. The aim of this study is to describe syphilis testing practices in the general population and amongst pregnant women, during a period of shifting syphilis epidemiology.

METHODS

We used population-based syphilis testing data from Cadham Provincial Laboratory (Winnipeg, Manitoba) for 2015 to 2019. Directly age-standardized rates are reported, and Poisson regression used to model the determinants of testing rates. Rates of prenatal screening are also reported.

RESULTS

From 2015 to 2019, a total of 386,350 individuals were tested for syphilis. The rate increased annually, from 462 per 10,000 population in 2015 to 704 per 100,000 in 2019, while the female-to-male ratio decreased from 1.8 to 1.6. Prior to 2019, the majority of pregnant women (approximately 60%) were screened once, during the first trimester; however, 2019 saw more women having more than two tests during the course of their pregnancy.

CONCLUSION

An overall increase in the number of individuals tested was observed, reflecting the increased rate of syphilis in Manitoba. Prenatal screening patterns shifted in 2019, likely in response to rising congenital syphilis numbers.

Countering the rise of syphilis: A role for doxycycline post-exposure prophylaxis?

Doxycycline post-exposure prophylaxis (PEP) holds the potential to mitigate increasing rates of syphilis among sexual minority men (SMM) in the US yet has received limited attention. Since evaluation of this intervention in actual populations is not currently feasible, we used agent-based models (ABM) to assess the population-level impact of this strategy. We adapted ABM of HIV and HPV transmission, representing a population of 10,230 SMM in Philadelphia, Pennsylvania, US. Parameter inputs were derived from the literature, and ABM outputs during the pre-intervention period were calibrated to local surveillance data. Intervention scenarios varied doxycycline uptake by 20, 40, 60, 80 and 100%, while assuming continued condom use and syphilis screening and treatment. Under each intervention scenario, we incorporated treatment adherence at the following levels: 0, 20, 40, 60, 80 and 100%. Long-term population impact of prophylactic doxycycline was measured using the cumulative incidence over the 10-year period and the percentage of infections prevented attributable to doxycycline at year 10. An uptake scenario of 20% with an adherence level of 80% would reduce the cumulative incidence of infections by 10% over the next decade, translating to 57 fewer cases per 1000 SMM. At year 10, under the same uptake and adherence level, 22% of infections would be prevented due to doxycycline PEP in the instances where condoms were not used or failed. Findings suggest that doxycycline PEP will have a modest impact on syphilis incidence when assuming a reasonable level of uptake and adherence. Doxycycline PEP may be most appropriate as a secondary prevention measure to condoms and enhanced syphilis screening for reducing infections among SMM.

Sexually Transmitted Infections Treatment Guidelines, 2021

These guidelines for the treatment of persons who have or are at risk for sexually transmitted infections (STIs) were updated by CDC after consultation with professionals knowledgeable in the field of STIs who met in Atlanta, Georgia, June 11–14, 2019. The information in this report updates the 2015 guidelines. These guidelines discuss 1) updated recommendations for treatment of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis; 2) addition of metronidazole to the recommended treatment regimen for pelvic inflammatory disease; 3) alternative treatment options for bacterial vaginosis; 4) management of Mycoplasma genitalium; 5) human papillomavirus vaccine recommendations and counseling messages; 6) expanded risk factors for syphilis testing among pregnant women; 7) one-time testing for hepatitis C infection; 8) evaluation of men who have sex with men after sexual assault; and 9) two-step testing for serologic diagnosis of genital herpes simplex virus. Physicians and other health care providers can use these guidelines to assist in prevention and treatment of STIs.

Prevalence of syphilis among men who have sex with men: a global systematic review and meta-analysis from 2000-20

BACKGROUND

The WHO Global Health Sector Strategy aims to reduce worldwide syphilis incidence by 90% between 2018 and 2030. If this goal is to be achieved, interventions that target high-burden groups, including men who have sex with men (MSM), will be required. However, there are no global prevalence estimates of syphilis among MSM to serve as a baseline for monitoring or modelling disease burden. We aimed to assess the global prevalence of syphilis among MSM using the available literature.

METHODS

In this global systematic review and meta-analysis, we searched MEDLINE, Embase, LILACS, and AIM databases, and Integrated Bio-Behavioral Surveillance (IBBS) reports between April 23, 2019, and Feb 1, 2020, to identify studies done between Jan 1, 2000, and Feb 1, 2020, with syphilis point prevalence data measured by biological assay among MSM (defined as people who were assigned as male at birth and had oral or anal sex with at least one other man in their lifetime). Studies were excluded if participants were exclusively HIV-infected MSM, injection-drug users, only seeking care for sexually transmitted infections (STIs) or genital symptoms, or routine STI clinic attendees. Data were extracted onto standardised forms and cross-checked for accuracy and validity. We used random-effects models to generate pooled prevalence estimates across the eight regions of the Sustainable Development Goals. We calculated risk of study bias based on the Appraisal tool for Cross-Sectional Studies, and stratified results based on low versus high risk of bias. This systematic review and meta-analysis was registered with PROSPERO, CRD42019144594.

FINDINGS

We reviewed 4339 records, 228 IBBS reports, and ten articles from other sources. Of these, 1301 duplicate records were excluded, 2467 records were excluded after title and abstract screening, and 534 articles were excluded after full-text analysis. We identified 345 prevalence data points from 275 studies across 77 countries, with a total of 606 232 participants. Global pooled prevalence from 2000-20 was 7·5% (95% CI 7·0-8·0%), ranging from 1·9% (1·0-3·1%) in Australia and New Zealand to 10·6% (8·5-12·9%) in Latin America and the Caribbean.

INTERPRETATION

Unacceptably high syphilis prevalence among MSM warrants urgent action.

FUNDING

Wellcome Trust.

Routinised Syphilis Screening among Men Living with HIV: A stepped wedge cluster randomised controlled trial

BACKGROUND

Frequent syphilis screening may increase early detection and decrease transmission. We implemented an opt-out clinic-based intervention pairing syphilis tests with routine HIV viral load testing. The primary objective was to determine the degree to which this intervention increased the detection of early syphilis.

METHODS

The Enhanced Syphilis Screening among HIV-positive Men (ESSAHM) Trial was a stepped wedge cluster-randomised controlled trial involving four urban HIV clinics in Ontario, Canada, from 2015 to 2017. Population: HIV-positive adult males. Intervention (I): standing orders for syphilis serological testing with viral loads. Control (C): usual practice. Outcome: early syphilis diagnosis. We obtained test results via linkage with the centralized provincial laboratory and defined cases using a standardized clinical worksheet and medical chart review. We employed a generalized linear mixed model with a logit link to estimate odds ratios (OR) and 95% confidence intervals (CI) of the intervention.

FINDINGS

3,895 men were followed over 7,471 person-years (PY). The mean number of syphilis tests increased from 0.53 to 2.02 tests per person per year. There were 217 new diagnoses of syphilis (C: 81; I: 136), for which 147 (68%) were cases of early syphilis (C:61 (75%); I:86 (63%)). The annualized proportion with newly-detected early syphilis increased from 0.009 to 0.032 with implementation of the intervention; the corresponding time-adjusted OR was 1.25 (CI 0.71, 2.20).

INTERPRETATION

The implementation of standing orders for syphilis testing with HIV viral loads was feasible and increased testing yet produced less-than-expected increases in case detection compared to past uncontrolled pre-post trials.

Sexually Transmitted Infection Screening Among Gay, Bisexual, and Other Men Who Have Sex With Men Prescribed Pre-exposure Prophylaxis in Baltimore City, Maryland

BACKGROUND

Human immunodeficiency virus pre-exposure prophylaxis (PrEP) clinical guidelines recommend men who have sex with men (MSM) PrEP users be screened biannually for syphilis and gonorrhea/chlamydia at all anatomic sites. We sought to determine the proportion screened and positive by STI and anatomic site at PrEP initiation and PrEP-care visits and patient-level characteristics associated with screening among MSM PrEP users in Baltimore City, Maryland.

METHODS

Medical records among MSM initiating PrEP between 30 September 2015 and 31 March 2018 were abstracted. STI screening (syphilis and gonorrhea/chlamydia at all anatomic sites) and positivity at PrEP visits ≤12 months following initiation were calculated. Poisson regression with cluster robust SEs was used to assess associations with STI screening.

RESULTS

Among 290 MSM initiating PrEP, 43.1% (n = 125) were screened per guidelines at PrEP initiation; 79.3% (230), 69.3% (201), 55.9% (162), and 69.3% (201) were screened for syphilis, urogenital, rectal, and oropharyngeal gonorrhea/chlamydia, respectively. Positivity among those screened was syphilis, 7.8% (n = 18/230); gonorrhea, 5.0% urogenital (10/201), 11.1% rectal (18/162), and 7.5% oropharyngeal (15/201); chlamydia, 5.0% urogenital (10/201), 11.7% rectal (19/162), and 1.5% oropharyngeal (3/201). Reported anal and oral sex (vs neither) was independently associated with STI screening (aPR, 2.11; 1.05-4.27) at PrEP initiation. At biannual PrEP-care visits, STI screening was lower and syphilis and rectal gonorrhea/chlamydia positivity was higher.

CONCLUSIONS

Observed STI screening levels and disease burden suggest the effectiveness of STI screening in PrEP care for STI prevention may be limited. Our results suggest providers may be offering screening based on sexual practices; clarification of STI screening guidelines for PrEP users is needed.

Exploring How Epidemic Context Influences Syphilis Screening Impact: A Mathematical Modeling Study

Transmission modeling suggests that screening guidelines focused on men who have sex with men are likely insufficient for syphilis control in contexts with substantial infection burden in heterosexual populations.

Supplemental digital content is available in the text.

The current syphilis epidemic in the United States is concentrated in gay, bisexual, and other men who have sex with men (MSM), but substantial heterosexual transmission is reported in some parts of the country. Using the US states of Louisiana and Massachusetts as case studies, we investigated how epidemic context influences the impact of population screening approaches for syphilis control.

Detection-Based Monetary Incentives to Improve Syphilis Screening Uptake: Results of a Pilot Intervention in a High Transmission Setting in Southern China

BACKGROUND

Underscreening of syphilis in clinical settings is a pervasive problem in resource-constrained settings where heavy patient loads and competing health priorities inhibit health providers' ability to meet screening coverage targets. A "detection-based" pay-for-performance (P4P) strategy can incentivize more targeted testing by rewarding providers with a monetary bonus for every confirmed case.

METHODS

Five clinics in a high transmission setting of China participated in the 6-month pilot intervention. Seropositive proportions during the P4P intervention were compared with those during the preintervention phase using multilevel logistic regression models adjusted for age and sex of clinic attendees.

RESULTS

There were 8423 patients that sought care at 1 of the 6 clinics over the course of the study. Adjusted odds of a positive syphilis screen were greater during the intervention period compared to the preintervention interval (odds ratio, 1.33; 95% confidence interval, 1.14-1.56). Variability in clinic-level effects was substantial given the small number of sites of this pilot study.

CONCLUSIONS

Results of this detection-based P4P pilot study demonstrate the feasibility and preliminary effectiveness of this approach for improving syphilis case detection in resource-constrained clinical settings. A fully powered randomized trial is needed to inform the full utility of this approach for improving sexually transmitted disease detection globally.

Modelling the impact of a sex work crackdown on syphilis transmission among female sex workers and their clients in South China

OBJECTIVE

To estimate the potential effects of an intense sex work crackdown on syphilis transmission in Guangdong Province, China.

METHODS

We developed a deterministic compartmental model of syphilis transmission among female sex workers (FSW) and their male clients in Guangdong Province, China. We based model assumptions on census data and scientific literature, and we fitted the model to sentinel surveillance estimates of syphilis prevalence (positive results in both treponemal and non-treponemal tests) among FSW between 2009 and 2013. We estimated the impact of an intense sex work crackdown in 2014 by comparing the number of new syphilis infections between 2014 and 2020 in crackdown versus basecase (no crackdown) scenarios. In modelling scenarios, we examined main crackdown mechanisms of impact, including changed number of FSW engaging in sex work, reduction of weekly transactions, condom usage rate and syphilis diagnosis rate.

RESULTS

In the basecase, predicted syphilis prevalence in FSW decreased from 2% in 2014 to 0.4% in 2020. In crackdown scenarios, syphilis incidence was predicted to transiently decrease and then to rebound relative to basecase levels a few years later. Shorter crackdowns led to higher, faster rebounds.

CONCLUSIONS

Short-term intense crackdowns may exacerbate syphilis transmission among FSW and further marginalise an already vulnerable group. This study provides a quantitative, infection-related basis for changing sex work policies to reduce harms.

Estimating the syphilis incidence and diagnosis rate in Japan: a mathematical modelling study

OBJECTIVES

The reported number of syphilis cases is increasing in Japan. In this study, we aimed to estimate both the incidence of infection and diagnosis-and-reporting rate using a mathematical model that captures the time course of infection.

METHODS

We analysed yearly notification data from 1961 to 2016 and stratified according to clinical stage and sex. We built a compartmental ordinary differential equations model to describe the natural epidemiological course of syphilis in which the incidence of infection and diagnosis-and-reporting rate were included as time-varying parameters that we estimated via the maximum likelihood method.

RESULTS

From 2008 to 2016, the estimated number of new syphilis cases among men and women was 1070 (95% CI 1037 to 1104) and 302 (95% CI 287 to 318), respectively, which was increased from the previous period (1999-2007) with 269 (95% CI 256 to 282) and 71 (95% CI 64 to 78) cases, respectively. The diagnosis-and-reporting rate did not vary greatly over time. We estimated the number of undiagnosed syphilis cases from either incubating or early clinical (ie, primary or secondary) infections in 2016 to be 262 (95% CI 249 to 275) and 79 (95% CI 74 to 84) for men and women, respectively.

CONCLUSIONS

The recent increase in reported cases of syphilis is owing to an increase in the number of infections. We found no evidence of time-dependent improvement in detection or reporting.

What could re-infection tell us about R0? A modeling case-study of syphilis transmission

Many infectious diseases can lead to re-infection. We examined the relationship between the prevalence of repeat infection and the basic reproductive number (R₀). First we solved a generic, deterministic compartmental model of re-infection to derive an analytic solution for the relationship. We then numerically solved a disease-specific model of syphilis transmission that explicitly tracked re-infection. We derived a generic expression that reflects a non-linear and monotonically increasing relationship between proportion re-infection and R₀ and which is attenuated by entry/exit rates and recovery (i.e. treatment). Numerical simulations from the syphilis model aligned with the analytic relationship. Re-infection proportions could be used to understand how far regions are from epidemic control, and should be included as a routine indicator in infectious disease surveillance.

Syphilis

Treponema pallidum subspecies pallidum (T. pallidum) causes syphilis via sexual exposure or via vertical transmission during pregnancy. T. pallidum is renowned for its invasiveness and immune-evasiveness; its clinical manifestations result from local inflammatory responses to replicating spirochaetes and often imitate those of other diseases. The spirochaete has a long latent period during which individuals have no signs or symptoms but can remain infectious. Despite the availability of simple diagnostic tests and the effectiveness of treatment with a single dose of long-acting penicillin, syphilis is re-emerging as a global public health problem, particularly among men who have sex with men (MSM) in high-income and middle-income countries. Syphilis also causes several hundred thousand stillbirths and neonatal deaths every year in developing nations. Although several low-income countries have achieved WHO targets for the elimination of congenital syphilis, an alarming increase in the prevalence of syphilis in HIV-infected MSM serves as a strong reminder of the tenacity of T. pallidum as a pathogen. Strong advocacy and community involvement are needed to ensure that syphilis is given a high priority on the global health agenda. More investment is needed in research on the interaction between HIV and syphilis in MSM as well as into improved diagnostics, a better test of cure, intensified public health measures and, ultimately, a vaccine.

Can enhanced screening of men with a history of prior syphilis infection stem the epidemic in men who have sex with men? A mathematical modelling study

OBJECTIVES

The aim of this study is to determine the transmission impact of using prior syphilis infection to guide a focused syphilis screening intervention among men who have sex with men (MSM).

METHODS

We parameterised a deterministic model of syphilis transmission in MSM to reflect the 2011-2015 syphilis outbreak in Winnipeg, Canada. Enhanced screening of 75% of men with prior syphilis every 3 months (A) was compared with distributing equivalent number tests to all MSM (B) or those with the highest partner number (C). We compared early syphilis incidence, diagnoses and prevalence after 10 years, relative to a base case of 30% of MSM screened annually.

RESULTS

Strategy A was expected to avert 52% of incident infections, 44% of diagnosed cases and reduce early syphilis prevalence by 89%. Strategy B had the least impact. Strategy C was most effective, averting 59% of incident cases. When screening frequency was semiannual or annual, strategy A was the most effective.

CONCLUSIONS

Enhanced screening of MSM with prior syphilis may efficiently reduce transmission, especially when identification of high-risk men via self-reported partner numbers or high-frequency screening is difficult to achieve.

Frequency and determinants of consistent STI/HIV testing among men who have sex with men testing at STI outpatient clinics in the Netherlands: a longitudinal study

Objectives

Men who have sex with men (MSM) are at highest risk for STIs and HIV infections in the Netherlands. However, official guidelines on STI testing among MSM are lacking. They are advised to test for STIs at least every six months, but their testing behaviour is not well known. This study aimed to get insight into the proportion and determinants of consistent 6-monthly STI testing among MSM testing at STI outpatient clinics in the Netherlands.

Methods

This study included longitudinal surveillance data of STI consultations among MSM from all 26 STI outpatient clinics in the Netherlands between 1 June 2014 and 31 December 2015. Multinomial logistic regression analysis was used to identify determinants of consistent 6-monthly testing compared with single testing and inconsistent testing. Determinants of time between consultations among men with multiple consultations were analysed using a Cox Prentice-Williams-Peterson gap-time model.

Results

A total of 34 605 STI consultations of 18 634 MSM were included. 8966 (48.1%) men had more than one consultation, and 3516 (18.9%) men tested consistently 6-monthly. Indicators of high sexual risk behaviour, including having a history of STI, being HIV positive and having more than 10 sex partners, were positively associated with both being a consistent tester and returning to the STI clinic sooner. Men who were notified by a partner or who reported STI symptoms were also more likely to return to the STI clinic sooner, but were less likely to be consistent testers, identifying a group of event-driven testers.

Conclusions

The proportion of consistent 6-monthly testers among MSM visiting Dutch STI outpatient clinics was low. Testing behaviour was associated with sexual risk behaviour, but exact motives to test consistently remain unclear. Evidence-based testing guidelines are needed to achieve optimal reductions in STI transmission in the future.

Increased incidence of syphilis in men who have sex with men and risk management strategies, Germany, 2015

In Germany, the number of reported syphilis cases increased between 11% and 22% per year between 2010 and 2014. We analysed syphilis surveillance data and data of four behavioural surveys on men who have sex with men (MSM) in Germany (2003, 2007, 2010, 2013) to assess if this rise is ongoing and to find possible explanations for it. Syphilis notifications increased in 2015 by 19% to a total of 6,834. This was mainly due to increasing notifications in MSM of all age groups in larger German cities. Data from the behavioural surveys on MSM in Germany showed a simultaneous increase of selective condom use as HIV-status-bases risk management strategy and the number of syphilis cases. MSM diagnosed with HIV reported condomless anal intercourse with non-steady partners more frequent than MSM not diagnosed with HIV or untested for HIV, but the latter also reported higher frequencies of this behaviour in the more recent surveys. Transmission in HIV-positive MSM probably plays an important, but not exclusive role, for the syphilis dynamics in Germany. A risk adapted routine screening for sexually active MSM and potentially innovative approaches to increase early screening and treatment of syphilis such as internet counselling, home sampling, home testing and broadening venue-based (rapid) testing, should be critically evaluated to effectively reduce syphilis infections.

Global challenges in human immunodeficiency virus and syphilis coinfection among men who have sex with men

INTRODUCTION

Syphilis and human immunodeficiency virus (HIV) coinfection disproportionately affects men who have sex with men (MSM), and the rate of coinfection has been increasing over the last decade. HIV and syphilis coinfection is particularly challenging because the infections interact synergistically thereby increasing the risk of acquisition and transmission as well as accelerating disease progression. Areas covered: This paper reviews and summarizes the epidemiology, pathogenesis, diagnosis, clinical management and prevention of HIV and syphilis coinfection among MSM. Expert commentary: Research does not support a different syphilis treatment for coinfected individuals; however, coinfection may warrant a recommendation for antiretroviral therapy. In order to reverse the epidemic of syphilis and HIV coinfection, there needs to be greater awareness, improved cultural sensitivity among health care providers, improved access to preventative services and increased screening for syphilis and HIV.