Chemoprophylaxis Is Likely to Be Acceptable and Could Mitigate Syphilis Epidemics Among Populations of Gay Men

Is doxycycline post-exposure prophylaxis being utilised in Germany? Insights from an online survey among German men who have sex with men

PURPOSE

Doxycycline post-exposure prophylaxis (Doxy-PEP) reduces the likelihood of Chlamydia and early syphilis by approximately two-thirds. Currently, data on the frequency of Doxy-PEP use in men who have sex with men (MSM) are limited. This study aimed to assess knowledge, attitude towards, and frequency of Doxy-PEP use among MSM in Germany.

METHODS

We conducted a national online survey in Germany from summer to fall 2023, recruiting MSM and transgender women. Participants were invited to complete the online survey through social media, online dating platforms, and print media advertisements with active recruitment and poster advertising in private practices, tertiary outpatient clinics, and MSM community events in Germany.

RESULTS

In total, 438 participants completed the survey and were included in the analysis, and 285 (65.1%) were living with the human immunodeficiency virus (HIV) or taking HIV-pre-exposure prophylaxis (PrEP). Overall, 170 participants (38.8%) had heard of Doxy-PEP, and 275 (62.8%) would consider taking it, but only 32 (7.3%) reported having ever taken Doxy-PEP. The most common reason for a negative attitude towards Doxy-PEP were apprehension about insufficient detailed information, and concerns about antibiotic resistance. Doxy-PEP users were more likely to be on HIV-PrEP, had a higher self-reported risk of bacterial sexually transmitted infections (STIs), and often had a history of bacterial STIs.

CONCLUSION

The study demonstrated high awareness and strong interest in Doxy-PEP among MSM in Germany, most of whom were living with HIV or taking HIV-PrEP; however, the actual usage of Doxy-PEP remains low in the summer and fall of 2023.

CDC Clinical Guidelines on the Use of Doxycycline Postexposure Prophylaxis for Bacterial Sexually Transmitted Infection Prevention, United States, 2024

No vaccines and few chemoprophylaxis options exist for the prevention of bacterial sexually transmitted infections (STIs) (specifically syphilis, chlamydia, and gonorrhea). These infections have increased in the United States and disproportionately affect gay, bisexual, and other men who have sex with men (MSM) and transgender women (TGW). In three large randomized controlled trials, 200 mg of doxycycline taken within 72 hours after sex has been shown to reduce syphilis and chlamydia infections by >70% and gonococcal infections by approximately 50%. This report outlines CDC's recommendation for the use of doxycycline postexposure prophylaxis (doxy PEP), a novel, ongoing, patient-managed biomedical STI prevention strategy for a selected population. CDC recommends that MSM and TGW who have had a bacterial STI (specifically syphilis, chlamydia, or gonorrhea) diagnosed in the past 12 months should receive counseling that doxy PEP can be used as postexposure prophylaxis to prevent these infections. Following shared decision-making with their provider, CDC recommends that providers offer persons in this group a prescription for doxy PEP to be self-administered within 72 hours after having oral, vaginal, or anal sex. The recommended dose of doxy PEP is 200 mg and should not exceed a maximum dose of 200 mg every 24 hours.Doxy PEP, when offered, should be implemented in the context of a comprehensive sexual health approach, including risk reduction counseling, STI screening and treatment, recommended vaccination and linkage to HIV PrEP, HIV care, or other services as appropriate. Persons who are prescribed doxy PEP should undergo bacterial STI testing at anatomic sites of exposure at baseline and every 3-6 months thereafter. Ongoing need for doxy PEP should be assessed every 3-6 months as well. HIV screening should be performed for HIV-negative MSM and TGW according to current recommendations.

Early adopters of doxycycline as post-exposure prophylaxis to prevent bacterial sexually transmitted infections in a real-world clinical setting

OBJECTIVES

Doxycycline as post-exposure prophylaxis (DoxyPEP) is a novel prevention approach which has demonstrated efficacy in preventing bacterial sexually transmitted infections (STIs) in men who have sex with men (MSM) and transgender women (TGW) including people who are living with HIV and those on HIV pre-exposure prophylaxis (PrEP). We evaluated patient knowledge and interest in DoxyPEP, as well as early adopters of its use.

METHODS

In 2023, patients presenting for HIV and STI services at a primary care and sexual health clinic were asked about DoxyPEP knowledge, interest and use. Bivariate and multivariate analyses were used to evaluate demographics and behaviours associated with these outcomes.

RESULTS

A total of n=421 people presented for care. Of these, 314 were MSM/TGW. Fifteen percent were Black/African-American, and 21% were Hispanic/Latino. A total of 50% of MSM/TGW had heard of DoxyPEP, 49% were interested and 18% reported prior DoxyPEP use. Having a history of STI infection ever (adjusted OR (aOR) 5.95, 95% CI 2.69 to 13.13) and in the past 12 months (aOR 2.99, 95% CI 1.56 to 5.72) were both associated with DoxyPEP use. Individuals who had ever used HIV PrEP had nearly three times the odds of ever taking DoxyPEP (aOR 2.88, 95% CI 1.56 to 5.30). There was no association between the use of DoxyPEP and race, ethnicity or HIV status.

CONCLUSIONS

Among MSM and TGW, there is already significant awareness, interest and use of DoxyPEP to prevent bacterial STIs. Public health efforts should focus on improving access and delivery of this STI prevention intervention to MSM and TGW.

The impact of socio-environmental factors on doxycycline post-exposure prophylaxis awareness in the US: a cross-sectional study

Background We investigated awareness and use of doxycycline post-exposure prophylaxis (doxyPEP) in the US. DoxyPEP has preventative benefits for bacterial STIs among people assigned male at birth. We considered how individual, interpersonal and social determinants of health, such as state-level LGBTQ equality, impact doxyPEP awareness. Methods We conducted an online snapshot cross-sectional survey in June 2023. Survey questions included demographics, sexual and substance use behaviours, and socio-environmental factors, and provided a short explanation of doxyPEP, with questions regarding prior awareness and use. Results Among a racially diverse sample of 196 participants (median age 33 years), 94% identified as cisgender men, 26% were aware of doxyPEP, whereas only 14 (7%) had ever used it. Factors significantly associated with awareness included being college educated (OR 2.50, 95% CI 1.09-5.74), a past year bacterial STI (OR 4.20, 95% CI 1.97-8.89), having discussed HIV pre-exposure prophylaxis with a health care provider (OR 3.88, 95% CI 1.99-7.57) and having taken HIV pre-exposure prophylaxis (OR 2.29, 95% CI 1.11-4.70). Socio-environmental factors associated with doxyPEP awareness included living in a large urban city (OR 2.14, 95% CI 1.12-4.10) and living in a state with higher levels of LGBTQ policy equality (OR 2.18, 95% CI 1.07-4.44). Conclusions Considering the disproportionate impact of bacterial STIs on men who have sex with men, especially those living in lower LGBTQ equality regions, such as the Southern US, our study emphasises how socio-environmental factors may limit awareness and uptake of novel biomedical approaches that have the potential to prevent morbidity and enhance sexual health.

Position statement of the German STI Society on the prophylactic use of doxycycline to prevent STIs (Doxy-PEP, Doxy-PrEP)

Over the past two decades, there has been a rise in the incidence of syphilis, particularly among men who have sex with men (MSM). This has sparked interest in studying the prophylactic use of doxycycline to prevent syphilis and other sexually transmitted infections (STIs), commonly referred to as Doxycycline Pre- or Post-Exposure Prophylaxis (Doxy-PrEP, Doxy-PEP). At the same time, demand from potential users for this preventive measure is increasing. Several randomized controlled trials have demonstrated that the prophylactic use of doxycycline in MSM and trans women using HIV pre-exposure prophylaxis (HIV-PrEP) or living with an HIV infection effectively reduces the risk of syphilis and chlamydia infections. At present, however, unresolved questions remain, particularly regarding implications of a broad implementation of prophylactic doxycycline to prevent STIs on tetracycline and other antimicrobial resistance in bacterial STIs, non-STI-related bacterial pathogens, and the microbiome. In response to the increasing demand and the challenge of balancing effectiveness, safety, and the risk of promoting antibiotic resistance, the German STI Society (DSTIG) has issued a position statement, providing specific recommendations regarding potential indications, criteria, and occasions for the use of doxycycline in STI prevention. These recommendations are based on current evidence and expert opinion.

Stellungnahme der Deutschen STI-Gesellschaft zur antibiotischen STI-Prophylaxe mit Doxycyclin (Doxy-PEP, Doxy-PrEP): Position Statement of the German STI Society on the Prophylactic Use of Doxycycline to Prevent STIs (Doxy-PEP, Doxy-PrEP)

Seit etwa zwei Jahrzehnten ist eine Zunahme der Syphilisinzidenz zu beobachten, insbesondere unter Männern, die Sex mit Männern haben (MSM). Diese Entwicklung hat zu einem wachsenden Interesse an Studien zur prophylaktischen Anwendung des Antibiotikums Doxycyclin zur Vermeidung von Syphilisinfektionen und anderen sexuell übertragbaren Infektionen (STI), international meist als Doxycyclin‐Prä‐ beziehungsweise Post‐Expositionsprophylaxe (Doxy‐PrEP, Doxy‐PEP) bezeichnet, geführt. Zugleich steigt die Nachfrage seitens potenzieller Nutzer nach dieser präventiven Maßnahme.

Mehrere randomisierte kontrollierte Studien haben gezeigt, dass die prophylaktische Anwendung von Doxycyclin bei MSM und Trans‐Frauen mit HIV‐PrEP‐Gebrauch oder bekannter HIV‐Infektion das Risiko einer Syphilis‐ und Chlamydien‐Infektion wirksam reduziert. Zum gegenwärtigen Zeitpunkt bestehen jedoch noch offene Fragen, insbesondere hinsichtlich der möglichen Auswirkungen einer breiten Anwendung der antibiotischen STI‐Prophylaxe mit Doxycyclin auf Tetrazyklin‐ und andere antimikrobielle Resistenzen bei bakteriellen STI, anderen bakteriellen Pathogenen und Bakterien des Mikrobioms.

Angesichts der steigenden Nachfrage und der Herausforderung, eine Abwägung zwischen Wirksamkeit, Sicherheit und dem Risiko der Förderung von Antibiotikaresistenzen vorzunehmen, hat die Deutsche STI‐Gesellschaft (DSTIG) die vorliegende Stellungnahme erarbeitet. Diese enthält spezifische Empfehlungen zu potenziellen Indikationen, Kriterien und Anlässen für den Einsatz von Doxycyclin zur Prävention von STI. Die Empfehlungen basieren auf aktuellen Studienergebnissen und der Meinung von Fachpersonen.

Potential impact of doxycycline post-exposure prophylaxis prescribing strategies on incidence of bacterial sexually transmitted infections

BACKGROUND

Doxycycline post-exposure prophylaxis (doxyPEP) reduces bacterial sexually transmitted infection (STI) incidence in people with HIV (PWH) or using HIV preexposure prophylaxis (PrEP). Given concerns about widespread antibiotic use, we identified doxyPEP prescribing strategies to minimize use while maximizing impact on STIs.

METHODS

We used electronic health records of gay and bisexual men (GBM), transgender women, and non-binary people assigned male sex at birth with ≥2 STI tests (chlamydia, gonorrhea, syphilis) at an LGBTQ-focused health center during 2015-2020. We defined 10 hypothetical doxyPEP prescribing strategies based on PrEP use, HIV status, or STI history. We estimated doxyPEP use and STI diagnoses averted in counterfactual scenarios in which people meeting prescribing criteria received doxyPEP, assuming STI rates during use would have been reduced by clinical trial efficacy estimates.

RESULTS

Among 10,546 individuals (94% GBM), rate of any STI was 35.9/100 person-years. Prescribing doxyPEP to all individuals would have averted 71% of STI diagnoses (number needed to treat for one year to avert one STI diagnosis, NNT = 3.9); prescribing to PrEP users/PWH (52%/12% of individuals) would have averted 60% of STI diagnoses (NNT = 2.9). Prescribing doxyPEP for 12 months after STI diagnosis would have reduced the proportion using doxyPEP to 38% and averted 39% of STI diagnoses (NNT = 2.4). Prescribing after concurrent or repeated STIs would have maximized efficiency (lowest NNTs) but prevented fewer STIs.

CONCLUSIONS

Prescribing doxyPEP to individuals with STIs, particularly concurrent or repeated STIs, could avert a substantial proportion of all STI diagnoses. The most efficient prescribing strategies are based on STI history rather than HIV status or PrEP use.

Factors Associated With Willingness to Use Daily Antibiotics as Sexually Transmitted Infection Prophylaxis Among HIV Preexposure Prophylaxis-Experienced Gay and Bisexual Men in Australia

BACKGROUND

Gay and bisexual men (GBM) who use HIV preexposure prophylaxis (HIV-PrEP) have high rates of bacterial sexually transmitted infections (STIs). The use of daily antibiotics as STI preexposure prophylaxis (STI-PrEP) may be appealing to GBM who are using or have previously used HIV-PrEP (HIV-PrEP-experienced) for the prevention of bacterial STIs.

METHODS

We examined willingness to use daily STI-PrEP among a cross-sectional sample of HIV-PrEP-experienced GBM in Australia who participated in an observational online cohort study from August 2018 to March 2020. Factors associated with willingness to use daily STI-PrEP were determined using bivariate and multivariate logistic regression.

RESULTS

Of the 1347 participants, half (54.3%) were willing to use daily STI-PrEP. Factors independently associated with greater willingness to use daily STI-PrEP included having >10 sexual partners in the last 6 months, using methamphetamine in the last 6 months, being more conscious about avoiding STIs, having a greater number of STIs since commencing HIV-PrEP, being willing to take HIV-PrEP for as long as they were at risk of acquiring HIV, and only using condoms when a sexual partner requested them. Conversely, factors associated with less willingness to use daily STI-PrEP included being university educated, using nondaily dosing regimens of HIV-PrEP, preferring event-driven HIV-PrEP, and being concerned about long-term HIV-PrEP adverse effects.

CONCLUSIONS

Sexually transmitted infection PrEP is likely to be appealing to many HIV-PrEP-experienced GBM, especially those who engage in activities associated with a higher risk of STI transmission. However, they are less likely to be willing to use STI-PrEP unless it aligns with their HIV-PrEP dosing regimen, suggesting that research into the safety and efficacy of alternative STI prophylaxis dosing options should be prioritized.

Awareness and willingness to accept syphilis chemoprophylaxis among men who have sex with men from three cities in China: a cross-sectional study

Background

The awareness and willingness to use doxycycline-based syphilis chemoprophylaxis among men who have sex with men (MSM) in China remain largely unknown.

Methods

We recruited MSM online from Nanjing, Wuhan and Changsha between August and October of 2021, collected data from online survey, analyzed their data using descriptive statistics, and constructed binary logistic regression for factors associated with awareness and willingness to use chemoprophylaxis for syphilis and HIV.

Results

Of 725 participants (44.0% of which resided in Nanjing, 37.7% in Changsha, and 18.3% in Wuhan), a majority were under 25 years of age; 62.2% had college degrees; 11.3% were HIV positive; and 5.10% had prior syphilis infection. Only 28.83% of participants had heard of syphilis chemoprophylaxis before. Odds of knowing syphilis chemoprophylaxis were higher in those who think it is necessary to have syphilis chemoprophylaxis versus those who think it is unnecessary (P = 0.002), and were higher in those whose acquaintance had chemoprophylaxis experience before (P < 0.001). Meanwhile, those who had no previous doxycycline using history, or had positive attitude were more likely to be willing to accept syphilis chemoprophylaxis (P = 0.009, P < 0.001). Over two-thirds (67.8%) of participants preferred the PEP mode in syphilis chemoprophylaxis, and side-effects of drugs remains their most worrying aspect.

Conclusions

We observed elevated interest in syphilis chemoprophylaxis in MSM in our investigational areas, indicating that the combination of HIV and syphilis chemoprophylaxis in China is promising.

Repeat Syphilis Among HIV-Infected Men in Florida and Louisiana 2000-2018: Implications for Screening Recommendations

Syphilis rates have continued to rise in the United States. Florida and Louisiana consistently report high numbers of cases. We evaluated rates of reinfection to see if frequent rescreening might lead to earlier treatment and prevent infections. All syphilis records of all stages for males and females aged 15-70 years from the Florida and Louisiana Departments of Health surveillance databases 2000-2018 were evaluated. The first episode of syphilis during this period was considered the initial diagnosis for each person. Demographics of cases and repeaters (individuals reported with two or more cases of syphilis) were examined. Percentages of syphilis cases from repeaters by year were calculated as were percentages from HIV+ males. During 2000-2018, 124,827 syphilis cases were reported from 107,405 individuals: 73,811 (68.7%) males; 33,594 (31.3%) females. There were 12,545 individuals (repeaters) with two or more syphilis diagnoses (n = 17,422 cases; range, 2-10). From 2010 to 2018, repeaters accounted for steadily increasing percentage of all syphilis reported: 2010 (11%), 2013 (16%), 2015 (20%), and 2018 (26%). Among HIV+ male cases the percentage from repeaters also increased: 2010 (28%), 2013 (35%), 2015 (42%), and 2018 (50%). In 2018, 19% of all cases (n = 2455) were from HIV+ males who had a previous syphilis diagnosis. Among HIV+ males diagnosed with syphilis in 2015, 34% had a repeat syphilis diagnosis within 3 years. Most syphilis diagnosed in Florida and Louisiana was among persons infected for the first time. However, some subgroups could possibly benefit from more frequent screening. Males living with HIV who had a prior syphilis diagnosis were at very high risk of repeat infection.

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.

Interest, Concerns, and Attitudes Among Men Who Have Sex With Men and Health Care Providers Toward Prophylactic Use of Doxycycline Against Chlamydia trachomatis Infections and Syphilis

BACKGROUND

Prophylactic administration of doxycycline is regarded as a potential new public health strategy to combat the rising rates of Chlamydia trachomatis infections and syphilis among men who have sex with men. We conducted a survey-based study to evaluate how community members and health care providers in Southern California would perceive doxycycline preexposure/postexposure prophylaxis (PrEP/PEP) to predict its acceptability and identify potential areas of concern.

METHODS

We conducted an online cross-sectional survey among community members who identify as men who have sex with men and health care providers with prescribing authority in Southern California to investigate the current attitudes toward doxycycline PrEP/PEP, including their willingness to accept. We analyzed the data using descriptive statistics and binary logistic regression.

RESULTS

Among 212 enrolled community member participants, 67.5% indicated they would take doxycycline PrEP/PEP if offered by their provider. Higher acceptability was significantly associated with several characteristics, including recent history of bacterial sexually transmitted infection diagnosis and current use of HIV PrEP. For health care providers, 89.5% of 76 enrolled participants expressed willingness to prescribe doxycycline PrEP/PEP to their patients if recommended by the Centers for Disease Control and Prevention, but only 43.4% were willing if not. Both community members and health care providers demonstrated high levels of concern toward possible drug resistance.

CONCLUSIONS

Doxycycline PrEP/PEP as a preventive strategy against chlamydial infections and syphilis would likely be accepted among community members and health care providers. Clear guidelines from public health officials and further clarification on the strategy's potential impact on developing drug resistance may be necessary to ensure successful implementation.

In Vitro Susceptibility of Treponema pallidum subsp. pallidum to Doxycycline

Doxycycline is regarded as an effective therapy for early syphilis, and there is increasing interest in using doxycycline for prophylaxis of this infection. However, the MIC of doxycycline for Treponema pallidum subsp. pallidum has not been reported previously. In this study, an in vitro culture system was utilized to determine that the MIC of doxycycline is 0.06 to 0.10 μg/ml for four strains of T. pallidum subsp. pallidum (Nichols, SS14, UW231B, and UW249B). The Nichols strain cultured in vitro with doxycycline was also tested for infectivity in rabbits, and the minimum bactericidal concentration (MBC) was found to be ≤0.1 μg/ml using this method. The low MIC and MBC values are consistent with the previously demonstrated clinical efficacy of doxycycline for the treatment of early syphilis. This study represents the first report of the in vitro susceptibility of T. pallidum to doxycycline, and the resulting information may be useful in the consideration of doxycycline for use in prevention of syphilis.

High Interest in Syphilis Pre-exposure and Post-exposure Prophylaxis Among Gay, Bisexual and Other Men Who Have Sex With Men in Vancouver and Toronto

BACKGROUND

We assessed the acceptability of doxycycline-based syphilis pre-exposure and post-exposure prophylaxis (PrEP/PEP) as well as human immunodeficiency virus (HIV) PrEP/PEP in gay, bisexual, and other men who have sex with men (gbMSM).

METHODS

We recruited gbMSM from Toronto and Vancouver sexually transmitted infection (STI) clinics during routine visits from June 2018 to August 2018. We analyzed data using descriptive statistics and constructed multivariable logistic regression models for willingness to use syphilis and HIV PrEP and PEP respectively.

RESULTS

Among 424 participants (56.4% Toronto, 43.6% Vancouver), median (interquartile range [IQR]) age was 31.0 years (26.0-39.0 years), 61.7% had completed postsecondary education and 54.4% were white. Median (IQR) number of male partners in the past 6 months was 6.0 (3.0-13.0), and 18.2% had 1 or more prior syphilis diagnosis. 60.1%/44.1% indicated willingness to use syphilis PEP/PrEP; 36.6% were unwilling to use either. Among HIV-negative participants, 74.0% and 75.2% were willing to use HIV PrEP and PEP, respectively. Most participants were familiar with antibiotic resistance (89.0%) and agreed that syphilis rates are rising in Canada (68.2%), but only 55.4% believed they were at risk for syphilis. Agreement with the latter statement was associated with willingness to use syphilis PrEP (adjusted odds ratio [aOR], 1.6; 95% confidence interval [95%CI], 1.0-2.5), as was previous/existing HIV PrEP use (aOR, 2.2; 95% CI, 1.1-4.3) and being "very concerned" about STI acquisition (aOR, 1.9; 95% CI, 1.0-3.4). Odds of being willing to use syphilis PEP were higher in Toronto versus Vancouver (aOR, 2.0; 95% CI, 1.2-3.4) and increased with the number of different STIs previously diagnosed (aOR, 1.4; 95% CI, 1.2,1.7).

CONCLUSIONS

There is considerable interest in syphilis PrEP/PEP in gbMSM attending Toronto/Vancouver STI clinics.

Perceptions of sexually transmissible infection pre-exposure prophylaxis: a qualitative study of high-risk gay and bisexual men in Sydney, New South Wales

Background Novel sexually transmissible infection (STI) prevention strategies are needed to combat increasing bacterial STI incidences alongside decreasing condom use among gay and bisexual men (GBM) in Australia. Sexually transmissible infection pre-exposure prophylaxis (STI-PrEP) using regular doxycycline is one such strategy that is the subject of ongoing research. However, a lack of qualitative data regarding the conceptualisation, perceived risks, perceived benefits and preferred dosing strategies of STI-PrEP may impede future research and implementation efforts.

METHODS

Semistructured in-depth interviews were conducted with 13 high-risk GBM residing in Sydney, Australia. Interviews were audio recorded, transcribed verbatim and then analysed thematically.

RESULTS

STI-PrEP was largely conceptualised using pre-existing knowledge of HIV-PrEP. The perceived benefits, including a reduced incidence of STIs, destigmatisation and a 'peace of mind', often outweighed the perceived risks, including side effects, antibiotic resistance and stigmatisation of consumers. A daily dosing regimen was preferred unanimously by participants when compared with event-driven or episodic strategies.

CONCLUSIONS

Participants of this study were cautiously optimistic regarding the concept of STI-PrEP. The findings suggest that, in addition to examining the effectiveness of STI-PrEP, future implementation studies should also focus on concerns regarding side effects and monitoring antibiotic resistance, as well as considering the acceptability and potential for stigmatisation of STI-PrEP consumers.

Doxycycline Prophylaxis for Bacterial Sexually Transmitted Infections

Bacterial sexually transmitted infections (STIs) have been increasing over the past 2 decades in gay, bisexual, and other men who have sex with men. With the widespread use of early human immunodeficiency virus (HIV) treatment, which virtually eliminates transmission risk, and the availability of HIV pre-exposure prophylaxis, there have been attitudinal changes regarding HIV infection with resultant increases in sexual contact and declines in condom use. Doxycycline is used for primary prophylaxis in a number of infectious diseases. We conducted a state-of-the-art review to examine the current state of research, knowledge gaps, and challenges around the use of doxycycline prophylaxis to prevent syphilis and other STIs. International academic and government experts met in March 2019 to frame the initial inquiry, which was supplemented by focused literature searches. Two small short-term randomized controlled trials examining doxycycline prophylaxis found high efficacy. Five additional clinical studies are underway or in development. Studies differed in design, population, outcomes, and safety measures. Doxycycline prophylaxis for bacterial STIs shows promise. Better and more robust data are needed on efficacy; target population; community acceptability; behavioral risk compensation; doxycycline dose, regimen, and formulation; long-term safety; antimicrobial resistance; cost-effectiveness; and risk-benefit.

Knowledge and attitudes of syphilis and syphilis pre-exposure prophylaxis (PrEP) among men who have sex with men in Vancouver, Canada: a qualitative study

OBJECTIVES

In British Columbia, Canada, syphilis is at record-high rates, with over 80% of cases in 2017 seen in gay, bisexual and other men who have sex with men (GBM). The syphilis epidemic is of particular concern for those living with HIV, since syphilis may lead to more serious complications in this population. We sought to explore syphilis-related knowledge and attitudes around biomedical prevention options for syphilis, with the goal of informing effective strategies to prevent syphilis.

DESIGN

We conducted a qualitative study consisting of in-depth, individual interviews from December 2016 to June 2017. Our interviews focused on participants' knowledge about syphilis and perceptions regarding syphilis pre-exposure prophylaxis (PrEP). Interviews were analysed using Grounded Theory.

PARTICIPANTS

Twenty-five GBM were interviewed (64% white; median age: 43 years), including men living with HIV and/or with a history of syphilis.

SETTING

Vancouver, British Columbia.

RESULTS

Five interrelated themes emerged. First, GBM were aware of the local syphilis epidemic. Second, syphilis-related knowledge differed according to syphilis and HIV serostatus. Third, competing ideas emerged regarding men's concerns about syphilis. While our participants expressed concern about getting syphilis, they also described the importance of sexual pleasure. Fourth, many participants said that syphilis was not perceived to be alarming; preventing HIV infection remained a primary concern for many. Finally, while syphilis PrEP was appealing to those living with HIV or a prior syphilis diagnosis, others were concerned about antibiotic resistance, cost and side effects.

CONCLUSIONS

Our participants organised their safer sex strategies around HIV, not syphilis. Although syphilis-related knowledge was relatively high among GBM living with HIV and those with a prior syphilis diagnosis, this knowledge did not appear to be related with safer sexual practices, such as increased condom use. This work highlights the importance of examining other potential prevention solutions, such as syphilis PrEP.

Sexually transmissible infection control programs for men who have sex with men - what will they look like in 2020?

The resurgence of sexually transmissible infections among men who have sex with men is a concern for sexual health. Traditional strategies have relied on the promotion of condom use, regular testing, treatment, and partner management. Future sexually transmissible infection control programs must combine current prevention methods with novel approaches that target the providers, patients, and mechanisms of health care delivery.

Epidemiology and prevention of sexually transmitted infections in men who have sex with men at risk of HIV

Since 2012, the increasingly widespread promotion and uptake of HIV treatment as prevention and pre-exposure prophylaxis in men who have sex with men has been associated with increased sexually transmitted infections (STIs). However, numbers of STI cases have been rising for more than 20 years and the introduction of biomedical HIV interventions cannot explain the majority of the rises in STIs. The increases appear to have occurred mostly because of gradual changes in behaviour over many years, coupled in some settings with more condomless anal intercourse, and as a result of the increased screening for previously undetected asymptomatic infections. If control of STIs is to be improved, then a far greater emphasis on increased use of existing effective STI control strategies will be required, in addition to the investigation of new interventions. Central to effective STI control is accessible clinical care and screening services, which are currently inadequate in most settings. Insufficient action carries a risk of increased STI epidemics, including of newly resistant organisms.

Increased Syphilis Testing of Men Who Have Sex With Men: Greater Detection of Asymptomatic Early Syphilis and Relative Reduction in Secondary Syphilis

Background

Syphilis rates have increased markedly among men who have sex with men (MSM) internationally. We examined trends in syphilis testing and detection of early syphilis among MSM in Australia.

Methods

Serial cross-sectional analyses on syphilis testing and diagnoses among MSM attending a national sentinel network of 46 clinics in Australia between 2007 and 2014.

Results

359313 clinic visits were included. The proportion of MSM serologically tested for syphilis annually increased in HIV-negative (48% to 91%; Ptrend < .0001) and HIV-positive MSM (42% to 77%; Ptrend < .0001). The mean number of tests per man per year increased from 1.3 to 1.6 in HIV-negative MSM (Ptrend < .0001) and from 1.6 to 2.3 in HIV-positive MSM (Ptrend < .0001). 2799 and 1032 syphilis cases were detected in HIV-negative and HIV-positive MSM, respectively. Among HIV-negative MSM, the proportion of infections that were early latent increased from 27% to 44% (Ptrend < .0001), while the proportion that were secondary decreased from 24% to 19% (Ptrend = .030). Among HIV-positive MSM, early latent infections increased from 23% to 45% (Ptrend < .0001), while secondary infections decreased from 45% to 26% (Ptrend = .0003). Among HIV-positive MSM, decreasing secondary syphilis correlated with increasing testing coverage (r = -0.87; P = .005) or frequency (r = -0.93; P = .001).

Conclusions

Increases in syphilis screening were associated with increased detection of asymptomatic infectious syphilis and relative falls in secondary syphilis for both HIV-positive and HIV-negative MSM nationally, suggesting interruption of syphilis progression.

Syphilis incidence in men who have sex with men with human immunodeficiency virus comorbidity and the importance of integrating sexually transmitted infection prevention into HIV care

INTRODUCTION

Syphilis continues to be a growing epidemic among men who have sex with men (MSM), particularly for those living with the human immunodeficiency virus (HIV). In 2016, MSM accounted for 80% of primary and secondary syphilis diagnoses in men in the United States; almost half of who were also HIV-infected. The synergistic relationship between HIV and syphilis has significant implications not only for HIV patient management, but also for sexually transmitted infection (STI) control among MSM. Areas covered: We review the literature on STI screening and treatment barriers at the patient-, provider-, and health system-levels, and present strategies to incorporate STI prevention into HIV care settings. Expert commentary: Integration of STI prevention into HIV care is paramount to stop the epidemic of not only syphilis, but also other curable STIs like gonorrhea and chlamydia. Although guidelines have been established for STI testing in HIV-infected MSM, screening rates continue to be lower than desired. Gonorrhea and chlamydia screening is below 50% in HIV-infected MSM; interventions that improve testing of those two infections must be implemented. For syphilis control, other additional strategies such as chemoprophylaxis should be considered given syphilis screening is above 50% in HIV-infected MSM.

Emerging trends and persistent challenges in the management of adult syphilis

There are an estimated 10.6 million incident cases of syphilis worldwide each year. We highlight some persistent challenges and emerging trends in the clinical management of syphilis with a particular focus on therapy, serology, diagnostics, and prevention. Decades after the introduction of penicillin, the optimal management of early syphilis continues to be a controversial topic, particularly in the setting of HIV co-infection. Similarly, the need for routine lumbar puncture in HIV co-infected asymptomatic persons is an unanswered question. Despite advances in both automation and point-of-care diagnostics, we continue to rely on indirect measures of disease activity to manage this infection. As syphilis rates in some populations continue to rise, novel and effective prevention strategies are needed.

Public health interventions to control syphilis

Syphilis control strategies are old, but interventions have changed and there is now a more scientific approach to evidence of effectiveness. We searched PubMed using 'syphilis control' to identify papers that measured the effectiveness of interventions. We also included novel approaches and comprehensive responses to outbreaks. Few papers used high-quality research methodology and fewer evaluated impact on prevalence or incidence; most assessed intermediate outcomes. Syphilis can often be controlled by a combination of case finding, treatment and education. However, outbreaks are unique and ongoing evaluation is needed to see if interventions are producing intended intermediate outcomes at reasonable costs.

Syphilis: a fresh look at an old foe

Syphilis remains a pressing public health problem globally across different populations including men who have sex with men and pregnant women. It is timely to review what international surveillance data tell us and the evidence behind public health interventions aimed at controlling syphilis. A reinvigorated response to the re-emergence of syphilis is required.

Syphilis transmission: a review of the current evidence

Syphilis remains widespread worldwide, with increasing rates among men who have sex with men. This paper reviews available evidence regarding syphilis transmission, including data on: sexual transmission (transmission probability per sexual partnership), vertical transmission, transmission via blood products and organ donation, and other rare modes of transmission. In addition, host susceptibility to syphilis infection is discussed. Syphilis screening and treatment, condoms and risk-reduction counselling and how they modify syphilis transmission dynamics are considered.

Trends in transfusion-transmissible infections among Australian blood donors from 2005 to 2010

BACKGROUND

Routine monitoring of trends in transfusion-transmissible infections (TTIs) is essential to maintaining and improving transfusion safety. Although periodic studies have been published there is no comprehensive trend analysis for TTIs in Australian donors. This study determined recent trends in TTIs for which testing is conducted in Australia and described key attributes of infected blood donors.

STUDY DESIGN AND METHODS

This is a retrospective analysis using data on donation testing for TTIs (2005-2010) from the national blood service donor database and data on postdonation interviews with TTI-positive donors (2008-2010) from a risk factor database incorporating responses to standardized interview questions. The study measured the prevalence and incidence of TTIs in Australia and assessed their time trends. Multivariate analysis of time trends was conducted using Poisson regression models.

RESULTS

Overall, the prevalence and incidence of TTIs in 2005 to 2010 remained low and steady. The prevalence of hepatitis C virus decreased (rate ratio [RR], 0.93; 95% confidence interval [CI], 0.89-0.97) and the prevalence of active syphilis increased (RR, 1.51; 95% CI, 1.15-1.99) significantly during the study period. Prevalence of TTIs among Australian blood donors was substantially lower than that in the general population and no unique risk factors were identified in test-positive blood donors when compared with the general population.

CONCLUSION

Both the prevalence and the incidence of TTIs in Australian blood donors remained low, with a steady or declining trend for most infections except active syphilis. The lower prevalence of TTIs in blood donors compared with the general population reflects the effectiveness of donor education and donor selection measures in Australia.

Will changes in gay men's sexual behavior reduce syphilis rates?

BACKGROUND

Reducing rates of partner change and increasing condom usage among gay men are obvious targets for potentially reducing syphilis transmission among gay men.

METHODS

We developed an agent-based stochastic model to examine syphilis transmission among a population of gay men, representative of gay men in Australia. This model was used to explore the potential impact of changes in sexual behavior over 1 month, 3 month, and indefinite time frames on syphilis epidemics.

RESULTS

Simulations of interventions showed that short-term reductions in rates of partner change and increased condom use would have negligible impact on the long-term trends of syphilis epidemics. If no interventions are introduced, then the model forecasts that the syphilis prevalence in the population could continue to rise, with an increase of 80% in the number of men infected with syphilis during the next decade. However, if changes in sexual behavior are maintained in the long-term, then syphilis epidemics can be mitigated. If condom use is sustained at 80% in partnerships that are HIV discordant or of unknown status, then the prevalence of syphilis is estimated to decrease by 9% over 10 years. Similarly, if partner acquisition rates decrease by 25%, then there will be a 22% reduction in syphilis prevalence.

CONCLUSIONS

Interventions promoting partner reduction or increased condom use would be ineffective in the short-term, and would have limited prospects for success in the long-term unless very large changes in behavior are sustained. Complementary social research indicates that such long-term changes in behavior are unlikely to be adopted, and therefore other intervention strategies need to be developed to reduce syphilis among gay men.

Increasing gay men’s testing rates and enhancing partner notification can reduce the incidence of syphilis

Background We sought to determine whether gay men would be willing to increase syphilis testing and partner notification, and assessed the possible epidemiological impact these changes might have in the Australian population. Methods: We conducted an online survey (n = 2306) and focus groups to determine whether interventions to increase testing for syphilis and enhanced partner notification are likely to be acceptable to gay men in Australia. An individual-based mathematical model was developed to estimate the potential population-level impact of changes in these factors. Results: Of all men surveyed, 37.3% felt they should test more frequently for sexually transmissible infections. Men who recent unprotected anal intercourse with casual partners and men who reported a higher number of partners were more likely to indicate a greater willingness to increase testing frequency. HIV-positive men were more likely to indicate that their frequency of syphilis testing was adequate, incorporated as part of their regular HIV monitoring. Lack of convenience was the main barrier reported. Partner notification was broadly acceptable, although perceived stigma presented a potential barrier. The mathematical model indicated that increasing testing rates would have a substantial impact on reducing rates of syphilis infection among gay men and partner notification would further reduce infections. Conclusions: Interventions promoting testing for syphilis among gay men and increases in partner notification may be acceptable to gay men and are likely to result in decreased infection rates. Rapid testing and modern communication technologies could strengthen these interventions, and have an impact on the syphilis epidemic.