Latent Class Analysis of Sexual Behaviours and Attitudes to Sexually Transmitted Infections Among Gay and Bisexual Men Using PrEP.

Gay and bisexual men (GBM) who use pre-exposure prophylaxis (PrEP) are at increased risk of sexually transmitted infections (STIs) compared to those who don't use PrEP. Since the implementation of PrEP in Australia, it is possible that attitudes towards STIs have shifted in line with changes in risk and transmission dynamics in the context of increased screening. As the extent to which GBM utilise STI prevention strategies likely depends on their attitudes towards STIs and STI prevention, the aims of this study were to use latent class analysis (LCA) to classify GBM using PrEP on the basis of their attitudes towards STIs and reported risk behaviours, and examine how these categorisations relate to risk of STI acquisition. 1225 GBM who were previously enrolled in a PrEP implementation study (The PrEPX Study) completed a survey focused on sexual behaviours and attitudes towards STIs 1 year post-study follow-up. Data on chlamydia, gonorrhoea and syphilis testing and positivity were available through a sentinel network of participating study clinics. Using LCA, participants were allocated into four classes; Class 1, "Some concern and lowest risk"; Class 2, "Low concern and lower risk"; Class 3, " High concern and higher risk"; and Class 4, "Low concern and highest risk". The majority (78%) of participants were classified into Class 3 or Class 4, two groups which were distinguished by highly disparate attitudes towards STIs but with a similar proportion of participants diagnosed with a bacterial STI in the last 12 months (48% and 57%, respectively). Findings suggest that attitudes towards STIs among GBM using PrEP in Australia vary considerably, and this will likely influence their receptivity to different STI prevention strategies.

Barriers and facilitators to pre-exposure prophylaxis among African migrants in high income countries: a systematic review.

Background The aim of this review is to explore acceptability, barriers, and facilitators to PrEP use among African migrants in high-income countries. METHODS: A systematic review was conducted to explore reasons that contribute to low PrEP uptake in this population. Three online databases, abstracts from key conferences and reference lists of relevant studies articles published between the 2 July 2018 and 3 March 2019 were searched. Narrative synthesis was performed on quantitative data and thematic synthesis was performed on qualitative data. RESULTS: Of 1779 titles retrieved, two cross-sectional studies (United States (US) (n = 1), United Kingdom (UK) (n = 1)) and six qualitative studies (US (n = 2), UK (n = 3), Australia (n = 1)) met inclusion criteria. PrEP acceptability was reported in one cross-sectional article and two qualitative articles. Cross-sectional studies measured acceptability and willingness to use PrEP; in one study, 46% of African migrant men found PrEP use acceptable, and following PrEP education, another study categorised 60% of participants as willing to use PrEP if it were cost-free. Qualitative studies reported mixed acceptability, with higher acceptability reported for serodiscordant couples. Barriers and facilitators to PrEP use were coded into five themes: cultural aspects of stigma; knowledge gap in health literacy; risks unrelated to HIV transmission; practical considerations for PrEP use; and the impact of PrEP use on serodiscordant couples. CONCLUSIONS: Several common barriers to PrEP use, including stigma, health literacy and risk perception and cost, were identified. Findings were limited by there being no published data on uptake. Additional work is needed to understand PrEP acceptability and uptake among African migrants.

Trends in Human Immunodeficiency Virus and Sexually Transmitted Infection Testing Among Gay, Bisexual, and Other Men Who Have Sex With Men After Rapid Scale-up of Preexposure Prophylaxis in Victoria, Australia.

OBJECTIVE: Scale-up of human immunodeficiency virus (HIV) preexposure prophylaxis (PrEP) has raised concerns regarding its impact on clinic capacity and access to HIV testing. We describe enrolment in PrEPX, a large PrEP implementation study in Victoria, Australia, and the impact of PrEP uptake and maintenance on existing health services. METHODS: We describe enrolment between July 26, 2016, and March 31, 2018, and trends in HIV testing among PrEPX participating and nonparticipating gay and bisexual and other men who have sex with men (GBM) at 5 study clinics participating in a sentinel surveillance system (ACCESS). We evaluated HIV and STI testing trends using segmented linear regression across the prestudy (January 2015 to June 2016) and PrEPX study (July 2016 to March 2018) periods. FINDINGS: There were 2,049 individuals who registered interest in study participation: 72% enrolled into the study. Study clinics enrolled participants rapidly; of 4265 people enrolled in PrEPX (98% GBM), 1000 enrolled by week 3, 88% (n = 876) of whom enrolled at ACCESS sites.Prestudy period HIV testing rates were increasing at all ACCESS sites. In the month PrEPX commenced, there was an additional 247 HIV tests among PrEPX participants (P < 0.01) and no significant change among non-PrEPX GBM (P = 0.72). Across the study period, HIV testing increased by 7.2 (P < 0.01) and 8.9 (P < 0.01) tests/month among PrEPX participants and non-PrEPX GBM, respectively. The HIV testing increased among non-PrEPX GBM at sexual health clinics (18.8 tests/month, P < 0.01) and primary care clinics (7.9 tests/month, P < 0.01). Similar trends were observed across testing for all measured STIs. CONCLUSIONS: Rapid PrEP scale-up is possible without a reduction in HIV testing among GBM not using PrEP.

Association of HIV Preexposure Prophylaxis With Incidence of Sexually Transmitted Infections Among Individuals at High Risk of HIV Infection.

Importance: Emerging evidence suggests that risk of bacterial sexually transmitted infections (STIs) increases among gay and bisexual men following initiation of HIV preexposure prophylaxis (PrEP). Objective: To describe STI incidence and behavioral risk factors among a cohort of predominantly gay and bisexual men who use PrEP, and to explore changes in STI incidence following PrEP commencement. Design, Setting, and Participants: The Pre-exposure Prophylaxis Expanded (PrEPX) Study, a multisite, open-label intervention study, was nested within the Australian Collaboration for Coordinated Enhanced Sentinel Surveillance (ACCESS) clinic network. A total of 4275 participants were enrolled (July 26, 2016-April 1, 2018) in Victoria, Australia. Of these, 2981 enrolled at 5 ACCESS clinics (3 primary care, 1 sexual health, and 1 community-based HIV rapid testing service), had at least 1 follow-up visit, and were monitored until April 30, 2018. Exposures: Upon enrollment, participants received daily oral tenofovir disoproxil fumurate and emtricitabine for HIV PrEP, quarterly HIV and STI testing, and clinical monitoring. Main Outcomes and Measures: The primary outcome was incidence of chlamydia, gonorrhea, or syphilis. Incidence rates and hazard ratios describing behavioral risk factors of STI diagnosis were calculated. Incidence rate ratios (IRRs), adjusted for change in testing frequency, described changes in STI incidence from 1-year preenrollment to study follow-up among participants with preenrollment testing data (n = 1378). Results: Among the 2981 individuals (median age, 34 years [interquartile range, 28-42]), 98.5% identified as gay or bisexual males, 29% used PrEP prior to enrollment, 89 (3%) withdrew and were censored at date of withdrawal, leaving 2892 (97.0%) enrolled at final follow-up. During a mean follow-up of 1.1 years (3185.0 person-years), 2928 STIs were diagnosed among 1427 (48%) participants (1434 chlamydia, 1242 gonorrhea, 252 syphilis). STI incidence was 91.9 per 100 person-years, with 736 participants (25%) accounting for 2237 (76%) of all STIs. Among 2058 participants with complete data for multivariable analysis, younger age, greater partner number, and group sex were associated with greater STI risk, but condom use was not. Among 1378 participants with preenrollment testing data, STI incidence increased from 69.5 per 100 person-years prior to enrollment to 98.4 per 100 person-years during follow-up (IRR, 1.41 [95% CI, 1.29-1.56]). After adjusting for testing frequency, the increase in incidence from 1 year preenrollment to follow-up was significant for any STI (adjusted IRR, 1.12 [95% CI, 1.02-1.23]) and for chlamydia (adjusted IRR, 1.17 [95% CI, 1.04-1.33]). Conclusions and Relevance: Among gay and bisexual men using PrEP, STIs were highly concentrated among a subset, and receipt of PrEP after study enrollment was associated with an increased incidence of STIs compared with preenrollment. These findings highlight the importance of frequent STI testing among gay and bisexual men using PrEP.

Acceptability and HIV Prevention Benefits of a Peer-Based Model of Rapid Point of Care HIV Testing for Australian Gay, Bisexual and Other Men Who Have Sex with Men.

Frequent HIV testing among gay, bisexual and other men who have sex with men (GBM) is a strategic priority for HIV prevention in Australia. To overcome barriers to testing in conventional clinical services, Australia recently introduced peer HIV rapid point of care (RPOC) testing services for GBM. This mixed methods evaluation describes client acceptability and HIV prevention benefits of a peer HIV testing model. Most aspects of the service model were overwhelmingly acceptable to clients. Two-thirds of survey participants reported preferring testing with peers rather than doctors or nurses and over half reported learning something new about reducing HIV risk. Focus group findings suggested peer-delivered HIV RPOC testing reduced stigma-related barriers to frequent testing and provided novel opportunities for GBM to openly discuss HIV prevention and sexual practices, enhancing their HIV risk-reduction knowledge. Analysis of survey data suggested knowledge transfer occurred particularly among younger and less gay community-attached GBM.

Trial and error: evaluating and refining a community model of HIV testing in Australia.

BACKGROUND: The 2012 regulatory approval of HIV rapid point of care (RPOC) tests in Australia and a national strategic focus on HIV testing provided a catalyst for implementation of non-clinical HIV testing service models. PRONTO! opened in 2013 as a two-year trial delivering peer-led community-based HIV RPOC tests targeting gay, bisexual and other men who have sex with men (GBM), with the aim of increasing HIV testing frequency. Initial data suggested this aim was not achieved and, as part of a broader service evaluation, we sought to explore client acceptability and barriers to testing at PRONTO! to refine the service model. METHODS: We present descriptive and thematic analyses of data from two in-depth evaluation surveys and four focus groups with PRONTO! clients focused on service acceptability, client testing history, intentions to test and barriers to testing for HIV and other sexually transmitted infections (STIs). RESULTS: The three novel aspects of the PRONTO! model, testing environment, rapid-testing, peer-staff, were reported to be highly acceptable among survey and focus group participants. Focus group discussions revealed that the PRONTO! model reduced anxiety associated with HIV testing and created a comfortable environment conducive to discussing sexual risk and health. However, an absence of STI testing at PRONTO!, driven by restrictions on medical subsidies for STI testing and limited funds available at the service level created a barrier to HIV testing. An overwhelming majority of PRONTO! clients reported usually testing for STIs alongside HIV and most reported plans to seek STI testing after testing for HIV at PRONTO!. When deciding where, when and what to test for, clients reported balancing convenience and relative risk and consequences for each infection as guiding their decision-making. CONCLUSIONS: A community-based and peer-led HIV testing model reduced previously reported barriers to HIV testing, while introducing new barriers. The absence of STI testing at PRONTO! and the need to access multiple services for comprehensive sexual health screening, created a significant service engagement barrier for some clients. Understanding client motivations to access testing and ensuring novel service models meet client needs is crucial for developing acceptable sexual health services for high-risk populations.

Simulated adhesion between realistic hydrocarbon materials: effects of composition, roughness, and contact point.

The work of adhesion is an interfacial materials property that is often extracted from atomic force microscope (AFM) measurements of the pull-off force for tips in contact with flat substrates. Such measurements rely on the use of continuum contact mechanics models, which ignore the atomic structure and contain other assumptions that can be challenging to justify from experiments alone. In this work, molecular dynamics is used to examine work of adhesion values obtained from simulations that mimic such AFM experiments and to examine variables that influence the calculated work of adhesion. Ultrastrong carbon-based materials, which are relevant to high-performance AFM and nano- and micromanufacturing applications, are considered. The three tips used in the simulations were composed of amorphous carbon terminated with hydrogen (a-C-H), and ultrananocrystalline diamond with and without hydrogen (UNCD-H and UNCD, respectively). The model substrate materials used were amorphous carbon with hydrogen termination (a-C-H) and without hydrogen (a-C); ultrananocrystalline diamond with (UNCD-H) and without hydrogen (UNCD); and the (111) face of single crystal diamond with (C(111)-H) and without a monolayer of hydrogen (C(111)). The a-C-H tip was found to have the lowest work of adhesion on all substrates examined, followed by the UNCD-H and then the UNCD tips. This trend is attributable to a combination of roughness on both the tip and sample, the degree of alignment of tip and substrate atoms, and the surface termination. Continuum estimates of the pull-off forces were approximately 2-5 times larger than the MD value for all but one tip-sample pair.

Bond-order potentials with split-charge equilibration: application to C-, H-, and O-containing systems.

A method for extending charge transfer to bond-order potentials, known as the bond-order potential/split-charge equilibration (BOP/SQE) method [P. T. Mikulski, M. T. Knippenberg, and J. A. Harrison, J. Chem. Phys. 131, 241105 (2009)], is integrated into a new bond-order potential for interactions between oxygen, carbon, and hydrogen. This reactive potential utilizes the formalism of the adaptive intermolecular reactive empirical bond-order potential [S. J. Stuart, A. B. Tutein, and J. A. Harrison, J. Chem. Phys. 112, 6472 (2000)] with additional terms for oxygen and charge interactions. This implementation of the reactive potential is able to model chemical reactions where partial charges change in gas- and condensed-phase systems containing oxygen, carbon, and hydrogen. The BOP/SQE method prevents the unrestricted growth of charges, often observed in charge equilibration methods, without adding significant computational time, because it makes use of a quantity which is calculated as part of the underlying covalent portion of the potential, namely, the bond order. The implementation of this method with the qAIREBO potential is designed to provide a tool that can be used to model dynamics in a wide range of systems without significant computational cost. To demonstrate the usefulness and flexibility of this potential, heats of formation for isolated molecules, radial distribution functions of liquids, and energies of oxygenated diamond surfaces are calculated.

Relationship between Posture and Non-Contact Lower Limb Injury in Young Male Amateur Football Players: A Prospective Cohort Study.

Posture, a potentially modifiable injury risk factor, is considered important in injury screening/prevention in athletes, yet few studies investigate relationships between posture and injury. This prospective cohort study investigated whether static posture is associated with lower limb injury risk in male football players (n = 263). Nine aspects of static standing posture (left and right rearfoot, knee interspace, lateral knee, lumbar lordosis, thoracic kyphosis, scoliosis S and C, forward head) were assessed from photographs during the pre-season using the modified Watson and Mac Donncha scale, which was dichotomised for analysis (deviated or normal). Player characteristics (age, height, mass, body mass index, competition level), match/training exposure, and previous and in-season non-contact lower limb injuries were recorded. Binary logistic regression investigated relationships between posture and injury (previous and in-season). Eighty previous and 24 in-season lower limb injuries were recorded. Previous injury was not associated with any postural variable. In-season injury was associated with previous injury (OR = 3.04, 95% CI 1.20-7.68, p = 0.02) and having a normal thoracic curve compared to kyphosis (OR = 0.38, 95% CI 0.15-1.00, p = 0.05) but no other postural variables. Static postural deviations observed in male football players in the pre-season are not typically associated with non-contact lower limb injury risk; thus, they are unlikely to add value to pre-season screening programs.

Internal energy of molecules ejected due to energetic C60 bombardment.

The early stages of C(60) bombardment of octane and octatetraene crystals are modeled using molecular dynamics simulations with incident energies of 5-20 keV. Using the AIREBO potential, which allows for chemical reactions in hydrocarbon molecules, we are able to investigate how the projectile energy is partitioned into changes in potential and kinetic energy as well as how much energy flows into reacted molecules and internal energy. Several animations have been included to illustrate the bombardment process. The results show that the material near the edge of the crater can be ejected with low internal energies and that ejected molecules maintain their internal energies in the plume, in contrast to a collisional cooling mechanism previously proposed. In addition, a single C(60) bombardment was able to create many free and reacted H atoms which may aid in the ionization of molecules upon subsequent bombardment events.

Interest in Switching to On-Demand HIV Pre-Exposure Prophylaxis (PrEP) Among Australian Users of Daily PrEP: An Online Survey.

We surveyed 970 PrEPX study participants to evaluate interest in switching from daily to on-demand PrEP in a study setting. Interested respondents (n = 469, 48%) more commonly reported PrEP cessation (adjusted odds ratio [aOR], 3.0; P < .001), difficulty with adherence (aOR, 1.6; P = .029), infrequent sex (aOR, 3.7; P < .001), and toxicity concerns (aOR, 2.7; P < .001).

Assessment of service refinement and its impact on repeat HIV testing by client's access to Australia's universal healthcare system: a retrospective cohort study.

INTRODUCTION: Achieving the virtual elimination of HIV requires equitable access to HIV prevention tools for all priority populations. Restricted access to healthcare means migrants face particular barriers to HIV prevention services. In February 2016, a peer-led rapid HIV testing service for gay, bisexual and other men who have sex with men (gay and bisexual men, GBM) in Melbourne, Australia, introduced free sexually transmissible infection (STI) testing funded through Medicare (Australia's universal healthcare system). Medicare ineligible migrant clients were required to pay up to $158AUD for STI tests. We determined the uptake of STI testing and assessed the impact on repeat HIV testing among Medicare eligible and ineligible clients. METHODS: All HIV tests conducted between August 2014 and March 2018 were included. We describe client characteristics, STI testing uptake and HIV/STI positivity among Medicare eligible and ineligible clients. Repeat HIV testing, assessed as the percentage of HIV tests with a return test within six months, was compared pre-integration (August 2014-June 2016) and post-integration(July 2016-March 2018) of STI testing using segmented linear regression of monthly aggregate data for Medicare eligible and ineligible clients. RESULTS: Analyses included 9134 HIV tests among 4753 individuals. Medicare ineligible clients were younger (p < 0.01), and fewer reported previously testing for HIV (p < 0.01) and high HIV risk sexual behaviours. There was no difference in HIV positivity between the two groups (p = 0.09). STI testing uptake was significantly lower among Medicare ineligible clients (7.6%, 85.3%; p < 0.01). Following STI testing introduction there was an immediate increase in six-month return HIV testing (6.4%; p = 0.02) and a significantly increasing rate of return HIV testing between July 2016 and March 2018 (0.5% per month; p < 0.01) among Medicare eligible clients but no immediate change in return testing (-0.9%; p = 0.7) or the rate of change in return testing between July 2016 and March 2018 (0.1% per month; p = 0.3) among Medicare ineligible clients. In March 2018, six-month return HIV testing was 52.3% and 13.2% among Medicare eligible and ineligible clients respectively. DISCUSSION: Improvements in return HIV testing observed among Medicare eligible clients did not extend to Medicare ineligible clients highlighting the impact of inequitable access to comprehensive sexual healthcare on test-and-treat approaches to HIV prevention.

A comparative, retrospective analysis of HIV testing among gay, bisexual and other men who have sex with men in Melbourne, Australia.

OBJECTIVE: PRONTO!, a peer-led rapid HIV-testing service in Melbourne, Australia, opened to improve HIV testing among gay and bisexual men (GBM). We compared client characteristics and return testing among GBM testing at PRONTO! with GBM testing at Melbourne Sexual Health Centre (MSHC). METHODS: All GBM attending PRONTO! and MSHC for HIV testing between August 2013 and April 2016 were included. We describe the number of tests, percentage of clients who returned during follow-up, the mean number of tests and median time between tests at the two services. RESULTS: At PRONTO!, 33% of 3,102 GBM and at MSHC 50% of 9,836 GBM returned for a further HIV test at least once. The mean number of tests per client was 1.7 and 2.5 at PRONTO! and MSHC (p<0.01), respectively. A majority of clients at both services reported behaviours that would recommend up to quarterly testing, however, the median time between tests was 20.0 and 17.0 weeks at PRONTO! and MSHC (p<0.01), respectively. CONCLUSIONS: A greater proportion of clients returned and returned frequently at MSHC compared to PRONTO!, however, at both services HIV testing frequency was suboptimal. Implications for public health: Novel HIV testing services should provide convenient and comprehensive sexual health services.

Energy deposition control during cluster bombardment: a molecular dynamics view.

Molecular dynamics simulations are performed to model C60 and Au3 bombardment of a molecular solid, benzene, in order to understand the energy deposition placement as a function of incident kinetic energy and incident angle. Full simulations are performed for 5 keV projectiles, and the yields are calculated. For higher energies, 20 and 40 keV, the mesoscale energy deposition footprint model is employed to predict trends in yield. The damage accumulation is discussed in relationship to the region where energy is deposited to the sample. The simulations show that the most favorable conditions for increasing the ejection yield and decreasing the damage accumulation are when most of the projectile energy is deposited in the near-surface region. For molecular organic solids, grazing angles are the best choice for achieving these conditions.

Cluster size dependence and yield linearity in cluster bombardment simulations of benzene.

Cluster bombardment of a molecular solid, benzene, is modeled using molecular dynamics simulations in order to investigate the effect of projectile cluster size and incident energy on the resulting yield. Using the mesoscale energy deposition footprint (MEDF) model, we are able to model large projectiles with incident energies from 5 to 140 keV and predict trends in ejection yield. The highest ejection yield at 5 keV was observed at C 20 and C 60, but shifts toward larger clusters for higher energies. These trends are explained in terms of the MEDF model. For these projectiles, all of the incident energy is deposited in the near-surface region, which is optimal for the projectile energy to contribute to the ejection yield. Because the energy is deposited in the optimal position for contributing to the ejection process, the yields increase linearly with incident energy with a slope that is nearly independent of the cluster size.

Implications of survey labels and categorisations for understanding drug use in the context of sex among gay and bisexual men in Melbourne, Australia.

BACKGROUND: Reliably measuring drug use by gay, bisexual and other men who have sex with men (GBM) in the context of sex can inform sexual health service responses. We report changing drug use patterns among GBM testing for HIV at a community-based service in Melbourne in response to behavioural survey modifications. METHODS: Surveys were completed by GBM prior to all HIV tests. Survey one asked about use of "party drugs for the purpose of sex" and survey two asked about specific drug use (alcohol, amyl nitrate, methamphetamine, cocaine, ecstasy, GHB, Viagra®/Cialis®) before or during sex. Differences in drug use prevalence and demographic and sexual risk correlates are reported. RESULTS: Reported drug use increased from 16.9% in survey one to 54.0% in survey two. Among GBM completing both surveys, 45% who reported no drug use in survey one reported drug use in survey two. Drug use was associated with high HIV risk behaviours across both surveys. CONCLUSION: Survey modification improved ascertainment of drug use in the context of sex among GBM. Continued monitoring of drug use in this setting will improve our understanding the relationship between use of specific drugs and sexual health and help inform client focused health promotion.

Protocol for an HIV Pre-exposure Prophylaxis (PrEP) Population Level Intervention Study in Victoria Australia: The PrEPX Study.

Background: Pre-exposure prophylaxis (PrEP) is the use of HIV anti-retroviral therapy to prevent HIV transmission in people at high risk of HIV acquisition. PrEP is highly efficacious when taken either daily, or in an on-demand schedule. In Australia co-formulated tenofovir-emtricitabine is registered for daily use for PrEP, however, this co-formulation is not listed yet on the national subsidized medicines list. We describe a study protocol that aims to demonstrate if the provision of PrEP to up to 3800 individuals at risk of HIV in Victoria, Australia reduces HIV incidence locally by 25% generally and 30% among GBM. Methods: PrEPX is a population level intervention study in Victoria, Australia in which generic PrEP will be delivered to 3800 individuals for up to 36 months. Study eligibility is consistent with the recently updated 2017 Australian PrEP guidelines. Participants will attend study clinics, shared care clinics, or outreach clinics for quarterly HIV/STI screening, biannual renal function tests and other clinical care as required. Study visits and STI diagnoses will be recorded electronically through the ACCESS surveillance system. At each study visit participants will be invited to complete behavioral surveys that collect demographics and sexual risk data. Diagnosis and behavioral data will be compared between PrEPX participants and other individuals testing within the ACCESS surveillance system. A subset of participants will complete in depth surveys and interviews to collect attitudes, beliefs and acceptability data. Participating clinics will provide clinic level data on implementation and management of PrEPX participants. The population level impact on HIV incidence will be assessed using Victorian HIV notification data. Discussion: This study will collect evidence on the real world impact of delivery of PrEP to 3800 individuals at risk of acquiring HIV in Victoria. This study will provide important information for the broader implementation of PrEP planning upon listing of the tenofovir-emtricitabine on the national subsidized list of medicines. The study is registered on the Australian New Zealand Clinical Trials Registry (ACTRN12616001215415).

Characteristics of gay, bisexual and other men who have sex with men testing and retesting at Australia's first shop-front rapid point-of-care HIV testing service.

BACKGROUND: HIV rapid point-of-care (RPOC) testing was approved in Australia in 2012 prompting new testing models. We describe gay, bisexual and other men who have sex with men (GBM) testing in the first year of operations at Australia's first shop-front, community-based RPOC testing service, PRONTO!, and characterise return testers and first-time testers. METHODS: Univariable and multivariable logistic regression using data collected at clients' first test at PRONTO! from 15 August 2013 to 14 August 2014 examined correlates of: 1) return-testing within 6 months of GBMs first test at PRONTO!; and 2) reporting a first ever HIV test at PRONTO!. RESULTS: In the first year, 1226 GBM tested at PRONTO! (median age=30.4 years, 60.2% Australian born). Condomless anal sex with casual or regular partners was reported by 45% and 66% of GBM, respectively. Almost one-quarter (23%) of GBM returned within 6 months of their first test. Return-testing was associated with being born overseas (adjusted odds ratio (AOR)=1.48, 95% confidence interval (CI)=1.10-2.0), reporting a regular check-up as reason to test (AOR=1.53, 95% CI=1.01-2.30) and reporting a HIV test in the 6 months before first testing at PRONTO! (AOR=1.73, 95% CI=1.09-2.73). Reporting first testing at PRONTO! (17.9%) was positively associated with younger age (<30 years; AOR=1.78, 95% CI=1.18-2.71) and negatively associated with reporting a regular check-up as reason to test (AOR=0.45, 95% CI=0.29-0.71) and recent group sex (AOR=0.37, 95% CI=0.23-0.59). CONCLUSION: Despite PRONTO! being designed to reduce barriers to HIV testing, return testing rates in the first year were low and not associated with client risk. Service refinements, including the provision of comprehensive sexually transmissible infection testing, are needed to increase testing frequency and enhance population HIV prevention benefits.