The Impact of Preexposure Prophylaxis Among Men Who Have Sex With Men: An Individual-Based Model

Agent based modelling of blood borne viruses: a scoping review

BACKGROUND

The models that historically have been used to model infectious disease outbreaks are equation-based and statistical models. However, these models do not capture the impact of individual and social factors that affect the spread of common blood-borne viruses (BBVs) such as human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV). Agent-based modelling (ABM) is an alternative modelling approach that is gaining popularity in public health and epidemiology. As the field expands, it is important to understand how ABMs have been applied. In this context, we completed a scoping review of research that has been done on the ABM of BBVs.

METHOD

The inclusion/exclusion criteria were drafted using the idea of Population, Concept, and Context (PCC). The Preferred Reporting Item for Systematic Reviews and Meta-Analysis, an extension to scoping review (PRISMA-ScR), was employed in retrieving ABM literature that studied BBVs. Three databases (Scopus, Pubmed, and Embase) were systematically searched for article retrieval. 200 articles were retrieved from all the databases, with 10 duplicates. After removing the duplicates, 190 papers were screened for inclusion. After analysing the remaining articles, 70 were excluded during the abstract screening phase, and 32 were excluded during the full-text decision. Eighty-eight were retained for the scoping review analysis. To analyse this corpus of 88 papers, we developed a five-level taxonomy that categorised each paper based first on disease type, then transmission mechanism, then modelled population, then geographic location and finally, model outcome.

RESULTS

The result of this analysis show significant gaps in the ABM of BBV literature, particularly in the modeling of social and individual factors influencing BBV transmission.

CONCLUSION

There is a need for more comprehensive models that address various outcomes across different populations, transmission and intervention mechanisms. Although ABMs are a valuable tool for studying BBVs, further research is needed to address existing gaps and improve our understanding of individual and social factors that influence the spread and control of BBVs. This research can inform researchers, modellers, epidemiologists, and public health practitioners of the ABM research areas that need to be explored to reduce the burden of BBVs globally.

Oral HIV pre-exposure prophylaxis use and resistance-associated mutations among men who have sex with men and transgender persons newly diagnosed with HIV in the Netherlands: results from the ATHENA cohort, 2018 to 2022

BackgroundIn the Netherlands, HIV pre-exposure prophylaxis (PrEP) has been available since 2019. However, the extent of PrEP use prior to HIV diagnosis and development of PrEP-resistance-associated mutations (RAMs) is not known.AimWe assessed prior PrEP use and potential transmission of PrEP RAMs among men who have sex with men (MSM) and transgender persons (TGP) with a new HIV diagnosis in the Netherlands.MethodsData on prior PrEP use between 1 January 2018 and 31 December 2022 were available from the Dutch national ATHENA cohort. We assessed proportion of prior PrEP use, detected PrEP associated RAMs and assessed potential onward transmission of RAMs between 2010 and 2022 using a maximum likelihood tree.ResultsData on prior PrEP use were available for 583/1,552 (36.3%) individuals, with 16% (94/583) reporting prior PrEP use. In 489 individuals reporting no prior PrEP use, 51.5% did not use PrEP due to: low HIV-risk perception (29%), no access (19.1%), personal preference (13.1%), and being unaware of PrEP (19.1%). For PrEP users, 13/94 (13.8%) harboured a M184V/I mutation, of whom two also harboured a K65R mutation. In people with a recent HIV infection, detection of PrEP RAMs increased from 0.23% (2/862) before 2019 to 4.11% (9/219) from 2019. We found no evidence of onward transmission of PrEP RAMs.ConclusionThe prevalence of PrEP-associated RAMs has increased since PrEP became available in the Netherlands. More widespread access to PrEP and retaining people in PrEP programmes when still at substantial risk is crucial to preventing new HIV infections.

Understanding effective post-test linkage strategies for HIV prevention and care: a scoping review

INTRODUCTION

Following HIV testing services (HTS), the World Health Organization recommends prompt linkage to prevention and treatment. Scale-up of effective linkage strategies is essential to achieving the global 95-95-95 goals for maintaining low HIV incidence by 2030 and reducing HIV-related morbidity and mortality. Whereas linkage to care including same-day antiretroviral therapy (ART) initiation for all people with HIV is now routinely implemented in testing programmes, linkage to HIV prevention interventions including behavioural or biomedical strategies, for HIV-negative individuals remains sub-optimal. This review aims to evaluate effective post-HTS linkage strategies for HIV overall, and highlight gaps specifically in linkage to prevention.

METHODS

Using the five-step Arksey and O'Malley framework, we conducted a scoping review searching existing published and grey literature. We searched PubMed, Cochrane Library, CINAHL, Web of Science and EMBASE databases for English-language studies published between 1 January 2010 and 30 November 2023. Linkage interventions included as streamlined interventions-involving same-day HIV testing, ART initiation and point-of-care CD4 cell count/viral load, case management-involving linkage coordinators developing personalized HIV care and risk reduction plans, incentives-financial and non-financial, partner services-including contact tracing, virtual-like social media, quality improvement-like use of score cards, and peer-based interventions. Outcomes of interest were linkage to any form of HIV prevention and/or care including ART initiation.

RESULTS

Of 2358 articles screened, 66 research studies met the inclusion criteria. Only nine linkage to prevention studies were identified (n = 9/66, 14%)-involving pre-exposure prophylaxis, voluntary medical male circumcision, sexually transmitted infection and cervical cancer screening. Linkage to care studies (n = 57/66, 86%) focused on streamlined interventions in the general population and on case management among key populations.

DISCUSSION

Despite a wide range of HIV prevention interventions available, there was a dearth of literature on HIV prevention programmes and on the use of messaging on treatment as prevention strategy. Linkage to care studies were comparatively numerous except those evaluating virtual interventions, incentives and quality improvement.

CONCLUSIONS

The findings give insights into linkage strategies but more understanding of how to provide these effectively for maximum prevention impact is needed.

Causal Effects of Stochastic PrEP Interventions on HIV Incidence Among Men Who Have Sex With Men

Antiretroviral preexposure prophylaxis (PrEP) is highly effective in preventing human immunodeficiency virus (HIV) infection, but uptake has been limited and inequitable. Although interventions to increase PrEP uptake are being evaluated in clinical trials among men who have sex with men (MSM), those trials cannot evaluate effects on HIV incidence. Estimates from observational studies of the causal effects of PrEP-uptake interventions on HIV incidence can inform decisions about intervention scale-up. We used longitudinal electronic health record data from HIV-negative MSM accessing care at Fenway Health, a community health center in Boston, Massachusetts, from January 2012 through February 2018, with 2 years of follow-up. We considered stochastic interventions that increased the chance of initiating PrEP in several high-priority subgroups. We estimated the effects of these interventions on population-level HIV incidence using a novel inverse-probability weighted estimator of the generalized g-formula, adjusting for baseline and time-varying confounders. Our results suggest that even modest increases in PrEP initiation in high-priority subgroups of MSM could meaningfully reduce HIV incidence in the overall population of MSM. Interventions tailored to Black and Latino MSM should be prioritized to maximize equity and impact.

Population-level effectiveness of pre-exposure prophylaxis for HIV prevention among men who have sex with men in Montréal (Canada): a modelling study of surveillance and survey data

INTRODUCTION

HIV pre-exposure prophylaxis (PrEP) has been recommended and partly subsidized in Québec, Canada, since 2013. We evaluated the population-level impact of PrEP on HIV transmission among men who have sex with men (MSM) in Montréal, Québec's largest city, over 2013-2021.

METHODS

We used an agent-based mathematical model of sexual HIV transmission to estimate the fraction of HIV acquisitions averted by PrEP compared to a counterfactual scenario without PrEP. The model was calibrated to local MSM survey, surveillance, and cohort data and accounted for COVID-19 pandemic impacts on sexual activity, HIV prevention, and care. PrEP was modelled from 2013 onwards, assuming 86% individual-level effectiveness. The PrEP eligibility criteria were: any anal sex unprotected by condoms (past 6 months) and either multiple partnerships (past 6 months) or multiple uses of post-exposure prophylaxis (lifetime). To assess potential optimization strategies, we modelled hypothetical scenarios prioritizing PrEP to MSM with high sexual activity (≥11 anal sex partners annually) or aged ⩽45 years, increasing coverage to levels achieved in Vancouver, Canada (where PrEP is free-of-charge), and improving retention.

RESULTS

Over 2013-2021, the estimated annual HIV incidence decreased from 0.4 (90% credible interval [CrI]: 0.3-0.6) to 0.2 (90% CrI: 0.1-0.2) per 100 person-years. PrEP coverage among HIV-negative MSM remained low until 2015 (<1%). Afterwards, coverage increased to a maximum of 10% of all HIV-negative MSM, or about 16% of the 62% PrEP-eligible HIV-negative MSM in 2020. Over 2015-2021, PrEP averted an estimated 20% (90% CrI: 11%-30%) of cumulative HIV acquisitions. The hypothetical scenarios modelled showed that, at the same coverage level, prioritizing PrEP to high sexual activity MSM could have averted 30% (90% CrI: 19%-42%) of HIV acquisitions from 2015-2021. Even larger impacts could have resulted from higher coverage. Under the provincial eligibility criteria, reaching 10% coverage among HIV-negative MSM in 2015 and 30% in 2019, like attained in Vancouver, could have averted up to 63% (90% CrI: 54%-70%) of HIV acquisitions from 2015 to 2021.

CONCLUSIONS

PrEP reduced population-level HIV transmission among Montréal MSM. However, our study suggests missed prevention opportunities and adds support for public policies that reduce PrEP barriers, financial or otherwise, to MSM at risk of HIV acquisition.

Modeling the Impact of HIV-1 Nucleic Acid Testing Among Symptomatic Adult Outpatients in Kenya

BACKGROUND

Up to 69% of adults who acquire HIV in Kenya seek care before seroconversion, providing an important opportunity for early diagnosis and treatment. The Tambua Mapema Plus (TMP) trial tested a combined HIV-1 nucleic acid testing, linkage, treatment, and partner notification intervention for adults aged 18-39 years with symptoms of acute HIV infection presenting to health facilities in coastal Kenya. We estimated the potential impact of TMP on the Kenyan HIV epidemic.

METHODS

We developed an agent-based network model of HIV-1 transmission using TMP data and Kenyan statistics to estimate potential population-level impact of targeted facility-based testing over 10 years. Three scenarios were modeled: standard care [current use of provider-initiated testing and counseling (PITC)], standard HIV rapid testing scaled to higher coverage obtained in TMP (scaled-up PITC), and the TMP intervention.

RESULTS

Standard care resulted in 90.7% of persons living with HIV (PLWH) knowing their status, with 67.5% of those diagnosed on treatment. Scaled-up PITC resulted in 94.4% of PLWH knowing their status and 70.4% of those diagnosed on treatment. The TMP intervention achieved 97.5% of PLWH knowing their status and 80.6% of those diagnosed on treatment. The percentage of infections averted was 1.0% (95% simulation intervals: -19.2% to 19.9%) for scaled-up PITC and 9.4% (95% simulation intervals: -8.1% to 24.5%) for TMP.

CONCLUSION

Our study suggests that leveraging new technologies to identify acute HIV infection among symptomatic outpatients is superior to scaled-up PITC in this population, resulting in >95% knowledge of HIV status, and would reduce new HIV infections in Kenya.

Are Unequal Policies in Pre-Exposure Prophylaxis Uptake Needed to Improve Equality? An Examination Among Men Who Have Sex with Men in Los Angeles County

Racial and ethnic minority men who have sex with men (MSM) are disproportionately affected by HIV/AIDS in Los Angeles County (LAC), an important epicenter in the battle to end HIV. We examine tradeoffs between effectiveness and equality of pre-exposure prophylaxis (PrEP) allocation strategies among different racial and ethnic groups of MSM in LAC and provide a framework for quantitatively evaluating disparities in HIV outcomes. To do this, we developed a microsimulation model of HIV among MSM in LAC using county epidemic surveillance and survey data to capture demographic trends and subgroup-specific partnership patterns, disease progression, patterns of PrEP use, and patterns for viral suppression. We limit analysis to MSM, who bear most of the burden of HIV/AIDS in LAC. We simulated interventions where 3000, 6000, or 9000 PrEP prescriptions are provided annually in addition to current levels, following different allocation scenarios to each racial/ethnic group (Black, Hispanic, or White). We estimated cumulative infections averted and measures of equality, after 15 years (2021-2035), relative to base case (no intervention). By comparing allocation strategies on the health equality impact plane, we find that, of the policies evaluated, targeting PrEP preferentially to Black individuals would result in the largest reductions in incidence and disparities across the equality measures we considered. This result was consistent over a range of PrEP coverage levels, demonstrating that there are "win-win" PrEP allocation strategies that do not require a tradeoff between equality and efficiency.

Cost-Effectiveness of Interventions to Improve HIV Pre-exposure Prophylaxis Initiation, Adherence, and Persistence Among Men Who Have Sex With Men

BACKGROUND

To help achieve Ending the HIV Epidemic (EHE) goals of reducing new HIV incidence, pre-exposure prophylaxis (PrEP) use and engagement must increase despite multidimensional barriers to scale-up and limitations in funding. We investigated the cost-effectiveness of interventions spanning the PrEP continuum of care.

SETTING

Men who have sex with men in Atlanta, GA, a focal jurisdiction for the EHE plan.

METHODS

Using a network-based HIV transmission model, we simulated lifetime costs, quality-adjusted life years (QALYs), and infections averted for 8 intervention strategies using a health sector perspective. Strategies included a status quo (no interventions), 3 distinct interventions (targeting PrEP initiation, adherence, or persistence), and all possible intervention combinations. Cost-effectiveness was evaluated incrementally using a $100,000/QALY gained threshold. We performed sensitivity analyses on PrEP costs, intervention costs, and intervention coverage.

RESULTS

Strategies averted 0.2%-4.2% new infections and gained 0.0045%-0.24% QALYs compared with the status quo. Initiation strategies achieved 20%-23% PrEP coverage (up from 15% with no interventions) and moderate clinical benefits at a high cost, while adherence strategies were relatively low cost and low benefit. Under our assumptions, the adherence and initiation combination strategy was cost-effective ($86,927/QALY gained). Sensitivity analyses showed no strategies were cost-effective when intervention costs increased by 60% and the strategy combining all 3 interventions was cost-effective when PrEP costs decreased to $1000/month.

CONCLUSION

PrEP initiation interventions achieved moderate public health gains and could be cost-effective. However, substantial financial resources would be needed to improve the PrEP care continuum toward meeting EHE goals.

HIV pre-exposure prophylaxis and sexually transmitted infections: intersection and opportunity

Pre-exposure prophylaxis (PrEP) has revolutionized HIV prevention, but PrEP does not protect against other sexually transmitted infections (STIs). Rates of STIs are rising worldwide, with notably high incidences among PrEP-using men who have sex with men in high-income countries; in low-income and middle-income countries, data are sparse, but results from a limited number of studies among African women initiating and taking PrEP have shown high STI prevalence and incidence. Efforts aimed at markedly reducing HIV in populations worldwide include a major focus on increasing PrEP use, along with improving HIV testing and treatment in order to eliminate HIV transmission. Together, these efforts could augment continued expansion of the global STI epidemic, but they could alternatively create an opportunity to improve STI control, including the development of comprehensive sexual health programmes and research to develop new STI prevention strategies. The introduction of PrEP globally has been characterized by challenges and many successes, and its role as part of a range of robust strategies to reduce HIV infections is clear. Looking ahead, understanding rising rates of curable STIs and their relationship to HIV prevention, and considering the future directions for synergies in PrEP and STI prevention will be integral to improving sexual health.

PrEP Disclosure Experiences of Gay and Bisexual Men in Guatemala

Pre-exposure prophylaxis (PrEP) can reduce HIV transmission among gay and bisexual men (GBM). However, stigma can inhibit disclosure of PrEP use, which may limit uptake. This study's purpose was to explore PrEP disclosure experiences and how disclosure is associated with PrEP adherence among GBM at a sexual health clinic in Guatemala City. We conducted in-depth interviews with PrEP users (n = 18) and used an iterative content analysis approach. All participants had or planned to disclose their PrEP use to at least one person, most commonly friends and sex partners, though many were selective about who they told. Main reasons for disclosure were to educate others, gain social support, and clarify their HIV status. Concerns about stigma and emotional discomfort deterred disclosure. Disclosure facilitated PrEP access and adherence by enhancing emotional and instrumental support. Interventions providing opportunities for GBM to practice disclosure, including addressing others' misconceptions, could promote PrEP uptake and adherence.

Reaching Those Most at Risk for HIV Acquisition: Evaluating Racial/Ethnic Disparities in the Preexposure Prophylaxis Care Continuum in Baltimore City, Maryland

BACKGROUND

Reducing HIV incidence requires addressing persistent racial/ethnic disparities in HIV burden. Our goal was to evaluate preexposure prophylaxis (PrEP) delivery, overall and relative to community need, among 7 clinical sites participating in a health department-led demonstration project to increase PrEP in Baltimore city, MD.

METHODS

PrEP care continuum stages (screened, indicated, referred, linked, evaluated, prescribed) were examined among HIV-negative individuals receiving services at participating sites between September 30, 2015 and September 29, 2019. Community need was defined using information on new HIV diagnoses (2016-2018). Differences in care continuum progression by demographics/priority population and comparison of demographic compositions between care continuum stages and new HIV diagnoses were examined using modified Poisson regression and χ2 tests, respectively.

RESULTS

Among 25,886 PrEP-screened individuals, the majority were non-Hispanic (NH) black (81.1%, n = 20,998), cisgender male (61.1%, n = 15,825), and heterosexual (86.7%, n = 22,452). Overall, 31.1% (n = 8063) were PrEP-indicated; among whom, 56.8% (n = 4578), 15.6% (n = 1250), 10.8% (n = 868), and 9.0% (n = 722) were PrEP-referred, linked, evaluated, and prescribed, respectively. Among 2870 men who have sex with men (MSM), 18.7% (n = 538) were PrEP-prescribed. Across all groups, the highest attrition was between PrEP-referred and PrEP-linked. NH-black race (vs. NH-white) was independently associated with lower likelihood of PrEP prescription (aPR, 0.89; 95% confidence interval, 0.81 to 0.98 controlling for age/gender). Relative to the demographic composition of new HIV diagnoses, fewer NH-blacks (80.2% vs. 54.3%) and more NH-whites (10.7% vs. 30.3%) and MSM were PrEP prescribed (55.2% vs. 74.5%).

CONCLUSIONS

This project showed promise delivering PrEP referrals and prescriptions overall and to MSM. Substantial improvement is needed to improve linkage overall and to decrease disparities in PrEP prescriptions among NH-blacks. Future work should focus on addressing service gaps that hinder PrEP utilization.

Comparison of two simulators for individual based models in HIV epidemiology in a population with HSV 2 in Yaoundé (Cameroon)

Model comparisons have been widely used to guide intervention strategies to control infectious diseases. Agreement between different models is crucial for providing robust evidence for policy-makers because differences in model properties can influence their predictions. In this study, we compared models implemented by two individual-based model simulators for HIV epidemiology in a heterosexual population with Herpes simplex virus type-2 (HSV-2). For each model simulator, we constructed four models, starting from a simplified basic model and stepwise including more model complexity. For the resulting eight models, the predictions of the impact of behavioural interventions on the HIV epidemic in Yaoundé-Cameroon were compared. The results show that differences in model assumptions and model complexity can influence the size of the predicted impact of the intervention, as well as the predicted qualitative behaviour of the HIV epidemic after the intervention. These differences in predictions of an intervention were also observed for two models that agreed in their predictions of the HIV epidemic in the absence of that intervention. Without additional data, it is impossible to determine which of these two models is the most reliable. These findings highlight the importance of making more data available for the calibration and validation of epidemiological models.

Pre-Exposure Prophylaxis Care Continuum, Barriers, and Facilitators among Black Men Who Have Sex with Men in the United States: A Systematic Review and Meta-Analysis

Pre-exposure prophylaxis (PrEP) represents a viable HIV prevention tool for black men who have sex with men (BMSM). However, aggregated evidence regarding the presentations and determinants of the PrEP continuum (e.g., awareness, willingness, intention, uptake and adherence) remains absent to empirically inform future intervention efforts. We meta-analytically summarized the prevalence and qualitatively synthesized key barriers/facilitators of the stages of the PrEP continuum among a pooled sample of 42,870 BMSM aggregated from 56 published studies. Our random-effect models indicated a pooled prevalence of PrEP awareness (50.8%, 95% CI: 43.6-58.0%, willingness/intention (58.2%, 95% CI: 52.0-68.1%) and uptake (15.5%, 95% CI: 12.8-18.2%). Qualitative summary revealed that perception of HIV risk, intersectional/PrEP-related stigma and medical mistrust were among the most quoted factors that influence PrEP use. BMSM remain underrepresented in key stages of the PrEP continuum. Futures interventions are continuously needed to target multilevel barriers/facilitators to enhance the PrEP continuum among BMSM.

Qualitative assessment of readiness for use of HIV pre-exposure prophylaxis among men who have sex with men (MSM) in Malawi: Qualitative study using key informant interviews and focus group discussions

Background

Men who have sex with men (MSM) are a key group for HIV interventions in Malawi considering their high HIV prevalence (17.5% compared to 8.4% among men in the general population). The use of oral preexposure prophylaxis (PrEP) presents a new opportunity for MSM to be protected. We present the findings from a qualitative assessment designed to assess awareness of and willingness and barriers to using PrEP among MSM in Malawi.

Objective

The 3 main objectives of this assessment were to determine: (1) awareness of PrEP, (2) factors that influence willingness to use PrEP, and (3) potential barriers to PrEP use and adherence among MSM in order to guide the design and implementation of a PrEP program in Malawi.

Methods

Ahead of the introduction of PrEP in Malawi, a qualitative study using in-depth interviews (IDIs) and focus group discussions (FGDs) was conducted in October 2018 in Blantyre, Lilongwe, and rural districts of Mzimba North and Mangochi. With support of members of the population, study participants were purposively recruited from 4 MSM-friendly drop-in centers where MSM receive a range of health services to ensure representativeness across sites and age. Participants were asked what they had heard about PrEP, their willingness to use PrEP, their barriers to PrEP use, and their preferences for service delivery. The data were analyzed using a thematic content analysis framework that was predetermined in line with objectives.

Results

A total of 109 MSM were interviewed—13 through IDIs and 96 through FGDs. Most participants were aware of PrEP as a new HIV intervention but had limited knowledge related to its use. However, the majority were willing to use it and were looking forward to having access to it. IDI participants indicated that they will be more willing to take PrEP if the dosing frequency were appropriate and MSM were involved in information giving and distribution of the drug. FGD participants emphasized that places of distribution and characteristics of the service provider are the key factors that will affect use. Knowing the benefits of PrEP emerged as a key theme in both the IDIs and FGDs. Participants highlighted barriers that would hinder them from taking PrEP such as side effects which were cited in IDIs and FGDs. Key factors from FGDs include cost, fear of being outed, drug stockouts, fear of being known as MSMs by wives, and lack of relevant information. FGDs cited stigma from health care workers, forgetfulness, and community associated factors.

Conclusions

Despite having inadequate knowledge about PrEP, study participants were largely willing to use PrEP if available. Programs should include an effective information, education, and communication component around their preferences and provide PrEP in MSM-friendly sites.

Patterns of PrEP Retention Among HIV Pre-exposure Prophylaxis Users in Baltimore City, Maryland

BACKGROUND

HIV pre-exposure prophylaxis (PrEP) retention, defined as quarterly clinical evaluation, is critical to reducing HIV incidence. Our objectives were to determine: (1) visit- and individual-level PrEP retention patterns; (2) and individual-level characteristics associated with low-level PrEP retention 12 months after initiation among PrEP users in Baltimore City, Maryland.

METHODS

Information was abstracted from medical records among individuals initiating PrEP between October 1, 2015 and February 28, 2018. Visit-level PrEP retention was defined as evidence of PrEP use, documented PrEP prescription, or current PrEP use at each quarterly follow-up visit. Low-level PrEP retention was defined as <3/4 quarters with documented PrEP use. Multilevel mixed effects Poisson regression was used to determine characteristics associated with low-level PrEP retention.

RESULTS

Among 412 individuals initiating PrEP and followed for 12 months, the majority was: cis-gender male (83.7%, n = 345), non-Hispanic Black (56.3%, n = 232) and gay, bisexual, or other man who has sex with men (74.0%, n = 305). By quarterly visits, PrEP retention was: 3-month: 69.4% (n = 286); 6-month: 51.9% (n = 214); 9-month: 44.5% (n = 183); and 12-month: 41.1% (n = 169). Three-fifths (58.5%, n = 241) had low-level PrEP retention. Cis-gender females (vs. cis-gender males) (adjusted relative risk: 1.36, 95% confidence interval: 1.04 to 1.77) were more likely to have low-level PrEP retention.

CONCLUSIONS

Our observed PrEP retention rates are lower than what may be needed to reduce HIV incidence. Future research should examine individual- and clinic-level barriers and facilitators to PrEP retention programs by key population to inform interventions for PrEP retention.

Population-level effectiveness of a national HIV preexposure prophylaxis programme in MSM

OBJECTIVE

The aim of this study was to evaluate Scotland's national HIV preexposure prophylaxis (PrEP) programme in relation to PrEP uptake and associated population-level impact on HIV incidence among MSM.

DESIGN

A retrospective cohort study within real-world implementation.

METHODS

Comparison of HIV diagnoses from national surveillance data and HIV incidence within a retrospective cohort of HIV-negative MSM attending sexual health clinics from the National Sexual Health information system between the 2-year periods pre(July 2015-June 2017) and post(July 2017-June 2019) introduction of PrEP.

RESULTS

Of 16 723 MSM attending sexual health services in the PrEP period, 3256 (19.5%) were prescribed PrEP. Between pre-PrEP and PrEP periods, new HIV diagnoses among MSM declined from 229 to 184, respectively [relative risk reduction (RRR): 19.7%, 95% confidence interval (95% CI) 2.5-33.8]; diagnosed recently acquired infections declined from an estimated 73 to 47, respectively (35.6%, 95% CI 7.1-55.4). Among MSM attending sexual health clinics, HIV incidence per 1000 person-years declined from 5.13 (95% CI 3.90-6.64) pre-PrEP to 3.25 (95% CI 2.30-4.47) in the PrEP period (adjusted IRR 0.57, 95% CI 0.37-0.87). Compared with the pre-PrEP period, incidence of HIV was lower in the PrEP period for those prescribed PrEP (aIRR 0.25, 95% CI 0.09-0.70) and for those not prescribed PrEP (aIRR 0.68, 95% CI 0.43-1.05).

CONCLUSION

We demonstrate national population-level impact of PrEP for the first time in a real-world setting. HIV incidence reduced in MSM who had been prescribed PrEP and, to a lesser extent, in those who had not. Promotion of the benefits of PrEP needs to extend to MSM who do not access sexual health clinics.

Preference for using a variety of future HIV pre-exposure prophylaxis products among men who have sex with men in three US cities

BACKGROUND

Daily oral pre-exposure prophylaxis (PrEP) is available and recommended for men who have sex with men (MSM) at risk for HIV infection. Other HIV prevention products are being developed, including long-acting injectable (LAI) and event-based oral and topical formulations. Understanding preferences for potential products by MSM can help direct further development of prevention messaging.

METHODS

We present baseline data from HIV-negative participants enrolled in the US Mobile Messaging for Men (M-cubed) Study. Participants were asked their likelihood of and rank order preference for using daily oral PrEP and various potential prevention products (one- to -three-month injections, 2-1-1 sexual event oral dosing, anal or penile gel, or anal suppository), and their sociodemographic characteristics. Bivariate and multivariable logistics regression assessed demographic associations with likelihood of use and rank order preference.

RESULTS

Overall, most MSM reported a likelihood of using LAI (74%), sexual event-based pills (67%) and penile gel (64%). Men who reported recent unprotected (condomless and PrEPless) anal sex most preferred a penile gel formulation (74%), followed closely by LAI and event-based pills (73% each). Current PrEP users (vs. non-users) had greater odds of reporting likelihood to use LAI (AOR = 3.29, 95% CI = 2.12 to 5.11), whereas men reporting recent unprotected anal sex had a greater odds of likelihood to use a penile gel (AOR = 1.79, 95% CI = 1.27 to 2.52) and an anal suppository (AOR = 1.48, 95% CI = 1.08 to 2.02). Hispanic/Latino (vs. White) MSM (AOR = 2.29, 95% CI = 1.40 to 3.73) and, marginally, Black MSM (AOR = 1.54, 95% CI = 1.00 to 2.38) had greater odds of reporting likelihood to use penile gel. Similar patterns were found for rank ordering preference of products, including condoms.

CONCLUSIONS

Most MSM were interested in using various potential future HIV prevention products, especially LAI. However, two typologies of potential users emerged: men who prefer sexual event-based methods (condoms, event-based pill, sexual gels and suppositories) and men who prefer non-sexual event-based methods (daily pill, LAI). Men who reported recent unprotected anal sex preferred a penile gel product most, followed closely by sexual event-based pills and LAI. Racial/ethnic differences were noted as well. These findings on product preferences can help in formulation development and messaging.

Combination HIV Prevention Strategies Among Montreal Gay, Bisexual, and Other Men Who Have Sex with Men in the PrEP Era: A Latent Class Analysis

Pre-exposure prophylaxis (PrEP) became publicly available in Quebec for gay, bisexual and other men who have sex with men (GBM) in 2013. We used baseline data from Engage, a cohort of GBM recruited by respondent-driven sampling, to examine patterns of combination HIV prevention use among Montreal GBM since PrEP became available. Latent class analysis, stratified by HIV status, was used to categorize GBM by self-reported use of biomedical and behavioural prevention strategies. Correlates of resulting classes were identified using multinomial logistic regression. Among HIV-negative/unknown GBM (n = 968), we identified four classes: low use of prevention (32%), condoms (40%), seroadaptive behaviour (21%), and biomedical (including PrEP; 7%). Those using prevention (condoms, seroadaptive behaviour, and biomedical) had a higher number of anal sex partners and were more likely to report a recent sexually transmitted infection diagnosis. GBM using biomedical prevention also had a higher level of formal education. Among GBM living with HIV (n = 200), we identified three classes: mainly antiretroviral treatment (ART) with viral suppression (53%), ART with viral suppression and condoms (19%), and ART with viral suppression and seroadaptive behaviour (18%). Again, the number of anal sex partners was higher among those using condoms and seroadaptive behaviours. Our findings show antiretroviral-based prevention, either alone or in combination with other strategies, is clearly a component of the HIV prevention landscape for GBM in Montreal. Nevertheless, PrEP uptake remains low, and there is a need to promote its availability more widely.

Modeling an integrated HIV prevention and care continuum to achieve the Ending the HIV Epidemic goals

OBJECTIVE

We sought to evaluate, which combinations of HIV prevention and care activities would have the greatest impact towards reaching the US Ending the HIV Epidemic (EHE) plan goals of HIV incidence reduction.

DESIGN

A stochastic network-based HIV transmission model for men who have sex with men (MSM), calibrated to surveillance estimates in the Atlanta area, a focal EHE jurisdiction.

METHODS

Model scenarios varied HIV screening rates under different assumptions of how HIV-negative MSM would be linked to PrEP initiation, and rates of HIV care linkage and retention for those screening positive.

RESULTS

A ten-fold relative increase in HIV screening rates (to approximately biannual screening for black and Hispanic MSM and quarterly for white MSM) would lead to 43% of infections averted if integrated with PrEP initiation. Improvements focused only on black MSM would achieve nearly the same outcome (37% of infections averted). Improvements to HIV care retention would avert 41% of infections if retention rates were improved ten-fold. If both screening and retention were jointly improved ten-fold, up to 74% of cumulative infections would be averted. Under this scenario, it would take 4 years to meet the 75% EHE goal and 12 years to meet the 90% goal for Atlanta MSM.

CONCLUSION

Reaching the EHE 75% incidence reduction goals by their target dates will require immediate and substantial improvements in HIV screening, PrEP, and ART care retention. Meeting these EHE goals in target jurisdictions like Atlanta will be possible only by addressing the HIV service needs of black MSM.

Dynamics of HIV-1 Molecular Networks Reveal Effective Control of Large Transmission Clusters in an Area Affected by an Epidemic of Multiple HIV Subtypes

This study reconstructed molecular networks of human immunodeficiency virus (HIV) transmission history in an area affected by an epidemic of multiple HIV-1 subtypes and assessed the efficacy of strengthened early antiretroviral therapy (ART) and regular interventions in preventing HIV spread. We collected demographic and clinical data of 2221 treatment-naïve HIV-1–infected patients in a long-term cohort in Shenyang, Northeast China, between 2008 and 2016. HIV pol gene sequencing was performed and molecular networks of CRF01_AE, CRF07_BC, and subtype B were inferred using HIV-TRACE with separate optimized genetic distance threshold. We identified 168 clusters containing ≥ 2 cases among CRF01_AE-, CRF07_BC-, and subtype B-infected cases, including 13 large clusters (≥ 10 cases). Individuals in large clusters were characterized by younger age, homosexual behavior, more recent infection, higher CD4 counts, and delayed/no ART (P < 0.001). The dynamics of large clusters were estimated by proportional detection rate (PDR), cluster growth predictor, and effective reproductive number (R_e). Most large clusters showed decreased or stable during the study period, indicating that expansion was slowing. The proportion of newly diagnosed cases in large clusters declined from 30 to 8% between 2008 and 2016, coinciding with an increase in early ART within 6 months after diagnosis from 24 to 79%, supporting the effectiveness of strengthened early ART and continuous regular interventions. In conclusion, molecular network analyses can thus be useful for evaluating the efficacy of interventions in epidemics with a complex HIV profile.

Greater Levels of Self-Reported Adherence to Pre-Exposure Prophylaxis (PrEP) are Associated with Increased Condomless Sex Among Men Who Have Sex with Men

The effectiveness of pre-exposure prophylaxis (PrEP) against HIV acquisition depends on treatment adherence; however, within-person associations between levels of PrEP adherence and engagement in condomless sex have not been well studied. In the context of a demonstration project, 372 men who have sex with men received once-daily PrEP and completed six study visits over 48 weeks. Two-part growth mixture modeling was used to examine the longitudinal trajectory of condomless anal intercourse (CAI) and self-reports of PrEP adherence, controlling for relevant covariates. Over time, greater PrEP adherence was contemporaneously associated with both a higher likelihood of engaging in any CAI and with a greater number of CAI acts. Substance use was also associated with a higher likelihood of engaging in CAI. Contemporaneous associations between self-reported PrEP adherence and CAI suggest that adherence behaviors may be motivated by the desire to mitigate risk of HIV infection; however, exact directionality is unknown.

Use of HIV Pre-exposure Prophylaxis (PrEP) Associated With Lower HIV Anxiety Among Gay and Bisexual Men in Australia Who Are at High Risk of HIV Infection: Results From the Flux Study

BACKGROUND

Many gay and bisexual men (GBM) experience HIV anxiety, particularly around condomless anal intercourse. HIV pre-exposure prophylaxis (PrEP) is an effective HIV prevention strategy that may reduce HIV anxiety among GBM.

METHODS

The Following Lives Undergoing Change (Flux) Study is a national, online, open-prospective observational study of licit and illicit drug use among GBM in Australia. In 2018, participants responded to newly included items regarding anxiety about HIV transmission. Stratifying GBM as high or low risk as determined by the Australian PrEP Guidelines, we assess whether PrEP use is associated with lower levels of HIV anxiety. Multivariate logistic regression was used to compare factors associated with PrEP use among GBM at high risk (PrEP-eligible) and low risk (PrEP-ineligible) of HIV infection. Results are reported as adjusted odds ratios and corresponding 95% confidence intervals.

RESULTS

Among 1547 men, the mean age was 37.1 years (SD 13.1). Men aged 25 years or younger had higher HIV anxiety scores than older men. Among PrEP-eligible men, men who use PrEP reported lower levels of HIV anxiety (adjusted odds ratio = 0.92; 95% confidence interval = 0.87 to 0.99; P < 0.001). No differences were observed on HIV anxiety among PrEP-ineligible men.

CONCLUSIONS

Among PrEP-eligible men, PrEP use was independently associated with lower levels of HIV anxiety. In addition to avoiding HIV infection, PrEP use may help reduce anxiety among men at risk of HIV. This feature of PrEP could be promoted as part of demand creation initiatives to increase PrEP uptake.

Potential Impact of Targeted HIV Pre-Exposure Prophylaxis Uptake Among Male Sex Workers

Little is known about the potential population-level impact of HIV pre-exposure prophylaxis (PrEP) use among cisgender male sex workers (MSWs), a high-risk subset of cisgender men who have sex with men (MSM). Using an agent-based model, we simulated HIV transmission among cisgender MSM in Rhode Island to determine the impacts of PrEP implementation where cisgender MSWs were equally ("standard expansion") or five times as likely ("focused expansion") to initiate PrEP compared to other cisgender MSM. Without PrEP, the model predicted 920 new HIV infections over a decade, or an average incidence of 0.39 per 100 person-years. In a focused expansion scenario where 15% of at-risk cisgender MSM used PrEP, the total number of new HIV infections was reduced by 58.1% at a cost of $57,180 per quality-adjusted life-year (QALY) gained. Focused expansion of PrEP use among cisgender MSWs may be an efficient and cost-effective strategy for reducing HIV incidence in the broader population of cisgender MSM.

Does Stigma Toward Anal Sexuality Impede HIV Prevention Among Men Who Have Sex With Men in the United States? A Structural Equation Modeling Assessment

INTRODUCTION

Men who have sex with men (MSM) are suboptimally engaged in efficacious HIV interventions, due in part to stigma.

AIM

We sought to validate the Anal Health Stigma Model, developed based on theory and prior qualitative data, by testing the magnitude of associations between measures of anal sex stigma and engagement in HIV prevention practices, while adjusting for covariates.

METHODS

We conducted a cross-sectional online survey of 1,263 cisgender MSM living in the United States and analyzed data with structural equation modeling. We tested a direct path from Anal Sex Stigma to Engagement in HIV Prevention alongside 2 indirect paths, 1 through Anal Sex Concerns and another through Comfort Discussing Anal Sexuality with Health Workers. The model adjusted for Social Support, Everyday Discrimination, and Sociodemographics.

MAIN OUTCOME MEASURE

Engagement in HIV Prevention comprised an ad hoc measure of (i) lifetime exposure to a behavioral intervention, (ii) current adherence to biomedical intervention, and (iii) consistent use of a prevention strategy during recent penile-anal intercourse.

RESULTS

In the final model, anal sex stigma was associated with less engagement (β = -0.22, P < .001), mediated by participants' comfort talking about anal sex practices with health workers (β = -0.52; β = 0.44; both P < .001), adjusting for covariates (R2 = 67%; χ2/df = 2.98, root mean square error of approximation = 0.040, comparative fit index = 0.99 and Tucker-Lewis index = 0.99). Sex-related concerns partially mediated the association between stigma and comfort (β = 0.55; β = 0.14, both P < .001). Modification indices also supported total effects of social support on increased comfort discussing anal sex (β = 0.35, P < .001) and, to a lesser degree, on decreased sex-related concerns (β = -0.10; P < .001).

CLINICAL IMPLICATIONS

Higher stigma toward anal sexuality is associated with less engagement in HIV prevention, largely due to discomfort discussing anal sex practices with health workers.

STRENGTH & LIMITATIONS

Adjustment for mediation in a cross-sectional design cannot establish temporal causality. Self-report is vulnerable to social desirability and recall bias. Online samples may not represent cisgender MSM in general. However, findings place HIV- and health-related behaviors within a social and relational context and may suggest points for intervention in health-care settings.

CONCLUSION

Providers' willingness to engage in discussion about anal sexuality, for example, by responding to questions related to sexual well-being, may function as social support and thereby bolster comfort and improve engagement in HIV prevention. Kutner BA, Simoni JM, King KM, et al. Does Stigma Toward Anal Sexuality Impede HIV Prevention Among Men Who Have Sex With Men in the United States? A Structural Equation Modeling Assessment. J Sex Med 2020;17:477-490.

Potential Impact of Interventions to Enhance Retention in Care During Real-World HIV Pre-Exposure Prophylaxis Implementation

Pre-exposure prophylaxis (PrEP) has the potential to significantly reduce HIV incidence among men who have sex with men (MSM) in the United States. However, the extent to which suboptimal PrEP adherence and retention in care may limit successful implementation is unknown. An agent-based model was used to represent the entire population of MSM in Rhode Island from 2013 to 2017. The impact of potential interventions to improve PrEP adherence and retention in care on HIV transmission was evaluated. Demographics, behaviors, and PrEP adherence and retention in care rates were based on local clinical data. We assumed that 20% of HIV-negative MSM had ever taken PrEP. The primary outcome was HIV incidence over the 5-year period. The model included 23,815 MSM with an estimated 4.1% HIV prevalence based on local surveillance data. An estimated 173.1 new infections occurred over 5 years [95% simulation interval (SI): 171.5-174.7], including 29.1 new infections among individuals who had ever initiated PrEP (95% SI: 28.6-29.7). Interventions that improved retention in PrEP care by an odds of 5.0 compared with the base case maximized reductions in HIV incidence among MSM who had ever initiated PrEP by 37.5%. Interventions focusing on improving PrEP adherence had little to no effect on HIV incidence, regardless of intervention efficacy. Retention in care is a critical component of the PrEP care continuum. Interventions that improve retention in PrEP care may lead to greater reductions in population-level HIV incidence compared with interventions focused exclusively on adherence.

Gonorrhoea and chlamydia diagnosis as an entry point for HIV pre-exposure prophylaxis: a modelling study

OBJECTIVES

Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) increase the risk of HIV transmission among men who have sex with men (MSM). Diagnosis of NG/CT may provide an efficient entry point for prevention of HIV through the delivery of pre-exposure prophylaxis (PrEP); however, the additional population-level impact of targeting PrEP to MSM diagnosed with NG/CT is unknown.

DESIGN

An agent-based simulation model of NG/CT and HIV cocirculation among MSM calibrated against census data, disease surveillance reports and the US National HIV Behavioral Surveillance study.

SETTING

Baltimore City, Maryland, USA.

INTERVENTIONS

PrEP implementation was modelled under three alternative scenarios: (1) PrEP delivery at NG/CT diagnosis (targeted delivery), (2) PrEP evaluation at NG/CT screening/testing and (3) PrEP evaluation in the general community (untargeted).

MAIN OUTCOME

The projected incidence of HIV after 20 years of PrEP delivery under two alternatives: when equal numbers of MSM are (1) screened for PrEP or (2) receive PrEP in each year.

RESULTS

Assuming 60% uptake and 60% adherence, targeting PrEP to MSM diagnosed with NG/CT could reduce HIV incidence among MSM in Baltimore City by 12.4% (95% uncertainty range (UR) 10.3% to 14.4%) in 20 years, relative to no PrEP. Expanding the coverage of NG/CT screening (such that individuals experience a 50% annual probability of NG/CT screening and evaluation for PrEP on NG/CT diagnosis) can further increase the impact of targeted PrEP to generate a 22.0% (95% UR 20.1% to 23.9%) reduction in HIV incidence within 20 years. When compared with alternative implementation scenarios, PrEP evaluation at NG/CT diagnosis increased impact of PrEP on HIV incidence by 1.5(95% UR 1.1 to 1.9) times relative to a scenario in which PrEP evaluation happened at the time of NG/CT screening/testing and by 1.6 (95% UR 1.2 to 2.2) times relative to evaluating random MSM from the community.

CONCLUSIONS

Targeting MSM infected with NG/CT increases the efficiency and effectiveness of PrEP delivery. If high levels of sexually transmitted infection screening can be achieved at the community level, NG/CT diagnosis may be a highly effective entry point for PrEP initialisation.

A Randomized Controlled Pilot Study of a Culturally-Tailored Counseling Intervention to Increase Uptake of HIV Pre-exposure Prophylaxis Among Young Black Men Who Have Sex with Men in Washington, DC

Daily emtricitabine/tenofovor is effective at preventing HIV acquisition and is approved for HIV pre-exposure prophylaxis (PrEP). Blacks in the United States have a disproportionately high rate of HIV, and uptake of PrEP has been very low in this population. We conducted a pilot study in a high-prevalence city to test whether a culturally-tailored counseling center for young Black men who have sex with men (BMSM) positively impacted their access and uptake of PrEP. 50 young BMSM were randomized to either a PrEP counseling center group or a control group, and were then encouraged to obtain PrEP from a PrEP provider. At the end of 3 month study, six participants in the intervention group compared with none in the control group had initiated PrEP (p = 0.02). This pilot study demonstrates that a culturally-tailored counseling center might be an effective at increasing the uptake of PrEP in young BMSM.

Qualitative Consumer Research on Acceptance of Long-Acting Pre-Exposure Prophylaxis Products Among Men Having Sex with Men and Medical Practitioners in the United States

Pre-exposure prophylaxis (PrEP) with oral Truvada^® prevents HIV infection. However, the adherence to pill taking required for efficacy has sparked interest in developing new antiretroviral delivery systems that decrease such demands. Long-acting formulations, such as injections and implants, represent promising options that require less frequent adherence. It is important, however, that development of these new modalities be driven by understanding of the value seen in them by target users to maximize their uptake. To identify the key product features that impact user acceptance, we used a three-phase marketing research approach. In this study, we describe the results of the first-phase, qualitative focus group research performed in Chicago and San Francisco that explored subjective perceptions of oral versus alternative PrEP modalities among men having sex with men (MSM) and medical practitioners caring for MSM. Data revealed that potential value in long-acting PrEP lies more in simplifying the lives of users rather than in making them more confident in their adherence. The results provide an important guidance for designing and promoting these future long-acting products to enhance their contribution to increasing the current limited uptake of PrEP that will better stem the HIV epidemic.

Improving the impact of HIV pre-exposure prophylaxis implementation in small urban centers among men who have sex with men: An agent-based modelling study

Objectives

Identifying prescribing strategies that improve the efficiency of PrEP should increase its impact at the population level. This study identifies PrEP allocation criteria that most effectively reduce 10-year HIV incidence by 25%, in accordance with the US National HIV/AIDS Strategy’s goal for the proportionate reduction in new diagnoses.

Methods

We used a discrete-time stochastic agent-based model to simulate several PrEP engagement strategies. The model represented MSM aged 15–74 in Rhode Island and was calibrated to statewide prevalence from 2009–2014. We simulated HIV transmission in the absence of PrEP and compared the following PrEP engagement scenarios: 1) allocation to the current patient population; 2) random allocation; 3) allocation to MSM with greater than 5 sexual partners in one year; 4) allocation to MSM with greater than 10 sexual partners in one year.

For each scenario and coverage level we estimated the number and proportion of infections averted and the person-years on PrEP per averted infection.

Results

In 2014, HIV prevalence before PrEP implementation was between 4% and 5%. In the No PrEP scenario 826 new infections (95% simulation limits [SL]: 711, 955) occurred over 10 years, with an incidence rate of 3.51 per 1000 person-years (95% SL: 3.00, 4.08). Prevalence rose to 7.4% (95% SL: 6.7, 8.1). None of the PrEP scenarios reduced new HIV infections by 25% while covering less than 15% of the HIV-uninfected population. At 15% coverage, allocating PrEP to the current patient population, MSM with greater than 5 sexual partners in a year, and MSM with greater than 10 partners reduced new infections by at least 25%, requiring 161 (95% SL: 115, 289), 150 (95% SL: 107, 252), and 128 (95% SL: 100, 184) person-years on PrEP per averted infection, respectively.

Conclusions

Engaging MSM with high numbers of sexual partners would improve the population-level impact and efficiency of PrEP in settings where PrEP coverage remains low. However, the sustained population-level PrEP coverage needed to reduce new infections by 25% is substantially higher than current levels of PrEP uptake.

Molecular Epidemiology of the HIV Epidemic in Three German Metropolitan Regions - Cologne/Bonn, Munich and Hannover, 1999-2016

Using HIV sequence data to characterize clusters of HIV transmission may provide insight into the epidemic. Phylogenetic and network analyses were performed to infer putative relationships between HIV-1 partial pol sequences from 2,774 individuals receiving care in three German regions between 1999-2016. The regions have in common that they host some of the largest annual festivals in Europe (Carnival and Oktoberfest). Putative links with sequences (n = 150,396) from the Los Alamos HIV Sequence database were evaluated. A total of 595/2,774 (21.4%) sequences linked with at least one other sequence, forming 184 transmission clusters. Clustering individuals were significantly more likely to be younger, male, and report sex with men as their main risk factor (p < 0.001 each). Most clusters (77.2%) consisted exclusively of men; 41 (28.9%) of these included men reporting sex with women. Thirty-two clusters (17.4%) contained sequences from more than one region; clustering men were significantly more likely to be in a position bridging regional HIV epidemics than clustering women (p = 0.027). We found 236 clusters linking 547 sequences from our sample with sequences from the Los Alamos database (n = 1407; 31% from other German centres). These results highlight the pitfalls of focusing HIV prevention efforts on specific risk groups or specific locales.

Preexposure Prophylaxis of HIV Infection: the Role of Clinical Practices in Ending the HIV Epidemic

PURPOSE OF REVIEW

The aim of this study is to summarise the recent evidence from high-income settings about providers' ability to deliver on the UNAIDS goal of at least three million people at substantial risk of HIV infection with PrEP by 2020, including awareness and knowledge about PrEP, willingness to prescribe PrEP, current levels of prescribing and service delivery models and issues.

RECENT FINDINGS

Awareness about PrEP among health providers is growing, but at different pace depending on provider type. HIV and sexual health specialists are more likely to have knowledge about PrEP than generalists, and to be willing to prescribe it, mainly because of their closer contact with people at high risk for HIV and better risk assessment skills. There is still no consensus as to who should be responsible for providing PrEP, but clearly all hands on deck will be useful in delivering on the international target of three million people at substantial risk for HIV on PrEP by 2020. Only about 5% of the target has been reached so far. Local guidance and large-scale education and information programs for clinicians will be necessary to upskill health providers. High cost of PrEP is still a major barrier for its broad implementation, even in countries were PrEP roll-out has started. Health services are facing major structural challenges due to implementation of PrEP services to a substantial volume of patients. The early implementation experiences demonstrated that PrEP can be successfully delivered across a variety of settings, and a broad range of strategies and models of care can streamline PrEP delivery. Education of the providers and PrEP cost solutions will be essential for rapid roll-out of PrEP.

Prevalence of actual uptake and willingness to use pre-exposure prophylaxis to prevent HIV acquisition among men who have sex with men in Hong Kong, China

OBJECTIVES

This study was to investigate the prevalence of actual uptake of pre-exposure prophylaxis (PrEP), willingness to use daily oral PrEP under two cost scenarios, and potential issues related to PrEP use among men who have sex with men (MSM) with HIV negative/unknown sero-status in Hong Kong, China. Factors associated with the two measures of willingness were also investigated.

METHODS

403 eligible MSM completed the anonymous venue-based face-to-face interview/telephone interview.

RESULTS

Only 1% had ever used PrEP. After being briefed about some facts of PrEP, the prevalence of willingness to use daily oral PrEP was 7.7% if they could purchase PrEP at private hospitals/clinics at HK$8,000 (US$1,032)/month (market rate) and 45.2% if free PrEP was provided by public hospitals/clinics in Hong Kong (free PrEP). After adjusted for significant background variables, significant factors of these two measures of willingness included: (1) number of correct responses to knowledge on PrEP, (2) perceived risk of HIV infection in the next six months, and (3) constructs of the Theory of Planned Behavior: positive and negative attitudes toward PrEP, perceived their significant others would support them take PrEP (perceived subjective norm), perceived number of local MSM who were willing to take PrEP (perceived descriptive norm), and confidence in using PrEP under the two scenarios (perceived behavioral control). Among all participants, 9.7% and 25.1% would start and discontinue using PrEP without consulting doctors; 26.0% would not take PrEP daily if it was provided for free, and 42.4% would not take up HIV testing every 3 months after using PrEP.

CONCLUSION

Different strategies should be considered for promoting PrEP at market rate and if free PrEP is made available. Future promotion should increase their knowledge about PrEP, modify their perceptions related to HIV and PrEP, and address some potential issues related to PrEP use.

The Effect of PrEP on HIV Incidence Among Men Who Have Sex With Men in the Context of Condom Use, Treatment as Prevention, and Seroadaptive Practices

BACKGROUND

HIV preexposure prophylaxis (PrEP) is an effective tool in preventing HIV infection among high-risk men who have sex with men (MSM). It is unknown how effective PrEP is in the context of other implemented HIV prevention strategies, including condom use, seroadaption, and treatment as prevention (TasP). We evaluate the impact of increasing uptake of PrEP in conjunction with established prevention strategies on HIV incidence in a high-risk population of MSM through simulation.

METHODS

Agent-based simulation models representing the sexual behavior of high-risk, urban MSM in the United States over the period of 1 year were used to evaluate the effect of PrEP on HIV infection rates. Simulations included data for 10,000 MSM and compared increasing rates of PrEP uptake under 8 prevention paradigms: no additional strategies, TasP, condom use, seroadaptive behavior, and combinations thereof.

RESULTS

We observed a mean of 103.2 infections per 10,000 MSM in the absence of any prevention method. PrEP uptake at 25% without any additional prevention strategies prevented 30.7% of infections. In the absence of PrEP, TasP, condom use, and seroadaptive behavior independently prevented 27.1%, 48.8%, and 37.7% of infections, respectively, and together prevented 72.2%. The addition of PrEP to the 3 aforementioned prevention methods, at 25% uptake, prevented an additional 5.0% of infections.

CONCLUSIONS

To achieve a 25% reduction in HIV infections by 2020, HIV prevention efforts should focus on significantly scaling up access to PrEP in addition to HIV testing, access to antiretroviral therapy, and promoting condom use.

HIV transmission and pre-exposure prophylaxis in a high risk MSM population: A simulation study of location-based selection of sexual partners

OBJECTIVE

In France, indications for pre-exposure prophylaxis (PrEP) for HIV prevention are based on individual-level risk factors for HIV infection. However, the risk of HIV infection may also depend on characteristics of sexual partnerships. Here we study how place-based selection of partners change transmission and the overall efficiency of PrEP.

METHODS

We used the PREVAGAY survey of sexual behavior and HIV serostatus in men who have sex with men (MSM) in a Parisian district to look for associations between sexual network characteristics and HIV infection. We then simulated HIV transmission in a high-risk MSM population. We used information about venues visited to meet casual sexual partners (clubs, backrooms or saunas) to define sexual networks. We then simulated HIV transmission in these networks and assessed the impact of PrEP in this population.

RESULTS

In the PREVAGAY study, we found that HIV serostatus changed with the type of venues visited, in addition to other individual risk factors. In simulations, we found similar differences in HIV incidence when the choice of venues visited was not random. The use of PrEP allowed reducing incidence, irrespective of the venues visited by PrEP users. However, with the same amount of PrEP, the number of infections adverted could almost double depending on network structure and venues visited by PrEP users.

CONCLUSION

This study shows that characteristics of the sexual network structure can strongly impact the effectiveness of PrEP interventions. These should be considered further to refine individual risk assessment and maximize the effect of individual-based prevention policies.

Pre-exposure prophylaxis for MSM and transgender persons in early adopting countries

: Pre-exposure prophylaxis (PrEP) is a potent and underutilized HIV prevention tool. In this paper we review the state of knowledge regarding PrEP implementation for men who have sex with men and transgender persons in early adopting countries. We focus on implementation of PrEP in demonstration projects and clinical care, and describe the status of PrEP availability and uptake. We report on approaches to identifying appropriate PrEP candidates in real-world settings and on best practices for clinical monitoring. This includes the exclusion of undiagnosed HIV infection prior to PrEP initiation and longitudinal measurement of renal function, in light of safety data. Since adherence is the primary factor moderating the effectiveness of PrEP, we discuss effective adherence support interventions. Additionally, we review the evidence for risk compensation with PrEP use and opportunities to provide PrEP as part of comprehensive and inclusive preventive health programs. We summarize cost-effectiveness studies, including their variable conclusions because of differing underlying assumptions, and discuss the importance of budgetary impact for public health programs and health care insurers. Further, we emphasize a need for greater engagement of health care providers in PrEP to increase access. We conclude with recommendations for ways to improve future efforts at implementing PrEP.