Elimination prospects of the Dutch HIV epidemic among men who have sex with men in the era of preexposure prophylaxis

Lenacapavir to prevent HIV infection: current prices versus estimated costs of production

BACKGROUND

Despite improvements in treatment and oral pre-exposure prophylaxis (PrEP) access, 1.3 million people acquired HIV in 2022. Six-monthly lenacapavir PrEP could benefit tens of millions of people at high risk of infection. However, prices are currently up to $44 819 per person per year (pppy).

OBJECTIVES

We projected minimum lenacapavir pricing based on generic mass production and a Cost-Plus (Cost+) model.

METHODS

Current active pharmaceutical ingredient (API) and key starting materials (KSMs) costs were obtained from export databases. The routes of synthesis (ROS) were analysed to project a cost of goods (COGs). Formulation, vials and profit margin costs were included using standardized algorithms and Cost+ pricing. We estimated prices with scale-up to supply 1 million then 10 million treatment-years, comparing this with national list prices.

RESULTS

The lenacapavir API is currently exported from India for $64 480/kg on 1 kg scale. Based on the ROS and KSMs, API COGs of $25 000/kg and $10 000/kg are achievable for a committed demand of 1 million (2 million tonnes/annum of API) and 10 million treatment-years, respectively. Including formulation steps, injectable lenacapavir could be mass produced for approximately $94 pppy for 1 million and $41 for 10 million treatment-years, if voluntary licences are in place and competition between generic suppliers substantially improves. Greater scale-up with improvements in manufacturers' ROS could reduce prices further. Currently lenacapavir costs $25 395-44 819 pppy.

CONCLUSIONS

Lenacapavir could be mass produced for <$100 pppy at launch. Voluntary licensing and multiple suppliers are required to achieve these low prices. This mechanism is already in place for other antiretrovirals. To date, Gilead has not agreed lenacapavir voluntary licences with the Medicines Patent Pool.

The Best Predictor of Future Behavior May Be the Past: Exploring Behavior Change in Men Who Have Sex with Men Using Pre-exposure Prophylaxis in the Netherlands

Pre-exposure prophylaxis (PrEP) use prevents HIV transmission, and may lead to changes in sexual behavior. We aimed to explore sexual behavior over time, and identify predictors of behavior change in men who have sex with men (MSM) using PrEP at sexual health centers (SHC) in the Netherlands. We used longitudinal data from the national STI surveillance database (January 2018-June 2021) of HIV-negative MSM who first initiated PrEP in the national PrEP pilot. We modelled behavior change after PrEP initiation, and identified predictors of behavior change using multi-state Markov models. The probability of stopping group sex, chemsex, use of poppers or erection stimulants, and having ≥ 10 partners in the past 6 months among included MSM (n = 4,349, n SHC visits = 21,820) was higher compared to the probability of starting with these behaviors after PrEP initiation. However, MSM who used condoms consistently during anal sex had a high probability of changing to inconsistent condom use (0.8) at the next visit, and inconsistent condom users mostly remained inconsistent (0.8). First visit, visiting the SHC more often (vs. regular), and STI diagnosis were predictors of starting or continuing with most of the behaviors associated with increased risk. Behavior change was less likely among older participants (> 34 compared to ≤ 34 years), and during COVID-19 lockdown and post-lockdown periods compared to pre-COVID-19. Although condom use decreased over time, transitions towards stopping with other behaviors associated with increased likelihood of acquiring an STI after PrEP initiation were common. This may suggest increased sexual empowerment, especially among younger MSM. Predictors of behavior change may help to identify MSM who are likely to start with or continue to engage in these behaviors in the near future and to provide suitable and timely counselling about behavior and PrEP adherence.

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.

A psychosocial network approach studying biomedical HIV prevention uptake between 2017 and 2019

Biomedical HIV-prevention strategies (BmPS) among men who have sex with men (MSM), such as pre-exposure prophylaxis (PrEP) and viral load sorting (VLS), are essential but relatively new and their uptake gradual. Using an extension of the causal attitude network approach, we investigated which beliefs are related to uptake of PrEP and VLS at each time-point. We included 632 HIV-negative MSM from the Amsterdam Cohort Studies from four data-waves between 2017 and 2019. We estimated weighted, undirected networks for each time-point, where we included pairwise interactions of PrEP and VLS uptake and related beliefs. PrEP use increased from 10 to 31% (p < 0.001), while VLS was reported by 7-10% at each time-point. Uptake of both BmPS was directly related to the perceived positive impact of the strategy on one's quality of sex life and perceived supportive social norms. Overall network structure differed between time points, specifically in regard to PrEP. At earlier time points, perceptions of efficacy and affordability played an important role for PrEP uptake, while more recently social and health-related concerns became increasingly important.The network structure differed across data-waves, suggesting specific time changes in uptake motives. These findings may be used in communication to increase prevention uptake.

Infectious Disease Modelling of HIV Prevention Interventions: A Systematic Review and Narrative Synthesis of Compartmental Models

BACKGROUND

The HIV epidemic remains a major public health problem. Critical to transmission control are HIV prevention strategies with new interventions continuing to be developed. Mathematical models are important for understanding the potential impact of these interventions and supporting policy decisions. This systematic review aims to answer the following question: when a new HIV prevention intervention is being considered or designed, what information regarding it is necessary to include in a compartmental model to provide useful insights to policy makers? The primary objective of this review is therefore to assess suitability of current compartmental HIV prevention models for informing policy development.

METHODS

Articles published in EMBASE, Medline, Econlit, and Global Health were screened. Included studies were identified using permutations of (i) HIV, (ii) pre-exposure prophylaxis (PrEP), circumcision (both voluntary male circumcision [VMMC] and early-infant male circumcision [EIMC]), and vaccination, and (iii) modelling. Data extraction focused on study design, model structure, and intervention incorporation into models. Article quality was assessed using the TRACE (TRAnsparent and Comprehensive Ecological modelling documentation) criteria for mathematical models.

RESULTS

Of 837 articles screened, 48 articles were included in the review, with 32 unique mathematical models identified. The substantial majority of studies included PrEP (83%), whilst fewer modelled circumcision (54%), and only a few focussed on vaccination (10%). Data evaluation, implementation verification, and model output corroboration were identified as areas of poorer model quality. Parameters commonly included in the mathematical models were intervention uptake and effectiveness, with additional intervention-specific common parameters identified. We identified key modelling gaps; critically, models insufficiently incorporate multiple interventions acting simultaneously. Additionally, population subgroups were generally poorly represented-with future models requiring improved incorporation of ethnicity and sexual risk group stratification-and many models contained inappropriate data in parameterisation which will affect output accuracy.

CONCLUSIONS

This review identified gaps in compartmental models to date and suggests areas of improvement for models focusing on new prevention interventions. Resolution of such gaps within future models will ensure greater robustness and transparency, and enable more accurate assessment of the impact that new interventions may have, thereby providing more meaningful guidance to policy makers.

Scaling up preexposure prophylaxis to maximize HIV prevention impact

PURPOSE OF REVIEW

Ten years since the first regulatory approval of oral HIV preexposure prophylaxis (PrEP), this review summarizes PrEP uptake, the role of ambitious PrEP targets, emerging evidence of impact on the HIV epidemic and innovative approaches to increasing PrEP uptake.

RECENT FINDINGS

PrEP uptake among people at risk of HIV has been slow, but has accelerated in recent years, particularly in gay and bisexual men in a limited number of high-income settings and recently in heterosexuals at risk of HIV in sub-Saharan Africa. However, UNAIDS 2020 PrEP targets and HIV prevention targets were missed by large margins. Although UNAIDS testing and treatment targets have galvanised public health action, in contras, PrEP targets have been lower profile and insufficiently ambitious. Parts of the USA, Australia and the UK with high PrEP coverage have demonstrated striking reductions in HIV infection at the population level, as PrEP is introduced at scale. Scaling up PrEP uptake will require innovations in PrEP promotion, simplified models of care, improved adherence interventions, improved choice in the form of longer-acting PrEP and interventions to ensure that all those who can benefit from PrEP can access it.

SUMMARY

PrEP is a revolutionary HIV prevention tool, which if ambitiously scaled up could drive HIV transmission towards elimination. Highly publicized and ambitious PrEP targets could help drive this.

Awareness of, Willingness to Take PrEP and Its Actual Use Among Belgian MSM at High Risk of HIV Infection: Secondary Analysis of the Belgian European MSM Internet Survey

We examined PrEP awareness, willingness to take it and early PrEP use among men who have sex with men (MSM) at increased risk of HIV acquisition in Belgium. This analysis of the Belgian EMIS online data of 2017-2018 adopts a cascade approach, with the following steps quantified as conditional probabilities: being eligible for, aware of, willing to take PrEP, and PrEP use. One out of three MSM was eligible to use PrEP according to the operationalized Belgian reimbursement criteria. PrEP awareness was lower among socioeconomically vulnerable MSM, MSM living outside large cities, MSM who were less open about their sexuality and those who did not identify as gay or homosexual. A lack of PrEP knowledge, a higher self-efficacy regarding safe sex, having a steady partner and reporting more symptoms of depression were related to unwillingness to use PrEP. Among those willing to take PrEP, less than one third were actually using PrEP. Not using PrEP was associated with living in small cities and experiencing financial problems.

Trends in Sexual Behavior and Sexually Transmitted Infections After Initiating Human Immunodeficiency Virus Pre-Exposure Prophylaxis in Men Who Have Sex with Men from Amsterdam, the Netherlands: A Longitudinal Exposure-Matched Study

Men who have sex with men (MSM) initiating human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) may increase condomless anal sex (CAS) and number of partners, and, consequently, more often acquire sexually transmitted infections (STIs). Using data from the Amsterdam Cohort Studies, we compared sexual behavior and STI among MSM after PrEP-initiation with controls not initiating PrEP. The MSM reported on sexual behavior and were tested for HIV, chlamydia, gonorrhea, and syphilis semi-annually. We matched MSM who initiated PrEP between January 1, 2015 and December 31, 2019 1:1 to MSM who did not use time-dependent propensity scores based on age, sexual behavior, and STI. Primary end-points were number of casual partners, and proportion with CAS and receptive CAS (rCAS) with casual partners, sexualized drug use (SDU), any STI, and anal STI. We modeled end-points during the 4 years before and 2 years after PrEP-initiation or matched PrEP-initiation timepoint by using logistic regression (dichotomous end-points) or negative binomial regression (count end-point), adjusted for calendar year. Two hundred twenty-eight out of the 858 (26.6%) MSM initiated PrEP. We matched 198 out of 228 (86.8%) to a control. Before PrEP-initiation, end-points increased over time in both groups, with no statistically significant difference. The odds of CAS, rCAS, and anal STI were on average higher after than before PrEP-initiation in PrEP initiators, whereas after versus before differences were not observed in controls. After PrEP-initiation, PrEP initiators had statistically significantly more casual partners, and higher odds of CAS, rCAS, SDU, any STI, and anal STI than controls. These findings support frequent STI screening and counseling in MSM using PrEP.

Transitions Between Preexposure Prophylaxis Eligibility States and HIV Infection in the Lisbon Cohort of HIV-Negative Men Who Have Sex With Men: A Multistate Model Analysis

We aimed to describe transitions between preexposure prophylaxis (PrEP) eligibility and human immunodeficiency virus (HIV) infection among HIV-negative men who have sex with men (MSM). We used data from 1,885 MSM, who had not used PrEP, enrolled in the Lisbon Cohort of MSM, with at least 2 consecutive measurements of PrEP eligibility from 2014-2020. A time-homogeneous Markov multistate model was applied to describe the transitions between states of PrEP eligibility-eligible and ineligible-and from these to HIV infection (HIV). The intensities of the transitions were closer for ineligible-to-eligible and eligible-to-ineligible transitions (intensity ratio, 1.107, 95% confidence interval (CI): 1.080, 1.176), while the intensity of the eligible-to-HIV transition was higher than that for ineligible-to-HIV transition (intensity ratio, 9.558, 95% CI: 0.738, 65.048). The probabilities of transitions increased with time; for 90 days, the probabilities were similar for the ineligible-to-eligible and eligible-to-ineligible transitions (0.285 (95% CI: 0.252, 0.319) vs. 0.258 (95% CI: 0.228, 0.287)), while the eligible-to-HIV transition was more likely than ineligible-to-HIV (0.004 (95% CI: 0.003, 0.007) vs. 0.001 (95% CI: 0.001, 0.008)) but tended to become closer with time. Being classified as ineligible was a short-term indicator of a lower probability of acquiring HIV. Once an individual moved to eligible, he was at a higher risk of seroconversion, demanding a timely delivery ofPrEP.

Time for change: Transitions between HIV risk levels and determinants of behavior change in men who have sex with men

As individual sexual behavior is variable over time, the timing of interventions might be vital to reducing HIV transmission. We aimed to investigate transitions between HIV risk levels among men who have sex with men (MSM), and identify determinants associated with behavior change. Participants in a longitudinal cohort study among HIV-negative MSM (Amsterdam Cohort Studies) completed questionnaires about their sexual behavior during biannual visits (2008-2017). Visits were assigned to different HIV risk levels, based on latent classes of behavior. We modelled transitions between risk levels, and identified determinants associated with these transitions at the visit preceding the transition using multi-state Markov models. Based on 7,865 visits of 767 participants, we classified three risk levels: low (73% of visits), medium (22%), and high risk (5%). For MSM at low risk, the six-month probability of increasing risk was 0.11. For MSM at medium risk, the probability of increasing to high risk was 0.08, while the probability of decreasing to low risk was 0.33. For MSM at high risk, the probability of decreasing risk was 0.43. Chemsex, erection stimulants and poppers, high HIV risk perception, and recent STI diagnosis were associated with increased risk at the next visit. High HIV risk perception and young age were associated with decreasing risk. Although the majority of MSM showed no behavior change, a considerable proportion increased HIV risk. Determinants associated with behavior change may help to identify MSM who are likely to increase risk in the near future and target interventions at these individuals, thereby reducing HIV transmission.

Can HIV epidemics among MSM be eliminated through participation in preexposure prophylaxis rollouts?

OBJECTIVE

To study the conditions under which preexposure prophylaxis (PrEP) coverage can eliminate HIV among MSM in the Paris region.

DESIGN

Mathematical modeling.

METHODS

We propose an innovative approach, combining a transmission model with a game-theoretic model, for decision-making about PrEP use. Individuals at high risk of HIV infection decide to use PrEP, depending on their perceived risk of infection and the relative cost of using PrEP versus antiretroviral treatment (ART), which includes monetary and/or nonmonetary aspects, such as price and access model of PrEP, consequences of being infected and lifelong ART.

RESULTS

If individuals assessed correctly their infection risk, and the cost of using PrEP were sufficiently low, then the PrEP rollout could lead to elimination. Specifically, assuming 86% PrEP effectiveness, as observed in two clinical trials, a minimum PrEP coverage of 55% [95% confidence interval (CI) 43-64%] among high-risk MSM would achieve elimination in the Paris region. A complete condom drop by MSM using PrEP slightly increases the minimum PrEP coverage required for elimination, by ∼1%, whereas underestimation of their own HIV infection risk would require PrEP programs reduce the cost of using PrEP by a factor ∼2 to achieve elimination.

CONCLUSION

Elimination conditions are not yet met in the Paris region, where at most 47% of high-risk MSM were using PrEP as of mid-2019. Further lowering the cost of PrEP and promoting a fair perception of HIV risk are required and should be maintained in the long-run, to maintain elimination status.

HIV Viral Suppression and Pre-exposure Prophylaxis in HIV and Syphilis Contact Tracing Networks: An Analysis of Disease Surveillance and Prescription Claims Data

BACKGROUND

HIV and syphilis contact tracing networks offer efficient platforms for HIV treatment and prevention interventions, but intervention coverage within these networks has not been characterized.

SETTING

HIV and syphilis sexual contact tracing networks among men who have sex with men (MSM) in North Carolina (NC).

METHODS

Using surveillance data, we identified 2 types of "network events" that occurred between January 2013 and June 2017 among MSM in NC: being diagnosed with early syphilis or being named as a recent sexual contact of a person diagnosed with HIV or early syphilis. We estimated prevalent and incident HIV viral suppression among persons diagnosed with HIV before the network event, and we assessed the effect of contact tracing services on a 6-month cumulative incidence of viral suppression among previously HIV-diagnosed, virally unsuppressed persons. Using linked prescription claims data, we also evaluated prevalent and incident pre-exposure prophylaxis (PrEP) use in an insured subset of HIV-negative network members.

RESULTS

Viral suppression prevalence among previously HIV-diagnosed persons was 52.6%. The 6-month cumulative incidence of viral suppression was 35.4% overall and 13.1 (95% confidence interval: 8.8 to 17.4) percentage points higher among persons reached than among those not reached by contact tracing services. Few HIV-negative persons had prevalent (5.4%) or incident (4.1%) PrEP use in the 6 months before or after network events, respectively.

CONCLUSIONS

Suboptimal viral suppression and PrEP use among MSM in NC in HIV/syphilis contact tracing networks indicate a need for intensified intervention efforts. In particular, expanded services for previously HIV-diagnosed persons could improve viral suppression and reduce HIV transmission within these networks.

Who falls between the cracks? Identifying eligible PrEP users among people with Sub-Saharan African migration background living in Antwerp, Belgium

Introduction

This study produces an estimate of the proportion of eligible PrEP users among people of Sub-Saharan African background based on the Belgian PrEP eligibility criteria and examines associations with socio-economic and demographic characteristics.

Methods

We performed logistic regression analysis on data of a representative community-based survey conducted among Sub-Saharan African communities (n = 685) living in Antwerp.

Results

Almost a third (30.3%) of the respondents were eligible to use PrEP. Those who were male, single, lower educated, undocumented, and had experienced forced sex were more likely to be eligible for PrEP use. The findings highlight the importance of taking intra-, interpersonal and structural HIV risk factors into account.

Conclusions

The study shows high unmet PrEP needs in this population, especially among those with high vulnerability for HIV acquisition. A better understanding of barriers to PrEP use in this population group is needed to allow for equitable access.

The continuing HIV epidemic among men who have sex with men and transgender women in the ASEAN region: implications for HIV policy and service programming

Men who have sex with men (MSM) in Western urban areas have seen substantive decreases in new diagnoses of HIV infection. This paper explores whether such declines are present among MSM and transgender women (TGW) in Southeast Asia and discusses implications for HIV policies and programming. A scoping review was conducted of scientific publications and selected documents regarding the spread of HIV infection among MSM and TGW in major urban centres of the Association of Southeast Asian Nations (ASEAN) region. Continued high HIV prevalence and incidence among MSM are found in integrated behavioural and biological surveillance (IBBS) and research studies. HIV prevalence among MSM under IBBS decreased only in Bangkok from 28.6% in 2014 to 10.3% in 2018, whereas it was increasing in Kuala Lumpur, Ho Chi Minh City, Vientiane, and Phnom Penh. HIV/AIDS case reports regarding new HIV infection diagnoses among MSM have started to decrease in Singapore since 2011 and have been plateauing in Metropolitan Manila since 2017. Where data were available, it was found that HIV prevalence among TGW was high and if IBBS was conducted, it was increasing. HIV prevalence among TGW under IBBS in Jakarta had risen to 34.0% (2015) and 14.0% (2019) in Phnom Penh. These findings suggest that most ASEAN member states have so far failed to effectively implement and scale-up scientifically proven biomedical HIV prevention measures and counter stigma and discrimination that impedes access to appropriate HIV prevention and treatment services for MSM and TGW.

Introducing pre-exposure prophylaxis to prevent HIV acquisition among men who have sex with men in Sweden: insights from a mathematical pair formation model

OBJECTIVES

Since 2017, the Public Health Agency of Sweden recommends that pre-exposure prophylaxis (PrEP) for HIV should be offered to high-risk individuals, in particular to men who have sex with men (MSM). The objective of this study is to develop a mathematical model investigating the effect of introducing PrEP to MSM in Sweden.

DESIGN

A pair formation model, including steady and casual sex partners, is developed to study the impact of introducing PrEP. Two groups are included in the model: sexually high active MSM and sexually low active MSM. Three mixing assumptions between the groups are considered.

SETTING

A gay-friendly MSM HIV/sexually transmitted infection testing clinic in Stockholm, Sweden. This clinic started offering PrEP to MSM in October 2018.

PARTICIPANTS

The model is calibrated according to detailed sexual behaviour data gathered in 2015 among 403 MSM.

RESULTS

By targeting sexually high active MSM, a PrEP coverage of 3.5% of the MSM population (10% of all high actives) would result in the long-term HIV prevalence to drop considerably (close to 0%). While targeting only low actives would require a PrEP coverage of 35% for a similar reduction. The main effect of PrEP is the reduced susceptibility, whereas the increased HIV testing rate (every third month) among PrEP users plays a lesser role.

CONCLUSIONS

To create a multifaceted picture of the effects of interventions against HIV, we need models that include the different stages of HIV infection and real-world data on detailed sexual behaviour to calibrate the mathematical models. Our findings conclude that targeting HIV high-risk individuals, within HIV risk populations such as MSM, with PrEP programmes could greatly decrease the long-term HIV prevalence in Sweden. Therefore, risk stratification of individuals is of importance in PrEP implementation programmes, to ensure optimising the effect and cost-effectiveness of such programmes.

Diverging trends in incidence of HIV versus other sexually transmitted infections in HIV-negative MSM in Amsterdam

OBJECTIVES

We investigated changes in incidence rates of HIV and sexually transmitted infections (STIs) and trends in sexual behavior in MSM from 2009 to 2017.

DESIGN

Open prospective cohort study.

METHODS

HIV-negative MSM enrolled in the Amsterdam Cohort Studies were included. Participants semiannually completed a questionnaire on sexual behavior and were tested for HIV-1, syphilis, and urethral, anal and pharyngeal chlamydia and gonorrhea. Time trends in incidence rates were analyzed using exponential survival models.

RESULTS

During follow-up, 42 of 905 MSM acquired HIV. The HIV incidence rate was 1.9/100 person-years [95% confidence interval (CI) 1.0-3.7] in 2009 and decreased to 0.5/100 person-years (95% CI 0.2-1.4) in 2017 (P = 0.03). The largest decrease was observed in participants aged at least 35 years (P = 0.005), while the trend remained stable in 18-34 year olds (P = 0.4). The incidence rate for any bacterial STI was 16.8/100 person-years (95% CI 13.4-21.0) in 2010, and increased to 33.1/100 person-years (95% CI 29.0-37.9) in 2017 (P < 0.001). Between 2009 and 2017, the percentage reporting condomless anal sex with casual partners increased from 26.9 to 39.4% (P < 0.001), and the mean number of casual partners from eight (95% CI 8-8) to 11 (95% CI 10-11) (P = 0.05). Condomless anal sex with steady partner(s) remained stable over time (P = 0.5).

CONCLUSION

Among MSM in Amsterdam, incidence rates of HIV versus other STI show diverging trends. The increase in STI incidence coincides with a decrease in condom use with casual partners. The decrease in HIV incidence, despite increased sexual risk behavior, suggests that other HIV prevention methods have been successful in reducing HIV transmission among MSM.

Using HIV Risk Prediction Tools to Identify Candidates for Pre-Exposure Prophylaxis: Perspectives from Patients and Primary Care Providers

Clinical guidelines for HIV pre-exposure prophylaxis (PrEP) include risk prediction tools to identify appropriate candidates. We conducted a qualitative interview study to explore the potential acceptability, interpretation, and anticipated impact of such tools from the perspectives of men who have sex with men (MSM) and primary care providers (PCPs). Our purposive sample of English-speaking participants included: (1) MSM reporting HIV risk behaviors (n = 32; median age = 38 years; 53% non-Hispanic white; 22% high school degree or less education); (2) PCPs specializing in health care for MSM (n = 12); and (3) PCPs in general practice (n = 19). MSM participants questioned the ability of risk tools to predict HIV acquisition, and their perceptions of what might constitute a high HIV risk score varied widely. Many MSM participants believed that receiving a high score would prompt them to consider PrEP or other risk reduction strategies. Some believed that the data would be useful, particularly if discussed with their providers, whereas others anticipated feeling fear, anxiety, or mistrust. PCPs expressed more confidence in HIV risk prediction and imagined integrating tools with medical histories and their clinical judgment to assess risk. PCPs were most enthusiastic about adopting HIV risk prediction as a teaching tool to help patients visualize and reduce risk, their concerns about time constraints notwithstanding. In conclusion, our findings suggest that PCPs' views of HIV risk prediction tools are generally positive, whereas MSM participants' are more mixed. Given that both groups emphasized the value of contextualizing risk, shared decision making may be needed to implement HIV risk prediction tools effectively.

Impact of sexual trajectories of men who have sex with men on the reduction in HIV transmission by pre-exposure prophylaxis

Changes in sexual risk behavior over the life course in men who have sex with men (MSM) can influence population-level intervention efficacy. Our objective was to investigate the impact of incorporating sexual trajectories describing long-term changes in risk levels on the reduction in HIV prevalence by pre-exposure prophylaxis (PrEP) among MSM. Based on the Amsterdam Cohort Study data, we developed two models of HIV transmission in a population stratified by sexual behavior. In the first model, individuals were stratified into low, medium and high risk levels and did not change their risk levels. The second model had the same stratification but incorporated additionally three types of sexual behavior trajectories. The models assumed universal antiretroviral treatment of HIV⁺ MSM, and PrEP use by high risk HIV^- MSM. We computed the relative reduction in HIV prevalence in both models for annual PrEP uptakes of 10% to 80% at different time points after PrEP introduction. We then investigated the impact of sexual trajectories on the effectiveness of PrEP intervention. The impact of sexual trajectories on the overall prevalence and prevalence in individuals at low, medium and high risk levels varied with PrEP uptake and time after PrEP introduction. Compared to the model without sexual trajectories, the model with trajectories predicted a higher impact of PrEP on the overall prevalence, and on the prevalence among the medium and high risk individuals. In low risk individuals, there was more reduction in prevalence during the first 15 years of PrEP intervention if sexual trajectories were not incorporated in the model. After that point, at low risk level there was more reduction in the model with trajectories. In conclusion, our study predicts that sexual trajectories increase the estimated impact of PrEP on reducing HIV prevalence when compared to a population where risk levels do not change.