On-Demand Preexposure Prophylaxis in Men at High Risk for HIV-1 Infection

Humoral responses against HIV in male genital tract: role in sexual transmission and perspectives for preventive strategies

: Most new HIV infections occur via sexual routes. The induction of protective anti-HIV antibodies in genital mucosa is an important step toward reducing HIV transmission. Mucosal anti-HIV antibodies may play a dual role by either protecting against HIV transmission or facilitating it. Protective properties against HIV of mucosal IgGs and IgAs exhibiting neutralizing or antibody-dependent cell-mediated cytotoxicity activities have been described in highly exposed seronegative individuals. Conversely, some IgGs may facilitate the crossing of HIV free-particles through epithelial barriers by transcytosis. Hence knowledge of the mechanisms underlying anti-HIV antibody production in the genital tract and their exact role in sexual transmission may help to develop appropriate preventive strategies based on passive immunization or mucosal vaccination approaches. Our review focuses on the characteristics of the humoral immune responses against HIV in the male genital tract and related prevention strategies.

Preferences for Long-Acting Pre-exposure Prophylaxis (PrEP), Daily Oral PrEP, or Condoms for HIV Prevention Among U.S. Men Who Have Sex with Men

HIV prevention method preferences were evaluated among 512 U.S. men who have sex with men (MSM; median age: 22 years). Approximately 90 % consistently preferred one option across pairwise comparisons of condoms, daily oral pre-exposure prophylaxis (PrEP), and long-acting PrEP delivered via either an injectable or one of two types of PrEP implants differing in visibility. Condoms were most frequently preferred (33.8 %), followed by non-visible implants (21.5 %), and oral PrEP (17.0 %); HIV risk was reported by more choosing implants. In a follow-up question comparing the four PrEP options only, daily oral pills and non-visible implants were most frequently preferred (35.5 and 34.3 %, respectively), followed by injections (25.2 %) and visible implants (4.3 %). An inductive, open-coding approach determined that convenience, duration of protection, and privacy were the most commonly cited reasons for a PrEP method choice, and associated with self-report of HIV risk. Tailoring PrEP product development to privacy and other concerns important to those at highest HIV risk may improve HIV prevention.

Exploring Patterns of Awareness and Use of HIV Pre-Exposure Prophylaxis Among Young Men Who Have Sex with Men

Pre-exposure prophylaxis (PrEP) has shown promise as a safe and effective HIV prevention strategy, but there is limited research on awareness and use among young men who have sex with men (YMSM). Using baseline data from the "Keep It Up! 2.0" randomized control trial, we examined differences in PrEP awareness and use among racially diverse YMSM (N = 759; mean age = 24.2 years). Participants were recruited from study sites in Atlanta, Chicago, and New York City, as well as through national advertising on social media applications. While 67.5 % of participants reported awareness of PrEP, 8.7 % indicated using the medication. Awareness, but not use, varied by demographic variables. PrEP-users had twice as many condomless anal sex partners (ERR = 2.05) and more condomless anal sex acts (ERR = 1.60) than non-users. Future research should aim to improve PrEP awareness and uptake among YMSM and address condom use.

Awareness and Willingness to Use Pre-exposure Prophylaxis (PrEP) Among Men Who Have Sex with Men and Transgender Women in Brazil

Antiretroviral pre-exposure prophylaxis (PrEP) is recommended to prevent HIV infection among high-risk men who have sex with men (MSM) though not available in Brazil where the HIV epidemic persists unabated in this group. This cross-sectional study describes PrEP awareness and willingness and associated factors among MSM and transvestite/transgender women (trans women) pre-screened for the PrEP Brasil study. Awareness was reported by 61.3 % of the participants and was associated with age, education, site, study period and prior HIV testing. Most participants (82.1 %) were willing to use PrEP, which was associated with site, study period, number of male condomless anal sexual partners and anal sex with HIV positive/unknown partners. PrEP information is need among young and less educated individuals. Willingness to use PrEP was high and future studies should be conducted to confirm PrEP acceptability and the characteristics of the population who chose to adopt this intervention.

Optimizing Pre-Exposure Antiretroviral Prophylaxis Adherence in Men Who Have Sex with Men: Results of a Pilot Randomized Controlled Trial of "Life-Steps for PrEP"

Antiretroviral pre-exposure prophylaxis (PrEP) has been demonstrated to decrease HIV acquisition in multiple efficacy trials, but medication adherence is critical, and was suboptimal in several studies. Fifty HIV-uninfected at risk men who have sex with men (MSM) were randomized to a cognitive behavioral intervention condition or a time and session-matched comparison counseling intervention. The experimental intervention entailed four nurse-delivered initial and two booster sessions based on Life-Steps, an ART treatment adherence intervention. The comparison condition provided information and supportive counseling. The primary analyses compared adherence (Wisepill and tenofovir plasma levels) at 3 and 6 months. Fifty-eight MSM were screened to enroll 50 participants. Median age was 38.2 years old, 86% were white; 64% had completed college. Wisepill adherence was high in both groups, and not statistically different. Plasma tenofovir levels were significantly higher in the intervention group at 6 months using mean substitution analysis (i.e., computing missing variables) (p = 0.037), however, in the completer analyses (i.e., using only those completing all study visits), there were no statistically significant differences between randomization conditions. Medication adherence was high across a cognitive-behavioral (Life-Steps) and time-matched counseling intervention for PrEP adherence, with some evidence suggesting superiority of Life-Steps in this pilot RCT. Further evaluation in a fully powered efficacy trial is warranted to assess the robustness of this intervention.

Urine assay for tenofovir to monitor adherence in real time to tenofovir disoproxil fumarate/emtricitabine as pre-exposure prophylaxis

OBJECTIVES

Tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) is approved for pre-exposure prophylaxis (PrEP) against HIV infection. Adherence is critical for the success of PrEP, but current adherence measurements are inadequate for real-time adherence monitoring. We developed and validated a urine assay to measure tenofovir (TFV) to objectively monitor adherence to PrEP.

METHODS

We developed a urine assay using high-performance liquid chromatography coupled to tandem mass spectrometry with high sensitivity/specificity for TFV that allowed us to determine TFV concentrations in log₁₀ categories between 0 and 10 000 ng/mL. We validated the assay in three cohorts: (1) HIV-positive subjects with undetectable viral loads on a TDF/FTC-based regimen, (2) healthy HIV-negative subjects who received a single dose of TDF/FTC, and (3) HIV-negative subjects receiving daily TDF/FTC as PrEP for 24 weeks.

RESULTS

The urine assay detected TFV with greater sensitivity than plasma-based measures and with a window of measurements within 7 days of the last TDF/FTC dose. Based on the urine log-linear clearance after the last dose and its concordance with all detectable plasma levels, a urine TFV concentration > 1000 ng/mL was identified as highly predictive of the presence of TFV in plasma at > 10 ng/mL. The urine assay was able to distinguish high and low adherence patterns within the last 48 h (> 1000 ng/mL versus 10-1000 ng/mL), as well as nonadherence (< 10 ng/mL) extended over at least 1 week prior to measurement.

CONCLUSIONS

We provide proof of concept that a semiquantitative urine assay measuring levels of TFV could be further developed into a point-of-care test and be a useful tool to monitor adherence to PrEP.

Sexual transmission of HIV and the law: an Australian medical consensus statement

INTRODUCTION

Criminal cases involving human immunodeficiency virus transmission or exposure require that courts correctly comprehend the rapidly evolving science of HIV transmission and the impact of an HIV diagnosis. This consensus statement, written by leading HIV clinicians and scientists, provides current scientific evidence to facilitate just outcomes in Australian criminal cases involving HIV.Main recommendations: Caution should be exercised when considering charges or prosecutions regarding HIV transmission or exposure because:Scientific evidence shows that the risk of HIV transmission during sex between partners of different HIV serostatus can be low, negligible or too low to quantify, even when the HIV-positive partner is not taking effective antiretroviral therapy, depending on the nature of the sexual act, the viral load of the partner with HIV, and whether a condom or pre-exposure prophylaxis is employed to reduce risk.The use of phylogenetic analysis in cases of suspected HIV transmission requires careful consideration of its limited probative value as evidence of causation of HIV infection, although such an approach may provide valuable information, particularly in relation to excluding HIV transmission between individuals.Most people recently infected with HIV are able to commence simple treatment providing them a normal and healthy life expectancy, largely comparable with their HIV-negative peers. Among people who have been diagnosed and are receiving treatment, HIV is rarely life threatening. People with HIV can conceive children with negligible risk to their partner and low risk to their child.Changes in management as result of the consensus statement: Given the limited risk of HIV transmission per sexual act and the limited long term harms experienced by most people recently diagnosed with HIV, appropriate care should be taken before HIV prosecutions are pursued. Careful attention should be paid to the best scientific evidence on HIV risk and harms, with consideration given to alternatives to prosecution, including public health management.

High pre-exposure prophylaxis uptake and early adherence among men who have sex with men and transgender women at risk for HIV Infection: the PrEP Brasil demonstration project

INTRODUCTION

The efficacy of pre-exposure prophylaxis (PrEP) in preventing sexual acquisition of human immunodeficiency virus (HIV) is well established. Little is known about the feasibility of PrEP implementation in middle-income settings with concentrated epidemics among men who have sex with men (MSM) and transgender women (TGW).

METHODS

PrEP Brasil is a prospective, multicentre, open-label demonstration project assessing PrEP delivery in the context of the Brazilian Public Health System. HIV-uninfected MSM and TGW in 3 referral centres in Rio de Janeiro and São Paulo were evaluated for eligibility and offered 48 weeks of daily emtricitabine/tenofovir for PrEP. Concentrations of tenofovir diphosphate in dried blood spot samples (DBS) at week 4 after enrolment (early adherence) were measured. Predictors of drug levels were assessed using ordinal logistic regression models considering the DBS drug level as a 3 level variable (<350 fmol/punch, ≥350-699 fmol/punch and ≥700 fmol/punch).

RESULTS

1,270 individuals were assessed for participation; n = 738 were potentially eligible and n = 450 were offered PrEP (PrEP uptake was 60.9%). Eligible but not enrolled individuals were younger, had lower HIV risk perception and had lower PrEP awareness. At week 4, 424 participants (of the 450 enrolled) had DBS TFV-DP concentrations, 94.1% in the protective range (≥350 fmol/punch, consistent with ≥2 pills per week), and 78% were in the highly protective range (≥700 fmol/punch, ≥4 pills per week). Participants with ≥12 years of schooling had 1.9 times the odds (95%CI 1.10-3.29) of a higher versus lower drug level than participants with <12 years of schooling. Condomless receptive anal intercourse in the prior 3 months was also associated with higher drug levels (adjusted OR = 1.78; 95% CI 1.08-2.94).

CONCLUSION

The high uptake and early adherence indicate that PrEP for high-risk MSM and TGW can be successfully delivered in the context of the Brazilian Public Health System. Interventions to address disparities on PrEP awareness and HIV risk perception among the younger and less educated are urgently needed in order to maximize the impact of this prevention strategy on the reduction of HIV infection among MSM and TGW in Brazil.

The future of pre-exposure prophylaxis (PrEP) for human immunodeficiency virus (HIV) infection

INTRODUCTION

People at high risk for HIV acquisition should be offered pre-exposure prophylaxis (PrEP). Tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC) is currently the only medication recommended for pre-exposure prophylaxis (PrEP) by the Centers for Disease Control and Prevention (CDC) in people at high risk for HIV acquisition. This article will review medications currently under investigation and the future landscape of PrEP therapy. Areas covered: This article will review clinical trials that have investigated nontraditional regimens of TDF/FTC, antiretroviral agents from different drug classes such as integrase strand transfer inhibitors (INSTI), nucleoside reverse transcriptase inhibitors (NRTI), and non-nucleoside reverse transcriptase inhibitors (NNRTI) as potential PrEP therapies. Expert commentary: Currently, there are several investigational drugs in the pipeline for PrEP against HIV infection. Increased utilization of PrEP therapy depends on provider identification of people at high risk for HIV transmission. Advances in PrEP development will expand options and access for people and reduce the risk of HIV acquisition.

Differentiating Nonoccupational Postexposure Prophylaxis Seroconverters and Non-Seroconverters in a Community-Based Clinic in Los Angeles, California

BACKGROUND

Nonoccupational postexposure prophylaxis (nPEP) is a 28-day regimen of antiretroviral medications taken within 72 hours of human immunodeficiency virus (HIV) exposure to prevent HIV acquisition. Although nPEP has been recommended since 1998, few studies have analyzed the characteristics that distinguish nPEP failures (seroconverters) and successes (non-seroconverters).

METHODS

This retrospective study analyzed all nPEP courses prompted by sexual exposure that were prescribed at the Los Angeles LGBT Center between March 2010 and July 2014. Fisher exact tests and logistic regressions were used to determine characteristics that distinguished nPEP seroconverters from non-seroconverters.

RESULTS

Of the nPEP courses administered, 1744 had a follow-up visit for HIV testing within 24 weeks of exposure and 17 individuals seroconverted. Seven reported a known re-exposure, 8 self-reported only condom-protected sex subsequent to the initial exposure, and 2 reported abstinence since the exposure. In multivariable analyses, seroconverters were more likely than non-seroconverters to report methamphetamine use, incomplete medication adherence, and nPEP initiation later in the 72-hour window.

CONCLUSIONS

Nonoccupational postexposure prophylaxis is an important emergency tool for HIV prevention. Our findings corroborate that timing of the initial nPEP dose is an important predictor of seroconversion. Although the current study did not offer the initial nPEP dose at the beginning of the visit, use of this fast-track dosing schedule will ensure that the first dose is taken as early as possible postexposure and may lower the likelihood for seroconversion. Furthermore, we recommend systematic screening for substance use because these individuals may be well suited for pre-exposure prophylaxis given their sustained risk.

Community acceptance and HIV sexual risk among gay and bisexual men in a ‘typical’ Canadian city

Included in Statistics Canada's largest geographical “peer group,” London, Ontario is typical of many mid-size Canadian cities. A local health forum identified community acceptance and homophobia as key factors impacting LGBTQ health; we studied these with regard to HIV-related sexual risk in gay and bisexual men. Survey data were collected from 201 gay and bisexual men in Middlesex-London, Ontario; 173 reported their HIV status as negative/unknown and were included in this analysis. Unadjusted and adjusted prevalence risk ratios (PRRs) were modelled using modified Poisson regression. First, a model was fit for non-modifiable sociodemographic and background factors. Community factors were then added: social support; internalized homonegativity; perceptions of community acceptance of people like oneself (based on orientation, racialization, gender identity). Older age was associated with decreased risk; other sociodemographic and background factors were not. For each 10-year increase in age, prevalence of high-risk sex decreased by 24% (PRR=0.76; 95% CI: 0.60, 0.95). Controlling for age, we found an interaction between perception of broader community acceptance and gay community acceptance of people like oneself. As broader community acceptance increased, high-risk sex decreased; however, this effect varied depending upon perceptions of gay community acceptance, with men feeling most accepted within the gay community having the smallest reductions in high-risk sex. This interaction raises a series of questions. Among these: How do community norms and availability of partners shape sexual risk-taking? Are conventional “contextualized” measures of sexual risk sufficient, or do they miss important risk-mitigation strategies used within gay communities?

Correlates of willingness to initiate pre-exposure prophylaxis and anticipation of practicing safer drug- and sex-related behaviors among high-risk drug users on methadone treatment

BACKGROUND

Although people who use drugs (PWUD) are key populations recommended to receive pre-exposure prophylaxis (PrEP) to prevent HIV, few data are available to guide PrEP delivery in this underserved group. We therefore examined the willingness to initiate PrEP and the anticipation of HIV risk reduction while on PrEP among high-risk PWUD.

METHODS

In a cross-sectional study of 400 HIV-negative, opioid dependent persons enrolled in a methadone program and reporting recent risk behaviors, we examined independent correlates of being willing to initiate PrEP.

RESULTS

While only 72 (18%) were aware of PrEP, after being given a description of it, 251 (62.7%) were willing to initiate PrEP. This outcome was associated with having neurocognitive impairment (aOR=3.184, p=0.004) and higher perceived HIV risk (aOR=8.044, p<0.001). Among those willing to initiate PrEP, only 12.5% and 28.2%, respectively, indicated that they would always use condoms and not share injection equipment while on PrEP. Consistent condom use was associated with higher income (aOR=8.315, p=0.016), always using condoms with casual partners (aOR=6.597, p=0.001), and inversely associated with ongoing drug injection (aOR=0.323, p=0.027). Consistent safe injection, however, was inversely associated with age (aOR=0.948, p=0.035), ongoing drug injection (aOR=0.342, p<0.001), and perceived HIV risk (aOR=0.191, p=0.019).

CONCLUSIONS

While willingness to initiate PrEP was high and correlated with being at elevated risk for HIV, anticipated higher risk behaviors in this group even while on PrEP suggests that the next generation of HIV prevention approaches may need to combine biomedical and behavioral components to sustain HIV risk reduction over time.

Prevention Strategies Against HIV Transmission: A Proactive Approach

Human immunodeficiency virus (HIV) has now transformed into a manageable chronic condition. Highly active antiretroviral therapy (HAART) has proven efficacious at controlling the disease progression. Based on compelling evidence, the Department of Health and Human Services (DHHS) and the Infectious Disease Society of America (IDSA) developed guidelines for the management of persons infected with HIV. However, there are approximately 50 000 new cases of HIV in the United States each year. In this article, we review proactive methods to reduce the transmission of HIV, which include reinforcing patient education, gel-coated condoms that destroy HIV, HIV vaccinations, and adequately utilizing pre-exposure prophylaxis (PrEP), and post-exposure prophylaxis (PEP). Further development and consistent utilization of innovative prevention tools can significantly reduce the incidence of HIV infections regardless of HIV status.

Usability and Acceptability of a Mobile Comprehensive HIV Prevention App for Men Who Have Sex With Men: A Pilot Study

BACKGROUND

Men who have sex with men (MSM) are the group most impacted by the human immunodeficiency virus (HIV) epidemic and the only subgroup in the United States among which new HIV diagnoses are not decreasing. To achieve the US National HIV/AIDS (acquired immunodeficiency syndrome) Strategy goals of reducing new diagnoses by 25%, high (eg, 30-50%) coverage of multiple HIV prevention interventions is needed in both urban and rural areas. Mobile phone "apps" are an important channel through which prevention services could be provided at scale and at low marginal cost.

OBJECTIVE

The aim of this study was to evaluate the usability and acceptability of a theory-based Android mobile phone app for HIV prevention.

METHODS

The app included self-assessment tools; prevention recommendations; commodity (condoms, HIV self-tests) ordering; reminders to MSM for basic HIV prevention services, HIV testing, condom use, screening for preexposure prophylaxis (PrEP) and nonoccupational postexposure prophylaxis (nPEP); and prevention and treatment provider locators. The study recruited HIV-negative, Android-using MSM in Atlanta and Seattle who were asked to use the app for 4 months and complete a post-use survey. We measured the use of the app and its features, ordering of commodities, self-report of establishing an HIV testing plan, being HIV tested in the community, and starting PrEP or using nPEP. Usability was assessed using the system usability scale (SUS).

RESULTS

A total of 121 MSM were enrolled (59.5%, 72/121 from Atlanta; 40.5%, 49/121 from Seattle). Median age was 28. Nearly half (48.8%, 59/121) were nonwhite, and most (85.9%, 104/121) were gay-identified. Most had tested for HIV in the past (85.1%, 103/121), and 52 (43.0%, 52/121) had a plan to test for HIV regularly. Men used the app for an average of 17.7 minutes over the first 4 months. Over the 4-month period, over half ordered condoms (63.6%, 77/121) and HIV test kits (52.8%, 64/121) on the app. Eight of 86 (9%) PrEP-eligible MSM started PrEP during the 4-month period; of those, 6 of the 8 reported that the app influenced their decision to start PrEP. The mean SUS was 73 (above average).

CONCLUSIONS

A theory-based mobile phone app was acceptable to MSM and was rated as having above-average usability. Most men used the commodity-ordering features of the app during the 4-month evaluation period, and nearly 1 in 10 PrEP-eligible men started PrEP, with most attributing their decision to start PrEP in part to the app. A broader, randomized controlled study of the impact of the app on uptake of prevention behaviors for MSM is warranted.

Awareness and attitudes of pre-exposure prophylaxis for HIV prevention among physicians in Guatemala: Implications for country-wide implementation

INTRODUCTION

HIV continues to be a major health concern with approximately 2.1 million new infections occurring worldwide in 2015. In Central America, Guatemala had the highest incident number of HIV infections (3,700) in 2015. Antiretroviral pre-exposure prophylaxis (PrEP) was recently recommended by the World Health Organization (WHO) as an efficacious intervention to prevent HIV transmission. PrEP implementation efforts are underway in Guatemala and success will require providers that are knowledgeable and willing to prescribe PrEP. We sought to explore current PrEP awareness and prescribing attitudes among Guatemalan physicians in order to inform future PrEP implementation efforts.

METHODS

We conducted a cross-sectional survey of adult internal medicine physicians at the main teaching hospital in Guatemala City in March 2015. The survey included demographics, medical specialty, years of HIV patient care, PrEP awareness, willingness to prescribe PrEP, previous experience with post-exposure prophylaxis, and concerns about PrEP. The primary outcome was willingness to prescribe PrEP, which was assessed using a 5-point Likert scale for different at-risk population scenarios. Univariate and multivariate logistic regression was performed to identify predictors for willingness to prescribe PrEP.

RESULTS

Eighty-seven physicians completed the survey; 66% were male, 64% were internal medicine residency trainees, and 10% were infectious disease (ID) specialists. Sixty-nine percent of physicians were PrEP aware, of which 9% had previously prescribed PrEP. Most (87%) of respondents were willing to prescribe PrEP to men who have sex with men (MSM), sex workers, injection drug users, or HIV-uninfected persons having known HIV-positive sexual partners. Concerns regarding PrEP included development of resistance (92%), risk compensation (90%), and cost (64%). Univariate logistic regression showed that younger age, being a resident trainee, and being a non-ID specialist were significant predictors for willingness to prescribe PrEP. In multivariate logistic regression, being a non-ID specialist was a significant predictor.

CONCLUSIONS

Guatemalan physicians at an urban public hospital were PrEP aware and willing to prescribe, but few have actually done so yet. Future education programs should address the concerns identified, including the low potential for the development of antiretroviral resistance. These findings can aid PrEP implementation efforts in Guatemala.

MTN-017: A Rectal Phase 2 Extended Safety and Acceptability Study of Tenofovir Reduced-Glycerin 1% Gel

Background

Human immunodeficiency virus (HIV) disproportionately affects men who have sex with men (MSM) and transgender women (TGW). Safe and acceptable topical HIV prevention methods that target the rectum are needed.

Methods

MTN-017 was a phase 2, 3-period, randomized sequence, open-label, expanded safety and acceptability crossover study comparing rectally applied reduced-glycerin (RG) 1% tenofovir (TFV) and oral emtricitabine/TFV disoproxil fumarate (FTC/TDF). In each 8-week study period participants were randomized to RG-TFV rectal gel daily, or RG-TFV rectal gel before and after receptive anal intercourse (RAI; or at least twice weekly in the event of no RAI), or daily oral FTC/TDF.

Results

MSM and TGW (n = 195) were enrolled from 8 sites in the United States, Thailand, Peru, and South Africa with mean age of 31.1 years (range 18-64). There were no differences in ≥grade 2 adverse event rates between daily gel (incidence rate ratio [IRR], 1.09; P = .59) or RAI gel (IRR, 0.90; P = .51) compared to FTC/TDF. High adherence (≥80% of prescribed doses assessed by unused product return and Short Message System reports) was less likely in the daily gel regimen (odds ratio [OR], 0.35; P < .001), and participants reported less likelihood of future daily gel use for HIV protection compared to FTC/TDF (OR, 0.38; P < .001).

Conclusions

Rectal application of RG TFV gel was safe in MSM and TGW. Adherence and product use likelihood were similar for the intermittent gel and daily oral FTC/TDF regimens, but lower for the daily gel regimen.

Clinical Trials Registration

NCT01687218.

Executive summary: Pre-exposure prophylaxis for prevention of HIV infection in adults in Spain: July 2016

Administration of antiretroviral drugs to individuals exposed to, but not infected by, HIV has been shown to reduce the risk of transmission. The efficacy of pre-exposure prophylaxis (PrEP) makes it obligatory to include it in an integral program of prevention of HIV transmission, together with other measures, such as use of the condom, training, counseling, and appropriate treatment of infected individuals. In this document, the AIDS Study Group (GeSIDA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica [SEIMC]) provides its views on this important subject. The available evidence on the usefulness of PrEP in the prevention of transmission of HIV is presented, and the components that should make up a PrEP program and whose development and implementation are feasible in Spain are set out.

Spatiotemporal dynamics of HIV-1 transmission in France (1999-2014) and impact of targeted prevention strategies

Background

Characterizing HIV-1 transmission networks can be important in understanding the evolutionary patterns and geospatial spread of the epidemic. We reconstructed the broad molecular epidemiology of HIV from individuals with primary HIV-1 infection (PHI) enrolled in France in the ANRS PRIMO C06 cohort over 15 years.

Results

Sociodemographic, geographic, clinical, biological and pol sequence data from 1356 patients were collected between 1999 and 2014. Network analysis was performed to infer genetic relationships, i.e. clusters of transmission, between HIV-1 sequences. Bayesian coalescent-based methods were used to examine the temporal and spatial dynamics of identified clusters from different regions in France. We also evaluated the use of network information to target prevention efforts. Participants were mostly Caucasian (85.9%) and men (86.7%) who reported sex with men (MSM, 71.4%). Overall, 387 individuals (28.5%) were involved in clusters: 156 patients (11.5%) in 78 dyads and 231 participants (17%) in 42 larger clusters (median size: 4, range 3–41). Compared to individuals with single PHI (n = 969), those in clusters were more frequently men (95.9 vs 83%, p < 0.01), MSM (85.8 vs 65.6%, p < 0.01) and infected with CRF02_AG (20.4 vs 13.4%, p < 0.01). Reconstruction of viral migrations across time suggests that Paris area was the major hub of dissemination of both subtype B and CRF02_AG epidemics. By targeting clustering individuals belonging to the identified active transmission network before 2010, 60 of the 143 onward transmissions could have been prevented.

Conclusion

These analyses support the hypothesis of a recent and rapid rise of CRF02_AG within the French HIV-1 epidemic among MSM. Combined with a short turnaround time for sample processing, targeting prevention efforts based on phylogenetic monitoring may be an efficient way to deliver prevention interventions but would require near real time targeted interventions on the identified index cases and their partners.

Electronic supplementary material

The online version of this article (doi:10.1186/s12977-017-0339-4) contains supplementary material, which is available to authorized users.

Social, structural, behavioral and clinical factors influencing retention in Pre-Exposure Prophylaxis (PrEP) care in Mississippi

Pre-exposure prophylaxis (PrEP) is a biomedical intervention that can reduce rates of HIV transmission when taken once daily by HIV-negative individuals. Little is understood about PrEP uptake and retention in care among the populations most heavily impacted by the HIV epidemic, particularly among young men who have sex with men (YMSM) in the Deep South. Therefore, this study explored the structural, social, behavioral, and clinical factors that affect PrEP use and retention in care among YMSM in Jackson, Mississippi. Thirty MSM who were prescribed PrEP at an outpatient primary care clinic were interviewed and included 23 men who had been retained in PrEP care and seven who had not been retained. The mean age of participants was 26.6 years. Most (23) participants were African American. Major factors affecting PrEP use and retention in PrEP care included 1) structural factors such as cost and access to financial assistance for medications and clinical services; 2) social factors such as stigma and relationship status; 3) behavioral factors including sexual risk behaviors; and 4) clinical factors such as perceived and actual side effects. Many participants also discussed the positive spillover effects of PrEP use and reported that PrEP had a positive impact on their health. Four of the seven individuals who had not been retained re-enrolled in PrEP care after completing their interviews, suggesting that case management and ongoing outreach can enhance retention in PrEP care. Interventions to enhance retention in PrEP care among MSM in the Deep South will be most effective if they address the complex structural, social, clinical, and behavioral factors that influence PrEP uptake and retention in PrEP care.

Tenofovir alafenamide and elvitegravir loaded nanoparticles for long-acting prevention of HIV-1 vaginal transmission

OBJECTIVE

This report presents tenofovir (TFV) alafenamide (TAF) and elvitegravir (EVG) fabricated into nanoparticles for subcutaneous delivery as prevention strategy.

DESIGN

Prospective prevention study in humanized bone marrow-liver-thymus (hu-BLT) mice.

METHODS

Using an oil-in-water emulsion solvent evaporation technique, TAF + EVG drugs were entrapped together into nanoparticles containing poly(lactic-co-glycolic acid). In-vitro prophylaxis studies (90% inhibition concentration) compared nanoparticles with drugs in solution. Hu-BLT (n = 5/group) mice were given 200 mg/kg subcutaneous, and vaginally challenged with HIV-1 [5 × 10 tissue culture infectious dose for 50% of cells cultures (TCID50)] 4 and 14 days post-nanoparticle administration (post-nanoparticle injection). Control mice (n = 5) were challenged at 4 days. Weekly plasma viral load was performed using RT-PCR. Hu-BLT mice were sacrificed and lymph nodes were harvested for HIV-1 viral RNA detection by in-situ hybridization. In parallel, CD34 humanized mice (3/time point) compared TFV and EVG drug levels in vaginal tissues from nanoparticles and solution. TFV and EVG were analyzed from tissue using liquid chromatograph-tandem mass spectrometry (LC-MS/MS).

RESULTS

TAF + EVG nanoparticles were less than 200 nm in size. In-vitro prophylaxis indicates TAF + EVG nanoparticles 90% inhibition concentration was 0.002 μg/ml and TAF + EVG solution was 0.78 μg/ml. TAF + EVG nanoparticles demonstrated detectable drugs for 14 days and 72 h for solution, respectively. All hu-BLT control mice became infected within 14 days after HIV-1 challenge. In contrast, hu-BLT mice that received nanoparticles and challenged at 4 days post-nanoparticle injection, 100% were uninfected, and 60% challenged at 14 days post-nanoparticle injection were uninfected (P = 0.007; Mantel-Cox test). In-situ hybridization confirmed these results.

CONCLUSION

This proof-of-concept study demonstrated sustained protection for TAF + EVG nanoparticles in a hu-BLT mouse model of HIV vaginal transmission.

Poly drug use, chemsex drug use, and associations with sexual risk behaviour in HIV-negative men who have sex with men attending sexual health clinics

BACKGROUND

Recreational drug use and associated harms continue to be of significant concern in men who have sex with men (MSM) particularly in the context of HIV and STI transmission.

METHODS

Data from 1484 HIV-negative or undiagnosed MSM included in the AURAH study, a cross-sectional, self-completed questionnaire study of 2630 individuals from 20 sexual health clinics in the United Kingdom in 2013-2014, was analysed. Two measures of recreational drug use in the previous three months were defined; (i) polydrug use (use of 3 or more recreational drugs) and (ii) chemsex drug use (use of mephedrone, crystal methamphetamine or GHB/GBL). Associations of socio-demographic, health and lifestyle factors with drug use, and associations of drug use with sexual behaviour, were investigated.

RESULTS

Of the 1484 MSM, 350 (23.6%) reported polydrug use and 324 (21.8%) reported chemsex drug use in the past three months. Overall 852 (57.5%) men reported condomless sex in the past three months; 430 (29.0%) had CLS with ≥2 partners, 474 (31.9%) had CLS with unknown/HIV+ partner(s); 187 (12.6%) had receptive CLS with an unknown status partner. For polydrug use, prevalence ratios (95% confidence interval) for association with CLS measures, adjusted for socio-demographic factors were: 1.38 (1.26, 1.51) for CLS; 2.11 (1.80, 2.47) for CLS with ≥2 partners; 1.89 (1.63, 2.19) for CLS with unknown/HIV+ partner(s); 1.36 (1.00, 1.83) for receptive CLS with an unknown status partner. Corresponding adjusted prevalence ratios for chemsex drug use were: 1.38 (1.26, 1.52); 2.07 (1.76, 2.43); 1.88 (1.62, 2.19); 1.49 (1.10, 2.02). Polydrug and chemsex drug use were also strongly associated with previous STI, PEP use, group sex and high number of new sexual partners. Associations remained with little attenuation after further adjustment for depressive symptoms and alcohol intake.

CONCLUSION

There was a high prevalence of polydrug use and chemsex drug use among HIV negative MSM attending UK sexual health clinics. Drug use was strongly associated with sexual behaviours linked to risk of acquisition of STIs and HIV.

Generational analysis of trends in unprotected sex in France among men who have sex with men: The major role of context-driven evolving patterns

OBJECTIVE

Using a generational approach, this study analyses how unprotected anal intercourse has evolved since 1991 in France across different generations of men who have sex with men (MSM) whose sexual lives began at different periods in the history of the HIV epidemic.

DESIGN

Data were collected from 18-59 year-old respondents to the French Gay Press surveys Enquêtes Presse Gay, conducted repeatedly between 1991 and 2011 (N = 32,196) using self-administered questionnaires distributed in gay magazines and over the internet.

METHODS

Trends in unprotected anal intercourse (i.e. condomless anal sex) with casual partners of unknown or different HIV serostatus (hereafter "UAId" in this manuscript) were studied. Responses were analysed according to year and then reorganised for age-cohort analyses by generation, based on the year respondents turned 18.

RESULTS

UAId rates fell from 1991 to 1997, and then rose from 13.4% in 1997 to 25.5% in 2011 among seronegative respondents, and from 24.8% to 63.3%, respectively, among seropositive respondents. Both in seropositive and seronegative respondents, UAId increased over time for all generations, indicative of a strong period effect.

CONCLUSION

Analyses of data from several generations of MSM who started their sexual lives at different time points in the HIV epidemic, revealed very similar trends in UAId between generations, among both seropositive and seronegative respondents. This strong period effect suggests that sexual behaviours in MSM are influenced more by contextual than generational factors. The fact that prevention practices are simultaneously observed in different generations and that there are most likely underlying prevention norms among MSM, suggests that PrEP could become widely accepted by all generations of MSM exposed to the risk of HIV.

HIV Pre-Exposure Prophylaxis and Postexposure Prophylaxis in Japan: Context of Use and Directions for Future Research and Action

Biomedical HIV prevention strategies are playing an increasingly prominent role in addressing HIV epidemics globally, but little is known about their use in Japan, where persistent HIV disparities and a recently stable, but not declining, national epidemic indicate the need for evolving approaches. We conducted an ethnographic study to determine the context of pre-exposure prophylaxis (PrEP) and postexposure prophylaxis (PEP) use and to identify directions for future research and action in Japan. We used data from observational fieldwork in the Kansai region and Tokyo Metropolitan Area (n = 178 persons observed), qualitative interviews (n = 32), documents and web-based data sources (n = 321), and email correspondences (n = 9) in the period 2013-2016. Drug approvals by Japan's regulatory agencies, insurance coverage for medications, and policies by healthcare institutions and government agencies were the main factors affecting PrEP and PEP legality, use, and awareness. Awareness and the observable presence of PrEP and PEP were very limited, particularly at the community level. PrEP and PEP held appeal for Japanese scientists and activists, and for study participants who represented various other stakeholder groups; however, significant concerns prevented open endorsements. Japanese health officials should prioritize a national discussion, weigh empirical evidence, and strongly consider formal approval of antiretroviral (ARV) medications for use in PrEP and both occupational and nonoccupational PEP. Once approved, social marketing campaigns can be used to advertise widely and increase awareness. Future research would benefit from theoretical grounding in a diffusion of innovations framework. These findings can inform current and future ARV-based prevention strategies at a critical time in the international conversation.

Pre-Exposure Prophylaxis: A Narrative Review of Provider Behavior and Interventions to Increase PrEP Implementation in Primary Care

Since FDA approval of HIV pre-exposure prophylaxis (PrEP) for HIV prevention, attention has been focused on PrEP implementation. The CDC estimates that 1.2 million U.S. adults might benefit from PrEP, but only a minority are using PrEP, so there is a significant unmet need to increase access for those at risk for HIV. Given the large numbers of individuals who have indications for PrEP, there are not enough practicing specialists to meet the growing need for providers trained in providing PrEP. Moreover, since PrEP is a preventive intervention for otherwise healthy individuals, primary care providers (PCPs) should be primary prescribers of PrEP. There are important clinical considerations that providers should take into account when planning to prescribe PrEP, which are highlighted in the clinical case discussed. A growing body of research also suggests that some providers may be cautious about prescribing PrEP because of concerns regarding its "real-world" effectiveness, anticipated unintended consequences associated with its use, and ambiguity as to who should prescribe it. This review summarizes findings from studies that have assessed prescriber behavior regarding provision of PrEP, and offers recommendations on how to optimize PrEP implementation in primary care settings. Development and dissemination of educational interventions for PCPs and potential PrEP users are needed, including improved methods to assist clinicians in identifying appropriate PrEP candidates, and programs to promote medication adherence and access to social and behavioral health services. PCPs are well-positioned to prescribe PrEP and coordinate health-related services to improve the sexual health of their patients, but tailored educational programs are needed.

Pre-Exposure Prophylaxis (PrEP) as an Additional Tool for HIV Prevention Among Men Who Have Sex With Men in Belgium: The Be-PrEP-ared Study Protocol

Background

Pre-exposure prophylaxis (PrEP) is a promising and effective tool to prevent HIV. With the approval of Truvada as daily PrEP by the European Commission in August 2016, individual European Member states prepare themselves for PrEP implementation following the examples of France and Norway. However, context-specific data to guide optimal implementation is currently lacking.

Objective

With this demonstration project we evaluate whether daily and event-driven PrEP, provided within a comprehensive prevention package, is a feasible and acceptable additional prevention tool for men who have sex with men (MSM) at high risk of acquiring HIV in Belgium. The study’s primary objective is to document the uptake, acceptability, and adherence to both daily and event-driven PrEP, while several secondary objectives have been formulated including impact of PrEP use on sexual behavior.

Methods

The Be-PrEP-ared study is a phase 3, single-site, open-label prospective cohort study with a large social science component embedded in the trial. A total of 200 participants choose between daily or event-driven PrEP use and may switch, discontinue, or restart their regimen at the 3-monthly visits for a duration of 18 months. Data are collected on several platforms: an electronic case report form, a Web-based tool where participants register their sexual behavior and pill use, a more detailed electronic self-administered questionnaire completed during study visits on a tablet computer, and in-depth interviews among a selected sample of participants. To answer the primary objective, the recruitment rate, (un)safe sex behavior during the last 6 months, percentage of reported intention to use PrEP in the future, retention rates in different regimens, and attitudes towards PrEP use will be analyzed. Adherence will be monitored using self-reported adherence, pill count, tenofovir drug levels in blood samples, and the perceived skills to adhere.

Results

All participants are currently enrolled, and the last study visit is planned to take place around Q3 2018.

Conclusions

As PrEP is not yet available in Belgium for use, this study will provide insights into how to optimally implement PrEP within the current health care provision and will shape national and European guidelines with regard to the place of PrEP in HIV prevention strategies.

ClinicalTrial

EU Clinical Trial 2015-000054-37; https://www.clinicaltrialsregister.eu/ctr-search/trial/2015-000054-37/BE (Archived by WebCite at http://www.webcitation.org/6nacjSdmM).

Significant publications on infectious diseases pharmacotherapy in 2015

PURPOSE

The most important articles on infectious diseases (ID) pharmacotherapy published in the peer-reviewed literature in 2015, as nominated and selected by panels of pharmacists and others with ID expertise, are summarized.

SUMMARY

Members of the Houston Infectious Diseases Network were asked to nominate articles published in prominent peer-reviewed journals in 2015 that were thought to have a major impact in the field of ID pharmacotherapy. A list of 55 nominated articles on general ID-related topics and 10 articles specifically related to human immunodeficiency virus (HIV) infection or acquired immunodeficiency syndrome (AIDS) was compiled. In a national online survey, members of the Society of Infectious Diseases Pharmacists (SIDP) were asked to select from the list 10 general ID articles believed to have made a significant contribution to the field of ID pharmacotherapy and 1 article contributing to HIV/AIDS pharmacotherapy. Of the 361 SIDP members surveyed, 153 (42%) and 76 (21%) participated in the selection of general ID-related articles and HIV/AIDS-related articles, respectively. The 11 highest-ranked publications (10 general ID-related articles and 1 HIV/AIDS-related article) are summarized here.

CONCLUSION

With the growing number of significant ID-related publications each year, it can be challenging to stay current with the literature. This review of important ID pharmacotherapy publications in 2015 may be helpful in identifying key articles and lessening this burden.

Epidemiological Profile of Newly Diagnosed HIV-Infected Patients in Northern Paris: A Retrospective Study

In attempt to identify the factors associated with delayed diagnosis during HIV infection, we studied retrospectively the epidemiological profile of HIV-infected patients diagnosed between January 1, 2012 and December 31, 2013 and followed in our clinical center in Paris. Data were compared to those obtained at the same site during the year 2003. One hundred eighty-six patients fulfilled the inclusion criteria: 49 (26%) had a CD4 count <200/mm³ at diagnosis. Compared to subjects with CD4 count ≥200/mm³, advanced patients were older, had a higher plasma viral load, had more often an AIDS-defining event at the time of HIV diagnosis (45% vs. 3%), had been infected more often through heterosexual contact (69% vs. 44%), had less frequently past HIV testing (23% vs. 63%), and tended to live in less favorable conditions. A higher proportion of these patients initiated antiretroviral therapy in the 3 months following diagnosis (93.9% vs. 48.1%). Compared to data obtained in 161 patients in 2003, the proportions of advanced patients were similar between the two periods (26% vs. 22%). There was a significant increase from year 2003 to the 2012-2013 period in the proportion of men who have sex with men (MSM) (50% vs. 27%) and in the percentage of patients infected with HIV-1 subtype B (48% vs. 27%) and with positive syphilis serology (22% vs. 8%). Our data show that (1) HIV screening should be extended to populations with the following characteristics: older age, heterosexuality, and low socioeconomic level, and (2) HIV transmission continues to progress in MSM, arguing for the value of preexposure prophylaxis.

Global travel and HIV/STI epidemics among MSM: what does the future hold?

Infectious disease epidemics occur within dynamic systems and environments that shape risk and, ultimately, the spread of infectious diseases. Gay men and other men who have sex with men (MSM) are disproportionately impacted by HIV everywhere in the world. Several emerging trends present risks for sustained or increased HIV acquisition and transmission, and the growth of global travel in the context of emerging online platforms for social/sexual networking is discussed here. Four factors associated with travel that could potentiate HIV transmission are highlighted: different patterns of sexual risk behaviours during travel; the growth of online tools to meet sex partners more efficiently; the global heterogeneity of HIV strains; and the potential for diassortative mixing of men from high- and low-HIV prevalence areas. Prevention tools and services must rise to these challenges, and innovative mobile applications and programs have played, and will continue to play, an important role in supporting MSM at risk for or living with HIV during their periods of travel.

Basis and Statistical Design of the Passive HIV-1 Antibody Mediated Prevention (AMP) Test-of-Concept Efficacy Trials

BACKGROUND

Anti-HIV-1 broadly neutralizing antibodies (bnAbs) have been developed as potential agents for prevention of HIV-1 infection. The HIV Vaccine Trials Network and the HIV Prevention Trials Network are conducting the Antibody Mediated Prevention (AMP) trials to assess whether, and how, intravenous infusion of the anti-CD4 binding site bnAb, VRC01, prevents HIV-1 infection. These are the first test-of-concept studies to assess HIV-1 bnAb prevention efficacy in humans.

METHODS

The AMP trials are two parallel phase 2b HIV-1 prevention efficacy trials conducted in two cohorts: 2700 HIV-uninfected men and transgender persons who have sex with men in the United States, Peru, Brazil, and Switzerland; and 1500 HIV-uninfected sexually active women in seven countries in sub-Saharan Africa. Participants are randomized 1:1:1 to receive an intravenous infusion of 10 mg/kg VRC01, 30 mg/kg VRC01, or a control preparation every 8 weeks for a total of 10 infusions. Each trial is designed (1) to assess overall prevention efficacy (PE) pooled over the two VRC01 dose groups vs. control and (2) to assess VRC01 dose and laboratory markers as correlates of protection (CoPs) against overall and genotype- and phenotype-specific infection.

RESULTS

Each AMP trial is designed to have 90% power to detect PE > 0% if PE is ≥ 60%. The AMP trials are also designed to identify VRC01 properties (i.e., concentration and effector functions) that correlate with protection and to provide insight into mechanistic CoPs. CoPs are assessed using data from breakthrough HIV-1 infections, including genetic sequences and sensitivities to VRC01-mediated neutralization and Fc effector functions.

CONCLUSIONS

The AMP trials test whether VRC01 can prevent HIV-1 infection in two study populations. If affirmative, they will provide information for estimating the optimal dosage of VRC01 (or subsequent derivatives) and identify threshold levels of neutralization and Fc effector functions associated with high-level protection, setting a benchmark for future vaccine evaluation and constituting a bridge to other bnAb approaches for HIV-1 prevention.

Limited HIV-1 Reactivation in Resting CD4+ T cells from Aviremic Patients under Protease Inhibitors

A latent viral reservoir that resides in resting CD4⁺ T cells represents a major barrier for eradication of HIV infection. We test here the impact of HIV protease inhibitor (PI) based combination anti-retroviral therapy (cART) over nonnucleoside reverse transcriptase inhibitor (NNRTI)-based cART on HIV-1 reactivation and integration in resting CD4⁺ T cells. This is a prospective cohort study of patients with chronic HIV-1 infection treated with conventional cART with an undetectable viremia. We performed a seven-year study of 47 patients with chronic HIV-infection treated with cART regimens and with undetectable plasma HIV-1 RNA levels for at least 1 year. Of these 47 patients treated with cART, 24 were treated with a PI-based regimen and 23 with a NNRTI-based regimen as their most recent treatment for more than one year. We evaluated the HIV-1 reservoir using reactivation assay and integrated HIV-1 DNA, respectively, in resting CD4⁺ T cells. Resting CD4⁺ T cells isolated from PI-treated patients compared to NNRTI-treated patients showed a limited HIV-1 reactivation upon T-cell stimulation (p = 0·024) and a lower level of HIV-1 integration (p = 0·024). Our study indicates that PI-based cART could be more efficient than NNRTI-based cART for limiting HIV-1 reactivation in aviremic chronically infected patients.

Post-exposure prophylaxis awareness and use among men who have sex with men in London who use geosocial-networking smartphone applications

The number of new HIV infections continues to be on the rise in many high-income countries, most notably among men who have sex with men (MSM). Despite recent attention to the use of antiretroviral medications as pre-exposure prophylaxis (PrEP) among MSM, considerably less research has been devoted to examining the awareness and use of post-exposure prophylaxis (PEP). Based on a convenience sample of 179 self-reported HIV-uninfected MSM using a geosocial-networking smartphone application, this study is among the first to examine the awareness and use of PEP and their demographic and behavioral correlates among MSM in London. Most respondents (88.3%) had heard of PEP, where 27.4% reported having used it. In multivariable models, the disclosure of one's sexual orientation to their general practitioner (Prevalence ratio [PR]: 3.49; 95% confidence interval (CI): 1.14, 10.70; p = .029) and reporting one's HIV status as negative (rather than unknown) (PR: 11.49; 95% CI: 1.68, 76.92; p = .013) were associated with having heard of PEP; while the recent use of club drugs (PR: 3.02; 95% CI: 1.42, 6.43; p = .004) was associated with having ever used PEP. High awareness and use in this sample suggest that PEP is a valuable risk-reduction strategy that should be capitalized on, be it in addition to or in the absence of PrEP.

Pre-exposure Prophylaxis (PrEP) Use, Seroadaptation, and Sexual Behavior Among Men Who Have Sex with Men, San Francisco, 2004-2014

The Food and Drug Administration approved pre-exposure prophylaxis (PrEP) to prevent HIV infection, and the Centers for Disease Control and Prevention has presented PrEP as a prevention option for groups at high risk such as men who have sex with men (MSM). Intervention data provide some information on how PrEP affects sexual behavior of MSM in trials, open label extensions, or clinics. However, it is unclear whether sexual risk and preventive behavioral patterns are changing in the population as a whole as PrEP becomes more widely available, whether due to PrEP use or other factors. We examined trends in PrEP use, numbers of condomless anal sex partners, consistent condom use, and seroadaptive strategies in San Francisco-a city which has actively promoted PrEP-using data from National HIV Behavioral Surveillance (NHBS). NHBS recruited 1211, 383, 373, and 268 HIV-negative MSM in 2004, 2008, 2011, and 2014, respectively. PrEP use increased from zero in 2004, 2008, and 2011 to 9.6 % in 2014. The proportion of men with no condomless anal sex partners dropped from 60.6 % in 2004, to 58.2 % in 2008, to 54.2 % in 2011, to 40.2 % in 2014. Consistent condom use decreased from 36.8 % in 2004, and 30.5 % in 2008 and 2011, to 18.3 % in 2014. PrEP's introduction and scale-up enters in a pre-existing trend of decreasing condom use and increasing sexually transmitted infections among MSM which may be accelerating in recent years. While PrEP use should be scaled up as a prevention option among those who would benefit most, we believe that public health officials need to be realistic about the possibility that condom use could very well continue to decline as PrEP use increases, and to an extent that may not be directly or indirectly offset by PrEP.

Pre-exposure Prophylaxis for HIV Prevention: Why, What, Who and How

Pre-exposure prophylaxis (PrEP) offers a promising new approach to HIV prevention. It is protective against HIV infection across populations and has few significant safety risks and little evidence of behavioural risk compensation. This article summarises the evidence behind HIV PrEP as an intervention, populations that may benefit, current guidelines and programmes, and the cost-effectiveness modelling of this strategy.

Human Immunodeficiency Virus, Other Sexually Transmitted Infections, and Sexual and Reproductive Health in Lesbian, Gay, Bisexual, Transgender Youth

Lesbian, gay, bisexual, transgender (LGBT), and questioning youth represent a diverse population who are affected by many sexual health inequities, including increased risk for human immunodeficiency virus (HIV) and sexually transmitted infections (STIs). To provide comprehensive sexual health care for LGBT youth, providers should set the stage with a nonjudgmental, respectful tone. Providers should be competent in recognizing symptoms of STIs and HIV and aware of the most up-to-date screening guidelines for LGBT youth. Sexual health visits should also focus on prevention, including safer sex practices, HIV pre-exposure and post-exposure prophylaxis, family planning, and immunization for hepatitis and human papillomavirus.

Engagement of Gay Men and Other Men Who Have Sex with Men (MSM) in the Response to HIV: A Critical Step in Achieving an AIDS-Free Generation

Men who have sex with men (MSM) continue to be at elevated risk for HIV acquisition and transmission secondary to biological and behavioral characteristics, social and sexual network characteristics, community environmental factors, and structural factors. HIV incidence rates remain high among MSM in both low- and high-income settings, and in both concentrated and more generalized HIV epidemic settings. While data quality tends to be poorer, the best estimates collectively suggest that MSM have up to 20 times the odds of living with HIV as compared to other reproductive aged adults across low- and middle-income countries. Recent prevention strategies to lower biological HIV transmission and acquisition risks, including the early use of antiretrovirals to decrease infectiousness for those living with HIV, and pre-exposure prophylaxis for those at significant risk of HIV acquisition, have demonstrated the potential to change the trajectory of the HIV epidemics among MSM. However, the coverage and effectiveness of these approaches is limited by structural factors including the punitive legal frameworks and institutional discrimination that contribute to limited uptake, challenges to adherence, and suboptimal health-seeking behaviors among MSM. More intensive efforts will be required to reach MSM who do not currently have access to relevant and effective prevention and treatment services or elect not to access these services given enacted and/or perceived stigma. Respect for human rights, including efforts to aggressively confront and combat the forms of stigma that are preventing us from achieving an AIDS-Free generation, are needed for all people including gay men and other MSM.

High Willingness to Use HIV Pre-Exposure Prophylaxis Among Transgender Women in Argentina

Purpose: In Argentina, transgender women face a disproportionately high prevalence of HIV infection (34%). Although not currently approved in Argentina, pre-exposure prophylaxis (PrEP) may offer a potential effective HIV prevention tool for this population. In this study, we assessed the willingness to use PrEP among transgender women in Argentina. Methods: Data were drawn from a nationwide cross-sectional survey conducted among transgender women in 2013. Using multivariable logistic regression, we assessed the prevalence of and factors associated with willingness to use PrEP among transgender women with negative or unknown HIV status. Results: This study included 337 transgender women (278 HIV negative and 59 with unknown HIV status), most of whom had a history of sex work involvement (81.8%). Overall, 301 (89.3%) expressed willingness to use PrEP. In a multivariable analysis, having casual sexual partners was positively associated with willingness to use PrEP (adjusted odds ratio [AOR]=4.26, 95% confidence interval [CI] 1.73-10.51), while discrimination by healthcare workers was negatively associated (AOR=0.33, 95% CI 0.12-0.88). Conclusion: We found high levels of willingness to use PrEP among transgender women in Argentina, suggesting that there is high perception of HIV risk in this population. However, discrimination by healthcare workers was a strong negative correlate of willingness to use PrEP, suggesting that multilevel interventions that address gender-based stigma in healthcare settings will be critical for the success of PrEP as an HIV prevention strategy in this population.

What are the characteristics of, and clinical outcomes in men who have sex with men prescribed HIV postexposure prophylaxis following sexual exposure (PEPSE) at sexual health clinics in England?

OBJECTIVES

To explore the risk factors for, and clinical outcomes in men who have sex with men (MSM) prescribed HIV postexposure prophylaxis following sexual exposure (PEPSE) at sexual health clinics (SHCs) in England.

METHODS

National STI surveillance data were extracted from the genitourinary medicine clinic activity dataset (GUMCADv2) for 2011-2014. Quarterly and annual trends in the number of episodes where PEPSE was prescribed were analysed by gender and sexual risk. Risk factors associated with being prescribed PEPSE among MSM attendees were explored using univariable and multivariable logistic regression. Subsequent HIV acquisition from 4 months after initiating PEPSE was assessed using multivariable Cox proportional hazards models, stratified by clinical risk profiles.

RESULTS

During 2011-2014, there were 24 004 episodes where PEPSE was prescribed at SHCs, of which 69% were to MSM. The number of episodes where PEPSE was prescribed to MSM increased from 2383 in 2011 to 5944 in 2014, and from 1384 to 2226 for heterosexual men and women. 15% of MSM attendees received two or more courses of PEPSE. Compared with MSM attendees not prescribed PEPSE, MSM prescribed PEPSE were significantly more likely to have been diagnosed with a bacterial STI in the previous 12 months (adjusted OR (95% CI)-gonorrhoea: 11.6 (10.5 to 12.8); chlamydia: 5.02 (4.46 to 5.67); syphilis: 2.25 (1.73 to 2.93)), and were more likely to subsequently acquire HIV (adjusted HR (aHR) (95% CI)-single PEPSE course: 2.54 (2.19 to 2.96); two or more PEPSE courses: aHR (95% CI) 4.80 (3.69 to 6.25)). The probability of HIV diagnosis was highest in MSM prescribed PEPSE who had also been diagnosed with a bacterial STI in the previous 12 months (aHR (95% CI): 6.61 (5.19 to 8.42)).

CONCLUSIONS

MSM prescribed PEPSE are at high risk of subsequent HIV acquisition and our data show further risk stratification by clinical and PEPSE prescribing history is possible, which might inform clinical practice and HIV prevention initiatives in MSM.

Pre-exposure prophylaxis (PrEP) for men who have sex with men in Europe: review of evidence for a much needed prevention tool

In many Western countries with good coverage of antiretroviral treatment (ART) programmes the annual number of HIV infections is still high and not (yet) declining among men who have sex with men (MSM). This might indicate that antiretroviral treatment roll-out alone will not turn around the course of the epidemic and that new, additional tools are needed. Antiretrovirals used as prevention tools for people not yet infected with HIV, such as pre-exposure prophylaxis (PrEP) could be such important additional tools. PrEP is a new type of biomedical prevention, which involves the use of antiretrovirals before, during and after (periods of) sexual exposure to HIV. In this review, we will focus on PrEP as a new prevention tool for MSM at high risk in Europe, including its evidence for effectiveness, challenges for implementation, ongoing European demonstration studies; as well as how PrEP relates to other existing prevention tools. In light of European Medicines Agency's recent recommendation for approval of PrEP we briefly review the potential implications.

Model Linking Plasma and Intracellular Tenofovir/Emtricitabine with Deoxynucleoside Triphosphates

The coformulation of the nucleos(t)ide analogs (NA) tenofovir (TFV) disoproxil fumarate (TDF) and emtricitabine (FTC) is approved for HIV-infection treatment and prevention. Plasma TFV and FTC undergo complicated hybrid processes to form, accumulate, and retain as their active intracellular anabolites: TFV-diphosphate (TFV-DP) and FTC-triphosphate (FTC-TP). Such complexities manifest in nonlinear intracellular pharmacokinetics (PK). In target cells, TFV-DP/FTC-TP compete with endogenous deoxynucleoside triphosphates (dNTP) at the active site of HIV reverse transcriptase, underscoring the importance of analog:dNTP ratios for antiviral efficacy. However, NA such as TFV and FTC have the potential to disturb the dNTP pool, which could augment or reduce their efficacies. We conducted a pharmacokinetics-pharmacodynamics (PKPD) study among forty subjects receiving daily TDF/FTC (300 mg/200 mg) from the first-dose to pharmacological intracellular steady-state (30 days). TFV/FTC in plasma, TFV-DP/FTC-TP and dNTPs in peripheral blood mononuclear cells (PBMC) were quantified using validated LC/MS/MS methodologies. Concentration-time data were analyzed using nonlinear mixed effects modeling (NONMEM). Formations and the accumulation of intracellular TFV-DP/FTC-TP was driven by plasma TFV/FTC, which was described by a hybrid of first-order formation and saturation. An indirect response link model described the interplay between TFV-DP/FTC-TP and the dNTP pool change. The EC₅₀ (interindividual variability, (%CV)) of TFV-DP and FTC-TP on the inhibition of deoxyadenosine triphosphate (dATP) and deoxycytidine triphosphate (dCTP) production were 1020 fmol/10⁶ cells (130%) and 44.4 pmol/10⁶ cells (82.5%), resulting in (90% prediction interval) 11% (0.45%, 53%) and 14% (2.6%, 35%) reductions. Model simulations of analog:dNTP molar ratios using IPERGAY dosing suggested that FTC significantly contributes to the protective effect of preexposure prophylaxis (PrEP). Simulation-based intracellular operational multiple dosing half-lives of TFV-DP and FTC-TP were 6.7 days and 33 hours. This model described the formation of intracellular TFV-DP/FTC-TP and the interaction with dNTPs, and can be used to simulate analog:dNTP time course for various dosing strategies.