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Background: Seroadaptive behaviors refer to a wide range of harm reduction practices to decrease HIV transmission risk. Effective implementation of seroadaptive behaviors is dependent on knowledge of one's own serostatus and that of one's sexual partners. Partner-level and environmental-level attributes may affect seroadaptation practices. We assessed factors associated with seroadaptive behaviors., Methods: Men who have sex with men and transgender women were recruited from an HIV pre-exposure prophylaxis clinical trial (iPrEx) with study sites in the US, Peru, Ecuador, Brazil, Thailand, and South Africa. Partnership-level data were collected at the baseline visit for the 3 most recent partners. Participants were considered to have practiced seroadaptive behaviors if: (1) they believed their partner to be HIV-negative, that is, serosorting; or (2) no condomless receptive sex occurred with an HIV-positive or unknown status partner, that is, seropositioning., Results: Of 2331 participants, 41% always practiced seroadaptive behaviors, 36% sometimes did, and 23% never did. Participants enrolled at study sites in the US (P < 0.001) and Peru/Ecuador (P < 0.001) were more likely to practice seroadaptive behaviors, whereas transgender women were less likely to do so (P < 0.001). Seroadaptive behaviors were more likely to occur in relationships with steady partners (P = 0.005) and emotionally close relationships (P = 0.013)., Conclusions: Seroadaptive behaviors were more frequently observed among iPrEx participants from the US, Peru, and Ecuador study sites and among participants in relationships with partners who they were more committed to and felt emotionally close to. Our findings suggest that seroadaptive behaviors may be influenced by social norms that vary geographically and culturally., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The HIV Prevention Trials Network (HPTN) 067/Alternative Dosing to Augment PrEP Pill Taking (ADAPT) Study evaluated the feasibility of daily and nondaily human immunodeficiency virus (HIV) preexposure prophylaxis (PrEP) regimens among high-risk populations, including men who have sex with men (MSM) and transgender women, in Bangkok, Thailand and Harlem, New York. We used a mathematical model to predict the efficacy and effectiveness of different dosing regimens., Methods: An individual-based mathematical model was used to simulate annual HIV incidence among MSM cohorts. PrEP efficacy for covered sex acts, as defined in the HPTN 067/ADAPT protocol, was estimated using subgroup efficacy estimates from the preexposure prophylaxis initiative (iPrEx) trial. Effectiveness was estimated by comparison of the HIV incidence with and without PrEP use., Results: We estimated that PrEP was highly protective (85%-96% efficacy across regimens and sites) for fully covered acts. PrEP was more protective for partially covered acts in Bangkok (71%-88% efficacy) than in Harlem (62%-81% efficacy). Our model projects 80%, 62%, and 68% effectiveness of daily, time-driven, and event-driven PrEP for MSM in Harlem compared with 90%, 85%, and 79% for MSM in Bangkok. Halving the efficacy for partially covered acts decreases effectiveness by 8-9 percentage points in Harlem and by 5-9 percentage points in Bangkok across regimens., Conclusions: Our analysis suggests that PrEP was more effective among MSM in Thailand than in the United States as a result of more fully covered sex acts and more pills taken around partially covered acts. Overall, nondaily PrEP was less effective than daily PrEP, especially in the United States where the sex act coverage associated with daily use was substantially higher., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

The HPTN 067/ADAPT Study evaluated the feasibility, acceptability, patterns of adherence and coverage for three randomly assigned oral FTC/TDF pre-exposure prophylaxis (PrEP) dosing regimens to prevent HIV infection. Using qualitative methods, we explored facilitators and barriers among a subset of men who have sex with men (MSM) participants in Bangkok, Thailand. Between August 2013 and March 2014, 32 HPTN 067/ADAPT participants joined in 6 focus group discussions, and 6 attended key informant interviews. Facilitators of PrEP adherence included use of strategies to have PrEP available when needed, simplicity in regimen requirements with recognition that more complex regimens may take some time to master, ability to plan for sex, receipt of social and technology support, ability to use a PrEP regimen that best matches to one's own patterns of sex, and experiences with PrEP as a part of health and well-being. Challenges to PrEP adherence included perceptions of no or low HIV risk, difficulties following regimens when intoxicated, concerns about side effects, experience of HIV stigma, and affordability of PrEP outside of study context influencing uptake and use in the community. Preferences for regimens varied, suggesting that multiple PrEP effective regimen options should be available to fit those with different needs.

Objective: We evaluated the relationship between 2 types of social relationships, ie, (1) external support for use of HIV pre-exposure prophylaxis (PrEP) and related study supplies and (2) participants' disclosure of PrEP use and condom use and HIV PrEP adherence among daily-dosing regimen participants in HIV Prevention Trials Network (HPTN) 067, an open-label trial of oral tenofovir (TFV) disoproxil fumarate (TDF) 300 mg/emtricitabine (FTC) 200 mg., Methods: Using HPTN 067 survey data, we developed scales examining (1) Low Perceived External Support for PrEP: low perceived support by others for PrEP use or perceived negative reactions to the pill case (scoring ranges from 0 to 2) and (2) Participant-Staff Disclosure Challenges Scale, which identifies challenges to sharing nonuse of PrEP or condoms to study staff (scoring ranges from 0 to 4); these scales are the primary independent variables. Adherence, the dependent variable, was determined using log-transformed plasma TFV concentrations. generalized estimating equation (GEE) linear regression was used to assess the association between both scales and adherence., Results: Participants (n = 161) included HIV-uninfected women in South Africa, and men who have sex with men and transgender women, in Thailand and the United States. In multivariable analyses, higher scores in the Participant-Staff Disclosure Challenges Scale were significantly associated with lower PrEP adherence [exp(β) = 0.62, 95% CI: (0.46 to 0.84); P = 0.002] as were increased days since the last PrEP dose [exp(β) = 0.73, 95% CI: (0.65 to 0.83); P ≤ 0.001]., Conclusions: Given the association with adherence, study staff-participant interactions and participants' disclosure of PrEP challenges may be worthwhile intervention targets for improving PrEP adherence in confirmatory studies.

We report a case indicating that acquisition of multidrug-resistant human immunodeficiency (HIV) virus type 1 during preexposure prophylaxis with combination tenofovir disoproxil fumarate and emtricitabine or evolution of resistance after HIV seroconversion remains a risk.

HIV pre-exposure prophyalxis (PrEP) might lead individuals to view serodisclosure as unnecessary. We examined the prevalence of non-disclosure and lack of knowledge of partner status in a global cohort of men who have sex with men (MSM) and transgender women (TW) enrolled in the iPrEx Open Label Extension (OLE). We calculated prevalence ratios by fitting a logistic model and estimating predicted probabilities using marginal standardization. Prevalence of non-disclosure and lack of knowledge of partner status were highest in Thailand (73% and 74%, respectively) and lowest in the USA (23% and 37%, respectively). In adjusted analyses, PrEP use was not significantly associated with non-disclosure or lack of knowledge of partner status (p-values>0.05). We found that relationship characteristics were significantly associated with both outcomes. Non-disclosure was higher among casual (adjusted prevalence ratio [aPR] 1.54, [95% confidence interval 1.24-1.84]) and transactional sex partners (aPR 2.03, [1.44-2.62]), and among partners whom participants have known only minutes or hours before their first sexual encounter (aPR 1.62, [1.33-1.92]). Similarly, participants were less likely to know the HIV status of casual partners (aPR 1.50, [1.30-1.71]), transactional sex partners (aPR 1.62, [1.30-1.95]), and those they have known for only days or weeks (aPR 1.13, [0.99-1.27]) or minutes or hours (aPR 1.27, [1.11-1.42]). Our findings underscore the role of dyadic factors in influencing serodisclosure. Comprehensive risk reduction counseling provided in conjunction with PrEP that address relationship characteristics are needed to help patients navigate discussions around HIV status.

Background: As pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate and emtricitabine for the prevention of HIV infection is rolled out internationally, strategies to maintain effectiveness and to minimise adverse effects merit consideration. In this study, we aimed to assess reductions in renal function and predictors of renal toxicity in a large open-label study of PrEP., Methods: As part of the iPrEx open-label extension (OLE) study, men who have sex with men or transgender women aged 18-70 years who were HIV negative and had participated in three previous PrEP trials from Brazil, Ecuador, Peru, South Africa, Thailand, and the USA were enrolled into an open-label PrEP study. There were no restrictions on current renal function for enrolment into iPrEx OLE, in which participants were given combination tablets of tenofovir disoproxil fumarate (300 mg) and emtricitabine (200 mg) and advised to take one tablet per day. At follow-up sessions every 12 weeks, participants' creatinine clearance on PrEP was estimated and in a subset of participants, hair samples were collected to measure tenofovir and emtricitabine concentrations (a measure of adherence and exposure) via liquid-chromatography-tandem-mass-spectrometry. Reductions in creatinine clearance from baseline were calculated and predictors of decline were identified by use of multivariate models. iPrEx is registered with ClinicalTrials.com, number NCT00458393., Findings: Baseline characteristics were similar between all participants in iPrEx-OLE (1224 participants with 7475 person-visits) and those participating in the hair substudy (220 participants with 1114 person-visits). During a median of 72 weeks, the mean decline in creatinine clearance was -2·9% (95% CI -2·4 to -3·4; p trend <0·0001), but declines were greater for those who started PrEP at older ages: participants aged 40-50 years at baseline had declines of -4·2% (95% CI -2·8 to -5·5) and participants older than 50 years at baseline had declines of -4·9% (-3·1 to -6·8). In multivariate models, age and baseline creatinine clearance less than 90 mL/min predicted declines in renal function. We identified a monotonic association between percentage decrease in creatinine clearance and the number of doses of tenofovir disoproxil fumarate and emtricitabine taken per week, as estimated by hair concentrations of tenofovir and emtricitabine (p trend =0·008)., Interpretation: Our data suggest that the frequency of safety monitoring for PrEP might need to be different between age groups and that pharmacological measures can monitor for toxic effects as well as adherence., Funding: National Institutes of Health., (Copyright © 2016 Elsevier Ltd. All rights reserved.)