HIV incidence in a multinational cohort of men and transgender women who have sex with men in sub-Saharan Africa: Findings from HPTN 075.

Few studies have assessed HIV incidence in men who have sex with men (MSM) and transgender women (TGW) in sub-Saharan Africa (SSA). We assessed HIV incidence and its correlates among MSM and TGW in SSA enrolled in the prospective, multi-country HIV Prevention Trials Network (HPTN) 075 study, conducted from 2015 to 2017. Participants were enrolled at four sites in SSA (Kisumu, Kenya; Blantyre, Malawi; Cape Town and Soweto, South Africa). Eligible participants reported male sex assignment at birth, were 18 to 44 years of age, and had engaged in anal intercourse with a man in the preceding three months. Participation involved five study visits over 12 months. Visits included behavioral assessments and testing for HIV and sexually transmitted infections. Twenty-one of 329 persons acquired HIV during the study [incidence rate: 6.96/100 person-years (PY) (95% CI: 4.3, 10.6)]. Among TGW, HIV incidence was estimated to be 8.4/100 PY (95% CI: 2.3, 21.5). Four participants were found to have acute HIV infection at their first HIV-positive visit. HIV incidence varied among the four study sites, ranging from 1.3/100 PY to 14.4/100 PY. In multivariate longitudinal analysis, factors significantly associated with HIV acquisition were engagement in unprotected receptive anal intercourse [adjusted hazard ratio (AHR) 5.8, 95% confidence interval (CI): 2.4, 14.4] and incident rectal gonorrhea and/or chlamydia (AHR: 2.7, 95% CI: 1.1, 6.8). The higher HIV incidence in Cape Town compared to Blantyre could be explained by the higher prevalence of several risk factors for HIV infection among participants in Cape Town. Annual HIV incidence observed in this study is substantially higher than reported HIV incidence in the general populations in the respective countries and among MSM in the United States. Intensification of HIV prevention efforts for MSM and TGW in SSA is urgently needed.

The feasibility of recruiting and retaining men who have sex with men and transgender women in a multinational prospective HIV prevention research cohort study in sub-Saharan Africa (HPTN 075).

INTRODUCTION: Men who have sex with men (MSM) and transgender women (TGW) in sub-Saharan Africa (SSA) are profoundly affected by HIV with high HIV prevalence and incidence. This population also faces strong social stigma and legal barriers, potentially impeding participation in research. To date, few multi-country longitudinal HIV research studies with MSM/TGW have been conducted in SSA. Primary objective of the HIV Prevention Trials Network (HPTN) 075 study was to assess feasibility of recruiting and retaining a multinational prospective cohort of MSM/TGW in SSA for HIV prevention research. METHODS: HPTN 075, conducted from 2015 to 2017, was designed to enroll 400 MSM/TGW at four sites in SSA (100 per site: Kisumu, Kenya; Blantyre, Malawi; Cape Town, South Africa; and Soweto, South Africa). The number of HIV-positive persons was capped at 20 per site; HIV-positive persons already in care were excluded from participation. The one-year study included five biobehavioural assessments. Community-based input and risk mitigation protocols were included in study design and conduct. RESULTS: Of 624 persons screened, 401 were enrolled. One in five participants was classified as transgender. Main reasons for ineligibility included: (a) being HIV positive after the cap was reached (29.6%); (b) not reporting anal intercourse with a man in the preceding three months (20.6%); and (c) being HIV positive and already in care (17.5%). Five (1.2%) participants died during the study (unrelated to study participation). 92.9% of the eligible participants (368/396) completed the final study visit and 86.1% participated in all visits. The main, overlapping reasons for early termination included being (a) unable to adhere to the visit schedule, predominantly because of relocation (46.4%), and (b) unable to contact the participant (32.1%). Participants reported strong motivation to participate and few participation barriers. Four participants reported social harms (loss of confidentiality and sexual harassment by study staff) that were successfully addressed. CONCLUSIONS: HPTN 075 successfully enrolled a multinational sample of MSM/TGW in SSA in a prospective HIV prevention research study with a high retention rate and few documented social harms. This supports the feasibility of conducting large-scale research trials in this population to address its urgent, unmet HIV prevention needs.

Applying the Behavioural and Social Sciences Research (BSSR) Functional Framework to HIV Cure Research.

INTRODUCTION: The search for an HIV cure involves important behavioural and social processes that complement the domains of biomedicine. However, the field has yet to tap into the full potential of behavioural and social sciences research (BSSR). In this article, we apply Gaist and Stirratt's BSSR Functional Framework to the field of HIV cure research. DISCUSSION: The BSSR Functional Framework describes four key research domains: (1) basic BSSR (understanding basic behavioural and social factors), (2) elemental BSSR (advancing behavioural and social interventions), (3) supportive BSSR (strengthening biomedically focused clinical trials), and (4) integrative BSSR (building multi-disciplinary combination approaches for real-world implementation). In revisiting and applying the BSSR Functional Framework, we clarify the importance of BSSR in HIV cure research by drawing attention to such things as: how language and communication affect the meaning of "cure" to people living with HIV (PLHIV) and broader communities; how cure affects the identity and social position of PLHIV; counselling and support interventions to address the psychosocial needs and concerns of study participants related to analytical treatment interruptions (ATIs); risk reduction in the course of ATI study participation; motivation, acceptability, and decision-making processes of potential study participants related to different cure strategies; HIV care providers' perceptions and attitudes about their patients' participation in cure research; potential social harms or adverse social events associated with cure research participation; and the scalability of a proven cure strategy in the context of further advances in HIV prevention and treatment. We also discuss the BSSR Functional Framework in the context of ATIs, which involve processes at the confluence of the BSSR domains. CONCLUSIONS: To move HIV cure regimens through the translational research pathway, attention will need to be paid to both biomedical and socio-behavioural elements. BSSR can contribute an improved understanding of the human and social dimensions related to HIV cure research and the eventual application of HIV cure regimens. The BSSR Functional Framework provides a way to identify advances, gaps and opportunities to craft an integrated, multi-disciplinary approach at all stages of cure research to ensure the real-world applicability of any strategy that shows promise.

HIV testing and the HIV care continuum among sub-Saharan African men who have sex with men and transgender women screened for participation in HPTN 075.

Throughout the world, men who have sex with men (MSM) are at increased risk for HIV infection compared to heterosexual men. Little is known about awareness of HIV infection and other gaps in the HIV care continuum for MSM, especially in sub-Saharan Africa (SSA). This information is urgently needed to address the HIV epidemic in this population. This study assessed gaps in the HIV care continuum among persons screened for participation in a multi-country prospective study that evaluated the feasibility of recruiting and retaining MSM for HIV prevention studies in SSA (HIV Prevention Trials Network (HPTN) 075, conducted in four cities in Kenya, Malawi, and South Africa). Participants were recruited using site-specific strategies, that included outreach and informal networks. Transgender women (TW) were eligible to participate. During screening, 601 MSM and TW were tested for HIV infection and asked about prior HIV testing, HIV status, engagement in care, and HIV treatment. Viral load testing and retrospective antiretroviral (ARV) drug testing were performed for HIV-infected participants. Most participants (92.2%) had a prior HIV test; 42.1% were last tested >6 months earlier. HIV prevalence was 30.4%. HIV infection was associated with older age and identifying as female or transgender; 43.7% of the HIV-infected participants were newly diagnosed, especially younger persons and persons with a less recent HIV test. Almost a third of previously-diagnosed participants were not linked to care. Most participants (88.7%) in care were on ARV treatment (ART). Only about one-quarter of all HIV-infected participants were virally suppressed. These findings demonstrate substantial prevalence of undiagnosed HIV infection and sub-optimal HIV care engagement among MSM and TW in SSA. Increased HIV testing frequency and better linkage to care represent critical steps in preventing further HIV transmission in this population. Once in care, gaps in the HIV care continuum appear less critical.

Mental health and HIV/AIDS: the need for an integrated response.

: Tremendous biomedical advancements in HIV prevention and treatment have led to aspirational efforts to end the HIV epidemic. However, this goal will not be achieved without addressing the significant mental health and substance use problems among people living with HIV (PLWH) and people vulnerable to acquiring HIV. These problems exacerbate the many social and economic barriers to accessing adequate and sustained healthcare, and are among the most challenging barriers to achieving the end of the HIV epidemic. Rates of mental health problems are higher among both people vulnerable to acquiring HIV and PLWH, compared with the general population. Mental health impairments increase risk for HIV acquisition and for negative health outcomes among PLWH at each step in the HIV care continuum. We have the necessary screening tools and efficacious treatments to treat mental health problems among people living with and at risk for HIV. However, we need to prioritize mental health treatment with appropriate resources to address the current mental health screening and treatment gaps. Integration of mental health screening and care into all HIV testing and treatment settings would not only strengthen HIV prevention and care outcomes, but it would additionally improve global access to mental healthcare.

Evaluation of a computer-based and counseling support intervention to improve HIV patients' viral loads.

We sought to integrate a brief computer and counseling support intervention into the routine practices of HIV clinics and evaluate effects on patients' viral loads. The project targeted HIV patients in care whose viral loads exceeded 1000 copies/ml at the time of recruitment. Three HIV clinics initiated the intervention immediately, and three other HIV clinics delayed onset for 16 months and served as concurrent controls for evaluating outcomes. The intervention components included a brief computer-based intervention (CBI) focused on antiretroviral therapy adherence; health coaching from project counselors for participants whose viral loads did not improve after doing the CBI; and behavioral screening and palm cards with empowering messages available to all patients at intervention clinics regardless of viral load level. The analytic cohort included 982 patients at intervention clinics and 946 patients at control clinics. Viral loads were assessed at 270 days before recruitment, at time of recruitment, and +270 days later. Results indicated that both the control and intervention groups had significant reductions in viral load, ending with approximately the same viral level at +270 days. There was no evidence that the CBI or the targeted health coaching was responsible for the viral reduction in the intervention group. Results may stem partially from statistical regression to the mean in both groups. Also, clinical providers at control and intervention clinics may have taken action (e.g., conversations with patients, referrals to case managers, adherence counselors, mental health, substance use specialists) to help their patients reduce their viral loads. In conclusion, neither a brief computer-based nor targeted health coaching intervention reduced patients' viral loads beyond levels achieved with standard of care services available to patients at well-resourced HIV clinics.

Gaps Up To 9 Months Between HIV Primary Care Visits Do Not Worsen Viral Load.

Current guidelines specify that visit intervals with viral monitoring should not exceed 6 months for HIV patients. Yet, gaps in care exceeding 6 months are common. In an observational cohort using US patients, we examined the association between gap length and changes in viral load status and sought to determine the length of the gap at which significant increases in viral load occur. We identified patients with gaps in care greater than 6 months from 6399 patients from six US HIV clinics. Gap strata were >6 to <7, 7 to <8, 8 to <9, 9 to <12, and ≥12 months, with viral load measurements matched to the opening and closing dates for the gaps. We examined visit gap lengths in association with two viral load measurements: continuous (log10 viral load at gap opening and closing) and dichotomous (whether patients initially suppressed but lost viral suppression by close of the care gap). Viral load increases were nonsignificant or modest when gap length was <9 months, corresponding to 10% or fewer patients who lost viral suppression. For gaps ≥12 months, there was a significant increase in viral load as well as a much larger loss of viral suppression (in 23% of patients). Detrimental effects on viral load after a care gap were greater in young patients, black patients, and those without private health insurance. On average, shorter gaps in care were not detrimental to patient viral load status. HIV primary care visit intervals of 6 to 9 months for select patients may be appropriate.

Daily and Nondaily Oral Preexposure Prophylaxis in Men and Transgender Women Who Have Sex With Men: The Human Immunodeficiency Virus Prevention Trials Network 067/ADAPT Study.

Background: Nondaily dosing of oral preexposure prophylaxis (PrEP) may provide equivalent coverage of sex events compared with daily dosing. Methods: At-risk men and transgender women who have sex with men were randomly assigned to 1 of 3 dosing regimens: 1 tablet daily, 1 tablet twice weekly with a postsex dose (time-driven), or 1 tablet before and after sex (event-driven), and were followed for coverage of sex events with pre- and postsex dosing measured by weekly self-report, drug concentrations, and electronic drug monitoring. Results: From July 2012 to May 2014, 357 participants were randomized. In Bangkok, the coverage of sex events was 85% for the daily arm compared with 84% for the time-driven arm (P = .79) and 74% for the event-driven arm (P = .02). In Harlem, coverage was 66%, 47% (P = .01), and 52% (P = .01) for these groups. In Bangkok, PrEP medication concentrations in blood were consistent with use of ≥2 tablets per week in >95% of visits when sex was reported in the prior week, while in Harlem, such medication concentrations occurred in 48.5% in the daily arm, 30.9% in the time-driven arm, and 16.7% in the event-driven arm (P < .0001). Creatinine elevations were more common in the daily arm (P = .050), although they were not dose limiting. Conclusions: Daily dosing recommendations increased coverage and protective drug concentrations in the Harlem cohort, while daily and nondaily regimens led to comparably favorable outcomes in Bangkok, where participants had higher levels of education and employment. Clinical Trials Registration: NCT01327651.

Advancing the Science and Practice of Medication Adherence.

Medication adherence remains a significant unmet challenge for optimizing patient outcomes. Recent advances in the conceptualization, measurement, and support of medication adherence offer fresh opportunities to make a meaningful impact on adherence-related behavior and outcomes. These advances emphasize the multifaceted and dynamic nature of medication adherence, provide novel methods for monitoring medication adherence in clinical care, and articulate a set of multilevel strategies to more effectively improve and sustain medication adherence. Here, we offer recommendations for how clinicians can better engage with, and benefit from, these innovations to improve patient medication adherence and associated treatment outcomes.

Daily and non-daily pre-exposure prophylaxis in African women (HPTN 067/ADAPT Cape Town Trial): a randomised, open-label, phase 2 trial.

BACKGROUND: The relative feasibility and acceptability of daily versus non-daily dosing of oral HIV pre-exposure prophylaxis (PrEP) among women are unknown. We aimed to investigate the feasibility of non-daily PrEP regimens in adult women. METHODS: We did a randomised, open-label, phase 2 clinical trial (HPTN 067/ADAPT) of oral PrEP with emtricitabine plus tenofovir disoproxil fumarate at a research centre in Cape Town, South Africa. Participants were adult women (age ≥18 years) who received directly observed dosing once a week for 5 weeks followed by random assignment (1:1:1) at week 6 to one of three unblinded PrEP regimens for self-administered dosing over 24 weeks: daily; time-driven (twice a week plus a post-sex dose); or event-driven (one tablet both before and after sex). Primary outcomes were PrEP coverage (at least one dose within the 4 days before sex and one dose within 24 h after sex), pills needed or used to achieve regimen-specific adherence and coverage, and symptoms and side-effects. All analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01327651; the trial is completed and this report presents the final analysis. FINDINGS: Between Sept 12, 2011, and Oct 3, 2012, 191 women were enrolled to the trial. 178 (93%) completed directly observed dosing and were randomly assigned one of the three PrEP regimens for the self-administered phase: 59 were allocated the daily regimen, 59 the time-driven regimen, and 60 the event-driven regimen. Median age of women was 26 years (IQR 21-37; range 18-52). In women allocated the daily regimen, 1459 (75%) of 1952 sex events were covered by PrEP, compared with 599 (56%) of 1074 sex events among those assigned the time-driven regimen (odds ratio [OR] 2·35, 95% CI 1·43-3·83; p=0·0007) and 798 (52%) of 1542 sex events among those allotted the event-driven regimen (2·76, 1·68-4·53; p<0·0001). Fewer pills were needed for complete adherence in women allocated non-daily regimens (vs daily regimen, relative mean 2·53 [95% CI 2·39-2·69] for the time-driven regimen and 4·16 [3·59-4·82] for the event-driven regimen; p<0·0001). Side-effects were uncommon. Eight HIV seroconversions occurred overall, with four documented during the self-administered phase (two with the time-driven regimen and two with the event-driven regimen). Adherence to the assigned regimen was 75% (7283 of 9652 doses taken) for women allocated the daily regimen compared with 65% for those assigned the time-driven regimen (2367 of 3616 doses taken; p=0·0028) and 53% for those allotted the event-driven regimen (1161 of 2203 doses taken; p<0·0001). When sex was reported in the previous week, PrEP drugs were detected (above the lower limits of quantification) more frequently in women assigned the daily regimen (73 [68%] of 107 samples) than in those allocated the time-driven regimen (42 [58%] of 72 samples) and the event-driven regimen (41 [41%] of 99 samples). INTERPRETATION: Daily PrEP dosing resulted in higher coverage of sex events, increased adherence to the regimen, and augmented drug concentrations than did either time-driven or event-driven dosing. These findings support recommendations for daily use of PrEP with oral emtricitabine plus tenofovir disoproxil fumarate in women. FUNDING: HIV Prevention Trials Network.

Characterising HIV transmission risk among US patients with HIV in care: a cross-sectional study of sexual risk behaviour among individuals with viral load above 1500 copies/mL.

OBJECTIVES: Viral load and sexual risk behaviour contribute to HIV transmission risk. High HIV viral loads present greater transmission risk than transient viral 'blips' above an undetectable level. This paper therefore characterises sexual risk behaviour among patients with HIV in care with viral loads>1500 copies/mL and associated demographic characteristics. METHODS: This cross-sectional study was conducted at six HIV outpatient clinics in USA. The study sample comprises 1315 patients with HIV with a recent viral load >1500 copies/mL. This study sample was drawn from a larger sample of individuals with a recent viral load >1000 copies/mL who completed a computer-assisted self-interview (CASI) regarding sexual risk practices in the last 2 months. The study sample was 32% heterosexual men, 38% men who have sex with men (MSM) and 30% women. RESULTS: Ninety per cent of the sample had their viral load assay within 60 days of the CASI. Thirty-seven per cent reported being sexually active (vaginal or anal intercourse) in the last 2 months. Most of the sexually active participants reported always using condoms (56.9%) or limiting condomless sex to seroconcordant partners (serosorting; 29.2% overall and 42.9% among MSM). Among sexually active participants who reported condomless anal or vaginal sex with an at-risk partner (14%), most had viral loads>10 000 copies/mL (62%). CONCLUSIONS: A relatively small number of patients with HIV in care with viral loads above 1500 copies/mL reported concurrent sexual transmission risk behaviours. Most of the individuals in this small group had markedly elevated viral loads, increasing the probability of transmission. Directing interventions to patients in care with high viral loads and concurrent risk behaviour could strengthen HIV prevention and reduce HIV infections. TRIAL REGISTRATION NUMBER: NCT02044484, completed.

Improving antiretroviral therapy adherence in resource-limited settings at scale: a discussion of interventions and recommendations.

Introduction: Successful population-level antiretroviral therapy (ART) adherence will be necessary to realize both the clinical and prevention benefits of antiretroviral scale-up and, ultimately, the end of AIDS. Although many people living with HIV are adhering well, others struggle and most are likely to experience challenges in adherence that may threaten virologic suppression at some point during lifelong therapy. Despite the importance of ART adherence, supportive interventions have generally not been implemented at scale. The objective of this review is to summarize the recommendations of clinical, research, and public health experts for scalable ART adherence interventions in resource-limited settings. Methods: In July 2015, the Bill and Melinda Gates Foundation convened a meeting to discuss the most promising ART adherence interventions for use at scale in resource-limited settings. This article summarizes that discussion with recent updates. It is not a systematic review, but rather provides practical considerations for programme implementation based on evidence from individual studies, systematic reviews, meta-analyses, and the World Health Organization Consolidated Guidelines for HIV, which include evidence from randomized controlled trials in low- and middle-income countries. Interventions are categorized broadly as education and counselling; information and communication technology-enhanced solutions; healthcare delivery restructuring; and economic incentives and social protection interventions. Each category is discussed, including descriptions of interventions, current evidence for effectiveness, and what appears promising for the near future. Approaches to intervention implementation and impact assessment are then described. Results and discussion: The evidence base is promising for currently available, effective, and scalable ART adherence interventions for resource-limited settings. Numerous interventions build on existing health care infrastructure and leverage available resources. Those most widely studied and implemented to date involve peer counselling, adherence clubs, and short message service (SMS). Many additional interventions could have an important impact on ART adherence with further development, including standardized counselling through multi-media technology, electronic dose monitoring, decentralized and differentiated models of care, and livelihood interventions. Optimal targeting and tailoring of interventions will require improved adherence measurement. Conclusions: The opportunity exists today to address and resolve many of the challenges to effective ART adherence, so that they do not limit the potential of ART to help bring about the end of AIDS.

The Roles of Behavioral and Social Science Research in the Fight Against HIV/AIDS: A Functional Framework.

Landmark advances have been made in HIV/AIDS prevention and treatment. These include proof-of-concept and public health implementation of preexposure prophylaxis and "treatment as prevention" to reduce HIV transmission as well as definitive evidence of the clinical gain from early antiretroviral treatment initiation. Significant progress has been made in understanding and addressing the social contexts and behavioral factors that impact HIV prevention, care, and treatment interventions. These include facilitating uptake of testing and counseling, developing technology-based interventions that increase viral suppression, reducing HIV/AIDS-related stigma, and addressing other sociobehavioral and structural barriers to care and treatment. This evolving landscape provides an important juncture to assess current and future directions for HIV/AIDS behavioral and social science research (BSSR). We propose a functional framework for HIV/AIDS-related BSSR, highlighting 4 primary BSSR domains: (1) understanding vulnerable populations and contexts of risk ("Basic BSSR"); (2) improving behavioral and social factor approaches to risk reduction, prevention, and care ("Elemental BSSR"); (3) strengthening the design and outcomes of biomedically focused research in HIV/AIDS treatment and prevention ("Supportive BSSR"); and (4) contributing building blocks to integrated HIV/AIDS prevention and treatment approaches ("Integrative BSSR"). These domains and their resulting confluence at the highest level underscore how fundamental and essential BSSR is to current and future efforts to prevent, treat, and cure HIV/AIDS.

Single Viral Load Measurements Overestimate Stable Viral Suppression Among HIV Patients in Care: Clinical and Public Health Implications.

BACKGROUND: The HIV continuum of care paradigm uses a single viral load test per patient to estimate the prevalence of viral suppression. We compared this single-value approach with approaches that used multiple viral load tests to examine the stability of suppression. METHODS: The retrospective analysis included HIV patients who had at least 2 viral load tests during a 12-month observation period. We assessed the (1) percent with suppressed viral load (<200 copies/mL) based on a single test during observation, (2) percent with suppressed viral loads on all tests during observation, (3) percent who maintained viral suppression among patients whose first observed viral load was suppressed, and (4) change in viral suppression status comparing first with last measurement occasions. Prevalence ratios compared demographic and clinical subgroups. RESULTS: Of 10,942 patients, 78.5% had a suppressed viral load based on a single test, whereas 65.9% were virally suppressed on all tests during observation. Of patients whose first observed viral load was suppressed, 87.5% were suppressed on all subsequent tests in the next 12 months. More patients exhibited improving status (13.3% went from unsuppressed to suppressed) than worsening status (5.6% went from suppressed to unsuppressed). Stable suppression was less likely among women, younger patients, black patients, those recently diagnosed with HIV, and those who missed ≥1 scheduled clinic visits. CONCLUSIONS: Using single viral load measurements overestimated the percent of HIV patients with stable suppressed viral load by 16% (relative difference). Targeted clinical interventions are needed to increase the percent of patients with stable suppression.

Self-report measures of medication adherence behavior: recommendations on optimal use.

Medication adherence plays an important role in optimizing the outcomes of many treatment and preventive regimens in chronic illness. Self-report is the most common method for assessing adherence behavior in research and clinical care, but there are questions about its validity and precision. The NIH Adherence Network assembled a panel of adherence research experts working across various chronic illnesses to review self-report medication adherence measures and research on their validity. Self-report medication adherence measures vary substantially in their question phrasing, recall periods, and response items. Self-reports tend to overestimate adherence behavior compared with other assessment methods and generally have high specificity but low sensitivity. Most evidence indicates that self-report adherence measures show moderate correspondence to other adherence measures and can significantly predict clinical outcomes. The quality of self-report adherence measures may be enhanced through efforts to use validated scales, assess the proper construct, improve estimation, facilitate recall, reduce social desirability bias, and employ technologic delivery. Self-report medication adherence measures can provide actionable information despite their limitations. They are preferred when speed, efficiency, and low-cost measures are required, as is often the case in clinical care.

Factors Associated with Adherence and Concordance Between Measurement Strategies in an HIV Daily Oral Tenofovir/Emtricitibine as Pre-exposure Prophylaxis (Prep) Clinical Trial, Botswana, 2007-2010.

This study examined study product adherence and its determinants in the Botswana oral pre-exposure prophylaxis efficacy trial. Among the 1,219 participants, the mean adherence by pill count and 3-day self-report was 94 % for each. In multivariable models, pill count adherence was significantly associated with adverse events (nausea, dizziness, vomiting) (RR 0.98 95 % CI 0.98-1.00; p = 0.03) and side effect concerns (RR 0.98 95 % CI 0.96-0.99; p = 0.01). Self-reported adherence was significantly associated with having an HIV-positive partner (RR 1.02 95 % CI 1.00-1.04; p = 0.02) and Francistown residence (RR 0.98 95 % CI 0.96, 0.99; p = 0.0001). Detectable drug concentrations showed modest associations with self-report and pill count adherence, and drug levels were higher among those self-reporting 100 % adherence than those reporting <100 %. Most common adherence barriers involved refill delays and other logistic challenges; cellphone alarm reminder use was the most common facilitator.