Comprehension of informed consent and voluntary participation in registration cohorts for phase IIb HIV vaccine trial in Dar Es Salaam, Tanzania: a qualitative descriptive study.

BACKGROUND: Informed consent as stipulated in regulatory human research guidelines requires volunteers to be well-informed about what will happen to them in a trial. However, researchers may be faced with the challenge of how to ensure that a volunteer agreeing to take part in a clinical trial is truly informed. This study aimed to find out volunteers' comprehension of informed consent and voluntary participation in Human Immunodeficiency Virus (HIV) clinical trials during the registration cohort. METHODS: We conducted a qualitative study among volunteers who were enrolled in the registration cohort of HIV clinical trials in Dar es Salaam, Tanzania. A purposive sampling strategy was used to obtain twenty study participants. The data were collected between June and September 2020 using a semi-structured interview guide. In-depth interviews were used to collect the data to obtain deep insights of the individual study participants on the comprehension of informed consent and participation in the clinical trial. A thematic analysis approach was used to analyze the data. Themes and subthemes were supported by the quotes from the participants. RESULTS: Volunteers described comprehension of informed consent from different perspectives. They reported that various components of the informed consent such as study procedure, confidentiality, risk and benefits were grasped during engagement meetings. Furthermore, the volunteers' decision to participate in the registration cohort was voluntary. However, trial aspects such as health insurance, free condoms, and medical checkups could have indirectly influenced their reluctance to withdraw from the study. CONCLUSION: Engagement meetings may increase the comprehension of informed consent among potential participants for HIV clinical trials. However, trial incentives may influence participation, and thus future research should focus on the challenges of giving incentives in the study. This will ensure comprehension and voluntary participation in the context of HIV clinical trials.

Vaccinating people living with HIV: a fast track to preventive and therapeutic HIV vaccines.

Globally, the number of new HIV infections remains unacceptably high, and urgent new approaches are needed to advance HIV vaccine science. However, the development of a preventive HIV vaccine has proven to be an intractable scientific challenge. Recent advances in HIV immunogen design have taken the field a step closer to triggering the rare precursors of broadly neutralising antibodies, which are widely assumed to be necessary for a vaccine. Nonetheless, these same studies and previous studies in people living with HIV have also highlighted the major hurdles that must be overcome to boost the cross-reactivity and potency of these responses to sufficient levels. Here, we describe an opportunity for fast-tracking the evaluation of candidate preventive and therapeutic vaccines by immunising people with HIV who are antiretroviral therapy suppressed. We argue that such studies, unlike traditional studies of vaccines in participants not infected with HIV, will be faster and more informative and will allow the vaccine field to bypass multiple hurdles. This approach will accelerate the process of defining the capacity of immunogens to trigger relevant antibodies, currently an extremely slow and expensive pathway, and provide a quick path to creating an HIV vaccine.

New HIV Vaccine Approach Safely Stimulated Rare Precursors to Broadly Neutralizing Antibodies.

This Medical News article discusses a clinical trial for an HIV vaccine that uses germline targeting, a novel technique to induce rare immune cell precursors of broadly neutralizing antibodies.

Examining oral pre-exposure prophylaxis (PrEP) literacy among participants in an HIV vaccine trial preparedness cohort study.

BACKGROUND: PrEP literacy is influenced by many factors including the types of information available and how it is interpreted. The level of PrEP literacy may influence acceptability and uptake. METHODS: We conducted 25 in-depth interviews in a HIV vaccine trial preparedness cohort study. We explored what participants knew about PrEP, sources of PrEP knowledge and how much they know about PrEP. We used the framework approach to generate themes for analysis guided by the Social Ecological Model and examined levels of PrEP literacy using the individual and interpersonal constructs of the SEM. RESULTS: We found that PrEP awareness is strongly influenced by external factors such as social media and how much participants know about HIV treatment and prevention in the local community. However, while participants highlighted the importance of the internet/social media as a source of information about PrEP they talked of low PrEP literacy in their communities. Participants indicated that their own knowledge came as a result of joining the HIV vaccine trial preparedness study. However, some expressed doubts about the effectiveness of the drug and worried about side effects. Participants commented that at the community level PrEP was associated with being sexually active, because it was used to prevent the sexual transmission of HIV. As a result, some participants commented that one could feel judged by the health workers for asking for PrEP at health facilities in the community. CONCLUSION: The information collected in this study provided an understanding of the different layers of influence around individuals that are important to address to improve PrEP acceptability and uptake. Our findings can inform strategies to address the barriers to PrEP uptake, particularly at structural and community levels. TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT04066881.

Challenges of HIV therapeutic vaccines clinical trials design.

PURPOSE OF THE REVIEW: To discuss main challenges of therapeutic vaccine clinical trials design, implementation and analyses in the HIV cure field. RECENT FINDINGS: Therapeutic vaccines are progressively being postulated as T-cell stimulating agents to use in combination HIV cure strategies, with the addition of immunomodulators, latency reversing agents and/or broadly neutralizing antibodies. Although promising strategies are rapidly evolving in preclinical studies using nonhuman primate models, translation into human testing in randomized controlled clinical trials is more challenging and expensive to conduct. Adaptive designs, access to cohorts of early-treated individuals, consensus on how to safely conduct analytical treatment interruptions, use of alternative statistical methods, development of point-of-care/home-based testing technologies and ensuring early engagement of communities where research is being developed are some of the critical aspects to consider to facilitate clinical trial development in the HIV cure field. SUMMARY: Design and development of HIV therapeutic vaccine clinical trials poses many challenges, from Phase 0/pilot studies to Phase I/II trials in which efficacy of the intervention is being tested and antiretroviral therapy cessation is needed, complexity of cure trials progressively increases. Understanding fundamental issues and careful planning of therapeutic vaccine clinical trials is crucial to minimize design flaws, reduce loss of follow-ups and missing data while ensuring participant's safety and guarantee valid and accurate analyses and thus, better contribute towards an HIV cure.

The Prevalence, Incidence, and Risk Factors for HIV Among Female Sex Workers-A Cohort Being Prepared for a Phase IIb HIV Vaccine Trial in Dar es Salaam, Tanzania.

BACKGROUND: A cohort of female sex workers (FSWs) was established to determine HIV prevalence and incidence, and associated factors in preparation for a phase IIb HIV vaccine and pre-exposure prophylaxis trial (PrEPVacc). SETTING: A cohort of FSWs in Dar es Salaam, Tanzania. METHODS: FSWs aged 18-45 years were recruited using a respondent-driven sampling method. Social demographic data, HIV risk behavioral assessments, and blood samples for testing of HIV, syphilis, hepatitis B (HBV), and hepatitis C (HCV) infections were collected at baseline and then at 3, 6, 9, and 12 months. Poisson regressions were used to estimate the prevalence ratios for factors associated with HIV prevalence and to estimate the 12-month HIV incidence rate. RESULTS: Between October and December 2018, a total of 773 FSWs were screened for eligibility and 700 were enrolled. The baseline prevalence of HIV, syphilis, HBV, and HCV was 7.6%, 1.2%, 1.7%, and 1.0%, respectively. HIV prevalence was associated with older age, using illicit drugs, and being infected with syphilis, HBV, or HCV. Attendance at 12 months was 80% (562/700). Twenty-one FSWs seroconverted during follow-up, giving a 12-month HIV incidence rate of 3.45 per 100 person-years at risk (95% CI; 2.25-5.28/100 person-years at risk). The HIV incidence rate was higher among FSWs aged 18-24 years, FSWs who used drugs, and those diagnosed with syphilis, HBV, or HCV. CONCLUSION: The high HIV incidence rate and retention rate among FSWs enrolled into the cohort demonstrate that this population is suitable for participation in HIV prevention trials.

Assessing acceptability of pre-exposure prophylaxis (PrEP) among participants in an HIV vaccine preparedness study in southwestern Uganda.

BACKGROUND: Daily oral pre-exposure prophylaxis (PrEP) use is highly effective against HIV infection. However, the uptake of PrEP among individuals at high-risk of HIV acquisition in sub-Saharan Africa varies because of availability and acceptability. We assessed the acceptability of PrEP among participants in a prospective HIV vaccine preparedness study in Masaka, southwestern Uganda. METHODS: From November 2018 to August 2019, 20 participants (10 female) were purposively selected for in-depth interviews (IDIs) at 3 and 9 months' post-enrolment in the vaccine preparedness study. Four focus group discussions (FGD) (two among men) were conducted with 29 individuals categorized as: younger (18-24 years) men, younger (18-24 years) women, older (≥30 years) men, and older (≥30 years) women. Apart from IDI specific questions on recent life history including work experience, relationship history and places lived, topics for IDIs and FGDs included knowledge of HIV, perceptions of HIV risk (including own risk), knowledge of and use of PrEP. The Theoretical Framework of Acceptability was used to structure a thematic framework approach for data analysis. RESULTS: Participants understood that PrEP was an oral pill taken daily by HIV negative individuals to prevent acquisition of HIV. Overall, interest in and acceptability of PrEP was high, more than half expressed positivity towards PrEP but were not ready to initiate taking it citing the burden of daily oral pill taking, related side effects, stigma and distrust of PrEP. Fourteen participants (from IDI and FGD) initiated PrEP, although some (one FGD and two IDI participants) stopped taking it due to side effects or perceived reduced risk. CONCLUSION: We observed a keen interest in PrEP initiation among our study participants. However, a limited understanding of PrEP and associated concerns impeded uptake and sustained use. Hence, interventions are needed to address end-user challenges to increase uptake and support adherence.

Predictors of Loss to Follow-Up in an HIV Vaccine Preparedness Study in Masaka, Uganda.

BACKGROUND: High participant retention is essential to achieve adequate statistical power for clinical trials. We assessed participant retention and predictors of loss to follow-up (LTFU) in an HIV vaccine-preparedness study in Masaka, Uganda. METHODS: Between July 2018 and March 2021, HIV sero-negative adults (18-45 years) at high risk of HIV infection were identified through HIV counselling and testing (HCT) from sex-work hotspots along the trans-African highway and fishing communities along the shores of Lake Victoria. Study procedures included collection of baseline socio-demographic data, quarterly HCT, and 6-monthly collection of sexual risk behaviour data. Retention strategies included collection of detailed locator data, short clinic visits (1-2 h), flexible reimbursement for transport costs, immediate (≤7 days) follow-up of missed visits via phone and/or home visits, and community engagement meetings. LTFU was defined as missing ≥2 sequential study visits. Poisson regression models were used to identify baseline factors associated with LTFU. RESULTS: 672 participants were included in this analysis. Of these, 336 (50%) were female and 390 (58%) were ≤24 years. The median follow-up time was 11 months (range: 0-31 months). A total 214 (32%) participants were LTFU over 607.8 person-years of observation (PYO), a rate of 35.2/100 PYO. LTFU was higher in younger participants (18-24 years versus 35-45 years, adjusted rate ratio (aRR) = 1.29, 95% confidence interval (CI) 0.80-2.11), although this difference was not significant. Female sex (aRR = 2.07, 95% CI, 1.51-2.84), and recreational drug use (aRR = 1.61, 95% CI, 1.12-2.34) were significantly associated with increased LTFU. Engagement in transactional sex was associated with increased LTFU (aRR = 1.36, 95% CI, 0.97-1.90) but this difference was not significant. LTFU was higher in 2020-2021 (the period of COVID-19 restrictions) compared to 2018-2019 (aRR = 1.54, 1.17-2.03). Being Muslim or other (aRR = 0.68, 95% CI 0.47-0.97) and self-identification as a sex worker (aRR = 0.47, 95% CI, 0.31-0.72) were associated with reduced LTFU. CONCLUSION: We observed a high LTFU rate in this cohort. LTFU was highest among women, younger persons, recreational drug users, and persons who engage in transactional sex. Efforts to design retention strategies should focus on these subpopulations.

The path towards an HIV vaccine.

Since the beginning of the HIV/AIDS epidemy in the eighties, hundreds of phase I human immunization studies were performed, however, only nine tested efficacy in phase IIb/III clinical trials. While immunogens for SARS-CoV-2 did move along the development and clinical trial pipeline at unprecedent speed, two HIV immunization vaccine trials, started in 2016 and 2017, did meet non-efficacy criteria at the interim analysis and were thus, halted by the Data and Safety Monitoring Boards. The challenges in the quest to develop a safe, effective and durable HIV vaccine are unchanged. However, as research on HIV vaccine discovery moves forward there are many new tools and platform technologies to iterate vaccine strategies faster. Among these, there is a growing interest to conduct experimental medicine approaches where product development is directly informed by human data at an early stage of product development.

Research progress on HIV-1 immune escape mechanisms.

Although highly active antiretroviral therapy has transformed HIV-1 infection into a manageable chronic disease, the development of an effective vaccine is still an important and challengeable research field of HIV-1 treatment. The challenge arises from an enormous diversity of HIV-1 strains and their rapid evolution ahead of effective immune responses. HIV-1 evasion from host immunity contributes to viral spread and pathogenesis, thus understanding the mechanisms of HIV-1 immune evasion is important. In this review, we summarized our present knowledge on the mechanisms how HIV-1 escapes immune responses. Such knowledge will help with the design of effective vaccines capable of inducing immune control of HIV-1.

"An Extra Variable to Consider"-Vaccine-Induced Seropositivity and Adolescent HIV Vaccine Clinical Trials.

Our study explores the understanding of vaccine-induced seropositivity (VISP) and its potential impact on US adolescents' and caregivers' willingness to participate in adolescent HIV vaccine clinical trials. Findings from in-depth interviews suggest that addressing concerns about VISP will be essential for future pediatric HIV vaccine trials in the United States.

Young at risk-people in Maputo City, Mozambique, present a high willingness to participate in HIV trials: Results from an HIV vaccine preparedness cohort study.

INTRODUCTION: Vaccine efficacy testing requires engagement of willing volunteers with high disease incidence. We evaluated factors associated with willingness to participate in potential future HIV vaccine trials in Maputo, Mozambique. METHODS: Adults aged 18-35 years without HIV and who reported at least two sexual partners in the 3 months prior to screening were enrolled into a 24-month observational study. They were asked at screening and exit if they would be willing to participate in a theoretical HIV vaccine study. Bivariate and multivariate logistic regression analyses were done between willingness to participate, demographic, sexual behavior, and motivational factors for screening visit data. Logistic regression with generalized estimating equations (GEE) was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for factors potentially associated with willingness to participate for data from both visits. RESULTS: A total of 577 participants without HIV were eligible, including 275 (48%) women. The mean age was 22.2 (SD ± 3.9) years. At screening 529 (92%) expressed willingness to participate and the proportion remained stable at 378 (88%) of the 430 participants retained through the exit visit (p = 0.209). Helping the country (n = 556) and fear of needles (n = 26) were the top motive and barrier for willingness to participate, respectively. Results from the GEE binary logistic regression (screening visit and exit visit) showed that wanting to learn how to avoid risk behaviors (aOR 3.33, 95% CI: 1.61-6.86) and feeling protected against HIV infection (aOR 2.24, 95% CI: 1.07-4.7) were associated with willingness to participate in HIV vaccine studies. CONCLUSION: The majority of our study population in Mozambique expressed willingness to participate in a theoretical HIV vaccine trial. Participation in a HIV vaccine trial was seen as a way to contribute to the fight against HIV but was associated with some unrealistic expectations such as protection against HIV. This reinforces the need for continuous mobilization and awareness of potential participants to HIV vaccine trial.

A site of vulnerability at V3 crown defined by HIV-1 bNAb M4008_N1.

Identification of vulnerable sites defined by broadly neutralizing antibodies (bNAbs) on HIV-1 envelope (Env) is crucial for vaccine design, and we present here a vulnerable site defined by bNAb M4008_N1, which neutralizes about 40% of a tier-2 virus panel. A 3.2 Å resolution cryo-EM structure of M4008_N1 in complex with BG505 DS-SOSIP reveals a large, shallow protein epitope surface centered at the V3 crown of gp120 and surrounded by key glycans. M4008_N1 interacts with gp120 primarily through its hammerhead CDR H3 to form a ß-sheet interaction with the V3 crown hairpin. This makes M4008_N1 compatible with the closed conformation of the prefusion Env trimer, and thus distinct from other known V3 crown mAbs. This mode of bNAb approaching the immunogenic V3 crown in the native Env trimer suggests a strategy for immunogen design targeting this site of vulnerability.

Chemoenzymatic Synthesis and Antibody Binding of HIV-1 V1/V2 Glycopeptide-Bacteriophage Qß Conjugates as a Vaccine Candidate.

The broadly neutralizing antibody PG9 recognizes a unique glycopeptide epitope in the V1V2 domain of HIV-1 gp120 envelope glycoprotein. The present study describes the design, synthesis, and antibody-binding analysis of HIV-1 V1V2 glycopeptide-Qß conjugates as a mimic of the proposed neutralizing epitope of PG9. The glycopeptides were synthesized using a highly efficient chemoenzymatic method. The alkyne-tagged glycopeptides were then conjugated to the recombinant bacteriophage (Qß), a virus-like nanoparticle, through a click reaction. Antibody-binding analysis indicated that the synthetic glycoconjugates showed significantly enhanced affinity for antibody PG9 compared with the monomeric glycopeptides. It was also shown that the affinity of the Qß-conjugates for antibody PG9 was dependent on the density of the glycopeptide antigen display. The glycopeptide-Qß conjugates synthesized represent a promising candidate of HIV-1 vaccine.

Monocyte-derived transcriptome signature indicates antibody-dependent cellular phagocytosis as a potential mechanism of vaccine-induced protection against HIV-1.

A gene signature was previously found to be correlated with mosaic adenovirus 26 vaccine protection in simian immunodeficiency virus and simian-human immunodeficiency virus challenge models in non-human primates. In this report, we investigated the presence of this signature as a correlate of reduced risk in human clinical trials and potential mechanisms of protection. The absence of this gene signature in the DNA/rAd5 human vaccine trial, which did not show efficacy, strengthens our hypothesis that this signature is only enriched in studies that demonstrated protection. This gene signature was enriched in the partially effective RV144 human trial that administered the ALVAC/protein vaccine, and we find that the signature associates with both decreased risk of HIV-1 acquisition and increased vaccine efficacy (VE). Total RNA-seq in a clinical trial that used the same vaccine regimen as the RV144 HIV vaccine implicated antibody-dependent cellular phagocytosis (ADCP) as a potential mechanism of vaccine protection. CITE-seq profiling of 53 surface markers and transcriptomes of 53,777 single cells from the same trial showed that genes in this signature were primarily expressed in cells belonging to the myeloid lineage, including monocytes, which are major effector cells for ADCP. The consistent association of this transcriptome signature with VE represents a tool both to identify potential mechanisms, as with ADCP here, and to screen novel approaches to accelerate the development of new vaccine candidates.

A retrospective analysis of incident pregnancy in phase 1 and 2a HIV-1 vaccine study participants does not support concern for adverse pregnancy or birth outcomes.

BACKGROUND: Pregnancies occur during HIV-1 vaccine clinical trials, despite requirements for women of reproductive potential to use effective contraception. Deployment of an effective HIV-1 vaccine regimen will likely target adolescents and young adults and therefore safety for pregnant and breastfeeding women will need to be addressed. METHODS: We performed a retrospective, cross-protocol analysis to identify and compare pregnancy outcomes reported in 53 Phase 1 and Phase 2a HIV-1 vaccine clinical trials conducted by the HIV Vaccine Trials Network (HVTN). RESULTS: Two thousand six hundred seventy-three women of reproductive potential were identified and 193 pregnancies were reported. 39 of 53 (74%) studies had at least one pregnancy reported with an overall pregnancy rate of 3.15 per 100 woman-years (w-yr). While active contraception use was required during study participation, 13 of the 53 studies also contained a long-term follow up period during which pregnancy was no longer discouraged. The pregnancy rate during main study participation was 3.09 per 100 w-yr, while pregnancies occurred at a slightly greater rate in the long-term follow up period (3.22 per 100 w-yr). Adverse pregnancy outcomes were reported at similar rates between vaccinees and placebo recipients when vaccine vectors, adjuvant used, or geographic region were examined. CONCLUSION: Although there is considerable heterogeneity amongst the different vaccine trials, there appears to be no obvious indication of increased risk of adverse pregnancy or birth outcomes in these early phase HIV-1 vaccine studies. More complete data on pregnancy outcomes should be collected in early phase HIV-1 vaccine clinical trials to better inform subsequent efficacy trials.

Levels of vaccination coverage among HIV-exposed children in China: a retrospective study.

BACKGROUND: Vaccination is crucial for human immunodeficiency virus (HIV)-exposed children because of their increased risk of morbidity and mortality from various vaccine-preventable diseases. However, studies have shown that they are at high risk of incomplete vaccination. Although China has developed prevention of mother-to-child transmission (PMTCT) of HIV programs substantially over the past decades, few studies have investigated the immunization levels of Chinese HIV-exposed children. Therefore, we aimed to evaluate vaccination coverage and its associated factors among HIV-exposed children in China during 2016‒2018. METHODS: We conducted a retrospective cohort review of all cases of Chinese HIV-exposed children born between July 1, 2016 and June 30, 2018 recorded in the Chinese information system on PMTCT. The vaccination coverage indicators refer to the percentage of children who received recommended basic vaccines, including Bacillus Calmette-Guérin (BCG), hepatitis B (HepB), polio, measles-containing vaccine (MCV), and diphtheria-tetanus-pertussis-containing (DTP) vaccine. Univariate and multivariate logistic regression analyses expressed as crude odds ratios (cORs) and adjusted odds ratios (aORs), each with 95% confidence intervals (95% CI), were performed to compare the proportional differences of factors associated with vaccine coverage. RESULTS: Among the enrolled 10 033 children, the vaccination rate was 54.1% for BCG, 84.5% for complete HepB vaccination, 54.5% for complete polio vaccination, 51.3% for MCV, and 59.5% for complete DTP vaccination. Children with perinatally acquired HIV (PHIV) were 2.46‒3.82 times less likely to be vaccinated than HIV-exposed uninfected children. Multivariate logistic regression indicated that children of Han ethnicity (aOR = 1.33‒2.04), children with early infant diagnosis (EID) of HIV (aOR = 1.86‒3.17), and children whose mothers had better education (college or above, aOR = 1.63‒2.51) had higher odds of being vaccinated. Most of the deceased children (aOR = 4.28‒21.55) missed vaccination, and PHIV (aOR = 2.46‒3.82) significantly affected immunization. CONCLUSIONS: Chinese HIV-exposed children had low vaccination coverage, which is a serious health challenge that needs to be addressed thoroughly. Interventions should be developed with a focus on minority HIV-exposed children whose mothers do not have formal education. Particularly, more attention should be paid to EID to increase access to immunization.

Coming together at the hinges: Therapeutic prospects of IgG3.

The human IgG3 subclass is conspicuously absent among the formats for approved monoclonal antibody therapies and Fc fusion protein biologics. Concern about the potential for rapid degradation, reduced plasma half-life, and increased immunogenicity due to marked variation in allotypes has apparently outweighed the potential advantages of IgG3, which include high affinity for activating Fcγ receptors, effective complement fixation, and a long hinge that appears better suited for low abundance targets. This review aims to highlight distinguishing features of IgG3 and to explore its functional role in the immune response. We present studies of natural immunity and recombinant antibody therapies that elucidate key contributions of IgG3 and discuss historical roadblocks that no longer remain clearly relevant. Collectively, this body of evidence motivates thoughtful reconsideration of the clinical advancement of this distinctive antibody subclass for treatment of human diseases. Abbreviations: ADCC - Antibody-Dependent Cell-mediated CytotoxicityADE - Antibody-dependent enhancementAID - Activation-Induced Cytidine DeaminaseCH - Constant HeavyCHF - Complement factor HCSR - Class Switch RecombinationEM - Electron MicroscopyFab - Fragment, antigen bindingFc - Fragment, crystallizableFcRn - Neonatal Fc ReceptorFcγR - Fc gamma ReceptorHIV - Human Immunodeficiency VirusIg - ImmunoglobulinIgH - Immunoglobulin Heavy chain geneNHP - Non-Human Primate.

A Phase 2b Study to Evaluate the Safety and Efficacy of VRC01 Broadly Neutralizing Monoclonal Antibody in Reducing Acquisition of HIV-1 Infection in Women in Sub-Saharan Africa: Baseline Findings.

BACKGROUND: HIV Vaccine Trials Network 703/HIV Prevention Trials Network 081 is a phase 2b randomized, double-blind, placebo-controlled trial to assess the safety and efficacy of passively infused monoclonal antibody VRC01 in preventing HIV acquisition in heterosexual women between the ages of 18 and 50 years at risk of HIV. Participants were enrolled at 20 sites in Botswana, Kenya, Malawi, Mozambique, South Africa, Tanzania, and Zimbabwe. It is one of the 2 Antibody Mediated Prevention efficacy trials, with HIV Vaccine Trials Network 704/HIV Prevention Trials Network 085, evaluating VRC01 for HIV prevention. METHODS: Intense community engagement was used to optimize participant recruitment and retention. Participants were randomly assigned to receive intravenous VRC01 10 mg/kg, VRC01 30 mg/kg, or placebo in a 1:1:1 ratio. Infusions were given every 8 weeks with a total of 10 infusions and 104 weeks of follow-up after the first infusion. RESULTS: Between May 2016 and September 2018, 1924 women from sub-Saharan Africa were enrolled. The median age was 26 years (interquartile range: 22-30), and 98.9% were Black. Sexually transmitted infection prevalence at enrollment included chlamydia (16.9%), trichomonas (7.2%), gonorrhea (5.7%), and syphilis (2.2%). External condoms (83.2%) and injectable contraceptives (61.1%) were the methods of contraception most frequently used by participants. In total, through April 3, 2020, 38,490 clinic visits were completed with a retention rate of 96% and 16,807 infusions administered with an adherence rate of 98%. CONCLUSIONS: This proof-of-concept, large-scale monoclonal antibody study demonstrates the feasibility of conducting complex trials involving intravenous infusions in high incidence populations in sub-Saharan Africa.