Scientific Publications

Background
Adolescent girls and young women (AGYW), aged 15–24 years, are disproportionately affected by HIV and other sexual and reproductive health (SRH) risks due to varying social, cultural, and economic factors that affect their choices and shape their knowledge, understanding, and practices with regard to their health. Socio‐Behavioral Change Communication (SBCC) interventions targeted at strengthening the capabilities of individuals and their networks have supported the demand and uptake of prevention services and participation in biomedical research. However, despite growing global recognition of the domain, high‐quality evidence on the effectiveness of SBCC remains scattered. This evidence and gap map (EGM) report characterizes the evidence base on SBCC interventions for strengthening HIV Prevention and Research among AGYW in low‐ and middle‐income countries (LMICs), identifying evidence gaps and outlining the scope of future research and program design.

Objectives
The objectives of the proposed EGM are to: (a) identify and map existing EGMs in the use of diverse SBCC strategies to strengthen the adoption of HIV prevention measures and participation in research among AGYW in LMICs and (b) identify areas where more interventions and evidence are needed to inform the design of future SBCC strategies and programs for AGYW engagement in HIV prevention and research.

Methods
This EGM is based on a comprehensive search of systematic reviews and impact evaluations corresponding to a range of interventions and outcomes—aimed at engaging AGYW in HIV prevention and research ‐ that were published in LMICs from January 2000 to April 2021. Based on guidance for producing a Campbell Collaboration EGM, the intervention and outcome framework was designed in consultation with a group of experts. These interventions were categorized across four broad intervention themes: mass‐media, community‐based, interpersonal, and Information Communication and Technology (ICT)/Digital Media‐based interventions. They were further sub‐categorized into 15 intervention categories. Included studies looked at 23 unique behavioral and health outcomes such as knowledge attitude and skills, relationship dynamics, household dynamics, health care services, and health outcomes and research engagement. The EGM is presented as a matrix in which the rows are intervention categories/sub‐categories, and the columns are outcome domains/subdomains. Each cell is mapped to an intervention targeted at outcomes. Additional filters like region, country, study design, age group, funding agency, influencers, population group, publication status, study confidence, setting, and year of publication have been added.

Selection Criteria
To be eligible, studies must have tested the effectiveness of SBCC interventions at engaging AGYW in LMICs in HIV prevention and research. The study sample must have consisted of AGYW between the ages of 15–24, as defined by UNAIDS. Both experimental (random assignment) and quasi‐experimental studies that included a comparison group were eligible. Relevant outcomes included those at the individual, influencer, and institutional levels, along with those targeting research engagement and prevention‐related outcomes.

Results
This EGM comprises 415 impact evaluations and 43 systematic reviews. Interventions like peer‐led interactions, counseling, and community dialogues were the most dominant intervention sub‐types. Despite increased digital penetration use of media and technology‐driven interventions are relatively less studied. Most of the interventions were delivered by peers, health care providers, and educators, largely in school‐based settings, and in many cases are part of sex‐education curricula. Evidence across geographies was mostly concentrated in Sub‐Saharan Africa (70%). Most measured outcomes focused on disease‐related knowledge dissemination and enhancing awareness of available prevention options/strategies. These included messaging around consistent condom use, limiting sexual partners, routine testing, and awareness. Very few studies were able to include psychographic, social, and contextual factors influencing AGYW health behaviors and decisions, especially those measuring the impact of social and gender norms, relationship dynamics, and household dynamics‐related outcomes. Outcomes related to engagement in the research were least studied.

Conclusion
This EGM highlights that evidence is heavily concentrated within the awareness‐intent spectrum of behavior change and gets lean for outcomes situated within the intent‐action and the action‐habit formation spectrum of the behavior change continuum. Most of the evidence was concentrated on increasing awareness, knowledge, and building risk perception around SRH domains, however, fewer studies focused on strengthening the agency and self‐efficacy of individuals. Similarly, evidence on extrinsic factors—such as strengthening social and community norms, relationships, and household dynamics—that determine individual thought and action such as negotiation and life skills were also found to be less populated. Few studies explore the effectiveness of these interventions across diverse AGYW identities, like pregnant women and new mothers, sex workers, and people living with HIV, leading to limited understanding of the use of these interventions across multiple user segments including key influencers such as young men, partners, families, religious leaders, and community elders was relatively low. There is a need for better quality evidence that accounts for the diversity of experiences within these populations to understand what interventions work, for whom, and toward what outcome. Further, the evidence for use of digital and mass‐media tools remains poorly populated. Given the increasing penetration of these tools and growing media literacy on one end, with widening gender‐based gaps on the other, it is imperative to gather more high‐quality evidence on their effectiveness. Timely evidence generation can help leverage these platforms appropriately and enable intervention designs that are responsive to changing communication ecologies of AGYW. SBCC can play a critical role in helping researchers meaningfully engage and collaborate with communities as equal stakeholders, however, this remains poorly evidenced and calls for investigation and investment. A full list of abbreviations and acronyms are available in Supporting Information: Appendix F.

A prophylactic vaccine is needed to slow the spread of HIV-1 infection. Optimization of the wild-type envelope glycoproteins to create immunogens that can elicit effective neutralizing antibodies is a high priority. Starting with ten genes encoding subtype B HIV-1 gp120 envelope glycoproteins and using in vitro homologous DNA recombination, we created chimeric gp120 variants that were screened for their ability to bind neutralizing monoclonal antibodies. Hundreds of variants were identified with novel antigenic phenotypes that exhibit considerable sequence diversity. Immunization of rabbits with these gp120 variants demonstrated that the majority can induce neutralizing antibodies to HIV-1. One novel variant, called ST-008, induced significantly improved neutralizing antibody responses when assayed against a large panel of primary HIV-1 isolates. Further study of various deletion constructs of ST-008 showed that the enhanced immunogenicity results from a combination of effective DNA priming, an enhanced V3-based response, and an improved response to the constant backbone sequences.

Background
Population mobility is a demonstrated barrier to reducing HIV incidence. A clear understanding of social networks and their influence on mobility among women in the fishing communities of Lake Victoria may contribute to tailoring effective interventions that suit the needs of these mobile women.

Methods
A cross-sectional qualitative methods study was conducted to understand mobility patterns among women resident and or working in fishing communities of Lake Victoria in Kenya, Tanzania, and Uganda. The study was conducted in six fishing communities from March 2018 to June 2019. The communities were purposively selected, based on population size (1000 people or more) and HIV prevalence of > 15% among women aged 18 years or older who had lived in the fishing community for at least six months. In-depth interviews were conducted with 24 key informants and 72 women from the sites in the three countries. Questions focused on women’s social networks and other factors that fuelled or facilitated women’s mobility as well as challenges they faced due to mobility. Data analysis followed a thematic framework approach.

Results
Different social groupings/networks existed among women in the fishing communities of Lake Victoria. These included female sex workers, women fish processors/traders, women bar workers/owners, restaurant workers, and family networks. Networks encouraged mobility, supporting finding work opportunities, but also increased sexual risks through partner changes. The benefits of networks included information sharing, financial support, and group protection, especially against violence.

Conclusion
Social networks and groupings among women in the fishing communities of Lake Victoria could be useful in tailoring HIV prevention and HIV care interventions to suit the needs of these highly mobile populations.

Antibody heavy chain (HC) and light chain (LC) variable region exons are assembled by V(D)J recombination. V(D)J junctional regions encode complementarity-determining-region 3 (CDR3), an antigen-contact region immensely diversified through nontemplated nucleotide additions (“N-regions”) by terminal deoxynucleotidyl transferase (TdT). HIV-1 vaccine strategies seek to elicit human HIV-1 broadly neutralizing antibodies (bnAbs), such as the potent CD4-binding site VRC01-class bnAbs. Mice with primary B cells that express receptors (BCRs) representing bnAb precursors are used as vaccination models. VRC01-class bnAbs uniformly use human HC VH1-2 and commonly use human LCs Vκ3-20 or Vκ1-33 associated with an exceptionally short 5-amino-acid (5-aa) CDR3. Prior VRC01-class models had nonphysiological precursor levels and/or limited precursor diversity. Here, we describe VRC01-class rearranging mice that generate more physiological primary VRC01-class BCR repertoires via rearrangement of VH1-2, as well as Vκ1-33 and/or Vκ3-20 in association with diverse CDR3s. Human-like TdT expression in mouse precursor B cells increased LC CDR3 length and diversity and also promoted the generation of shorter LC CDR3s via N-region suppression of dominant microhomology-mediated Vκ-to-Jκ joins. Priming immunization with eOD-GT8 60mer, which strongly engages VRC01 precursors, induced robust VRC01-class germinal center B cell responses. Vκ3-20-based responses were enhanced by N-region addition, which generates Vκ3-20-to-Jκ junctional sequence combinations that encode VRC01-class 5-aa CDR3s with a critical E residue. VRC01-class-rearranging models should facilitate further evaluation of VRC01-class prime and boost immunogens. These new VRC01-class mouse models establish a prototype for the generation of vaccine-testing mouse models for other HIV-1 bnAb lineages that employ different HC or LC Vs.

Objective
To assess the feasibility of conducting HIV prevention trials among key populations in Nairobi, Kenya.

Background
HIV prevention trials require the inclusion of those at high risk of HIV infection and their informed decision to take part and remain in the clinical trial to the end is crucial. In Kenya key populations including men who have sex with men (MSM) and female sex workers (FSW) are, disproportionately, at high risk of HIV infection when compared to the general population. Few trials testing biomedical prevention products against HIV have enrolled Kenyan FSW and MSM.

Methods
We performed simulated vaccine efficacy trial (SiVET) using licensed hepatitis B vaccines as substitutes for a HIV vaccine candidate and included randomization for those immune to hep B. The SiVET was an observational study designed to mimic the rigors of a clinical trial; we assessed HIV risk, provided risk counselling and prevention tools and performed HIV testing at baseline and periodically until the end of the trial. MSM and FSW were enrolled at a ratio of 4:1. Volunteers were assigned to either hepatitis B vaccine or placebo.

Results
Recruitment took approximately 24 months between Sep 2015 and Sep 2017. Of the 368 volunteers screened, 250 (200 MSM and 50 FSW) were enrolled. Reasons for exclusion at screening included: being positive for HIV (n = 7), hepatitis (n = 14), other pre-existing medical conditions (n = 41), eligible but chose not to enrol (n = 47). Most of the volunteers adhered to study procedures and attended their study visits within the study window. These include volunteers who received the second vaccination 244 (98%), the third vaccination 228 (91%) and, the final study visit 217 (87%). The reasons volunteers discontinued from the study early included: relocation and loss to follow up (n = 14). A total of 8 cases of HIV infection were observed in 174.5 Person Years at Risk (PYAR), all among MSM, including 5 seroconversions identified at the last study visit, for a HIV incidence of 4.58 cases/ 100 PYAR, among MSM enrolled in the study.

Conclusion
Our findings suggest that it is possible to conduct HIV prevention trials among key populations in Nairobi with a good adherence to a vaccine efficacy trial schedule. Despite HIV prevention efforts, we also noted a high incidence of HIV infection. This demonstrates the need for effective HIV prevention products in these populations.

Broadly neutralizing antibodies (bnAbs) can protect against HIV infection but have not been induced by human vaccination. A key barrier to bnAb induction is vaccine priming of rare bnAb-precursor B cells. In a randomized, double-blind, placebo-controlled phase 1 clinical trial, the HIV vaccine-priming candidate eOD-GT8 60mer adjuvanted with AS01B had a favorable safety profile and induced VRC01-class bnAb precursors in 97% of vaccine recipients with median frequencies reaching 0.1% among immunoglobulin G B cells in blood. bnAb precursors shared properties with bnAbs and gained somatic hypermutation and affinity with the boost. The results establish clinical proof of concept for germline-targeting vaccine priming, support development of boosting regimens to induce bnAbs, and encourage application of the germline-targeting strategy to other targets in HIV and other pathogens.

Introduction
Immunological protection against human immunodeficiency virus-1 (HIV-1) infection is likely to require both humoral and cell-mediated immune responses, the latter involving cytotoxic CD8 T-cells. Characterisation of CD8 T-cell mediated direct anti-viral activity would provide understanding of potential correlates of immune protection and identification of critical epitopes associated with HIV-1 control.

Methods
The present report describes a functional viral inhibition assay (VIA) to assess CD8 T-cell-mediated inhibition of replication of a large and diverse panel of 45 HIV-1 infectious molecular clones (IMC) engineered with a Renilla reniformis luciferase reporter gene (LucR), referred to as IMC-LucR. HIV-1 IMC replication in CD4 T-cells and CD8 T-cell mediated inhibition was characterised in both ART naive subjects living with HIV-1 covering a broad human leukocyte antigen (HLA) distribution and compared with uninfected subjects.

Results & discussion
CD4 and CD8 T-cell lines were established from subjects vaccinated with a candidate HIV-1 vaccine and provided standard positive controls for both assay quality control and facilitating training and technology transfer. The assay was successfully established across 3 clinical research centres in Kenya, Uganda and the United Kingdom and shown to be reproducible. This IMC-LucR VIA enables characterisation of functional CD8 T-cell responses providing a tool for rational T-cell immunogen design of HIV-1 vaccine candidates and evaluation of vaccine-induced T-cell responses in HIV-1 clinical trials.

Region-specific laboratory reference intervals (RIs) are important for clinical trials and these data are often sparse in priority areas for research, including Africa. We reviewed data on RIs from Africa to identify gaps in the literature with a systematic review of PubMed for RI studies from Africa published ≥2010. Search focus included clinical analytic chemistry, hematology, immunological parameters and RIs. Data from adults, adolescents, children, pregnant women, and the elderly were included. We excluded manuscripts reporting data from persons with conditions that might preclude clinical trial participation in studies enrolling healthy volunteers. Of 179 identified manuscripts, 80 were included in this review, covering 20 countries with the largest number of studies in Ethiopia (n = 23, 29%). Most studies considered healthy, nonpregnant adults (n = 55, 69%). Nine (11%) studies included pregnant women, 13 (16%) included adolescents and 22 (28%) included children. Recruitment, screening, enrollment procedures and definition of age strata varied across studies. The most common type of RIs reported were hematology (66, 83%); 14 studies (18%) included flow cytometry and/or T cell counts. Other common tests or panels included liver function assays (32, 40%), renal function assays (30, 38%), lipid chemistries (17, 21%) and serum electrolytes (17, 21%). The number of parameters characterized ranged from only one (three studies characterized either CD4+ counts, D-dimer, or hemoglobin), to as many as 40. Statistical methods for calculating RIs varied. 56 (70%) studies compared their results to international RI databases. Though most presented their data side-by-side with international data with little accompanying analysis, nearly all reported deviation from comparator RI data, sometimes with half or more of otherwise healthy participants having an “out of range” result. We found there is limited local RI data available in sub-Saharan Africa. Studies to fill this gap are warranted, including efforts to standardize statistical methods to derive RIs, methods to compare with other RIs, and improve representative participant selection.

Background
There is limited information on factors that influence oral pre-exposure prophylaxis (PrEP) uptake and adherence among adolescent girls and young women (AGYW). We conducted a qualitative methods study to explore experiences, facilitators and barriers of PrEP uptake and adherence to PrEP among AGYW at risk of Human Immunodeficiency Virus (HIV) infection in Kampala, Uganda.

Methods
This study was nested in a prospective cohort study that offered daily oral PrEP to AGYW. Between April 2019 and October 2020 we conducted in-depth interviews with 26 AGYW aged 14–24 years who had been offered or had been using PrEP for at least 6 months, including PrEP adherers (8), non-adherers (8) and those who had declined PrEP (10). After 12 months, follow-up interviews were conducted with 12 AGYW who had adhered to PrEP and those who had dropped it. Thematic analysis was conducted and data were further examined and categorized into the 5 constructs of the Socio-Ecological Model (SEM).

Results
PrEP uptake and adherence were facilitated by factors including: perceptions that one’s own or partner’s sexual behaviour was high risk, a negative attitude towards condoms, social support and wanting to maintain a negative HIV status after receiving a negative HIV test result. Good adherence to PrEP was enabled by effective counselling, support tools such as alarms and phone reminders and incentives like free treatment for STIs and other illnesses during study visits. Barriers to uptake included: anxiety about the pill burden, perceptions of being too young for PrEP and fear of being labelled `prostitute’ or `HIV positive’. Poor adherence was attributed to doubt over the efficacy of PrEP as a result of beliefs that because HIV was incurable, no medicine could prevent it. Alcohol use, side effects experienced, and mobility all had a negative impact on adherence. The majority of PrEP users reported feeling safe as a result of using PrEP which had both good and negative implications on their sexual behaviour, specifically the number of sexual partners and condom use.

Conclusion
Addressing community misconceptions to maximize uptake of PrEP among AGYW is important. Targeted education messages, and counselling to address misconceptions in ways that capture the attention of AGYW in communities are required.

Broadly neutralizing antibodies (bnAbs) to the HIV envelope (Env) V2-apex region are important leads for HIV vaccine design. Most V2-apex bnAbs engage Env with an uncommonly long heavy-chain complementarity-determining region 3 (HCDR3), suggesting that the rarity of bnAb precursors poses a challenge for vaccine priming. We created precursor sequence definitions for V2-apex HCDR3-dependent bnAbs and searched for related precursors in human antibody heavy-chain ultradeep sequencing data from 14 HIV-unexposed donors. We found potential precursors in a majority of donors for only two long-HCDR3 V2-apex bnAbs, PCT64 and PG9, identifying these bnAbs as priority vaccine targets. We then engineered ApexGT Env trimers that bound inferred germlines for PCT64 and PG9 and had higher affinities for bnAbs, determined cryo-EM structures of ApexGT trimers complexed with inferred-germline and bnAb forms of PCT64 and PG9, and developed an mRNA-encoded cell-surface ApexGT trimer. These methods and immunogens have promise to assist HIV vaccine development.

Eliciting broadly neutralizing antibodies (bnAbs) is the core of HIV vaccine design. bnAbs specific to the V2-apex region of the HIV envelope acquire breadth and potency with modest somatic hypermutation, making them attractive vaccination targets. To evaluate Apex germline-targeting (ApexGT) vaccine candidates, we engineered knockin (KI) mouse models expressing the germline B cell receptor (BCR) of the bnAb PCT64. We found that high affinity of the ApexGT immunogen for PCT64-germline BCRs was necessary to specifically activate KI B cells at human physiological frequencies, recruit them to germinal centers, and select for mature bnAb mutations. Relative to protein, mRNA-encoded membrane-bound ApexGT immunization significantly increased activation and recruitment of PCT64 precursors to germinal centers and lowered their affinity threshold. We have thus developed additional models for HIV vaccine research, validated ApexGT immunogens for priming V2-apex bnAb precursors, and identified mRNA-LNP as a suitable approach to substantially improve the B cell response.

The emergence of Marburg virus (MARV) in Guinea and Ghana triggered the assembly of the MARV vaccine “MARVAC” consortium representing leaders in the field of vaccine research and development aiming to facilitate a rapid response to this infectious disease threat. Here, we discuss current progress, challenges, and future directions for MARV vaccines.

Vaccines generate high-affinity antibodies by recruiting antigen-specific B cells to germinal centers (GCs), but the mechanisms governing the recruitment to GCs on secondary challenges remain unclear. Here, using preclinical SARS-CoV and HIV mouse models, we demonstrated that the antibodies elicited during primary humoral responses shaped the naive B cell recruitment to GCs during secondary exposures. The antibodies from primary responses could either enhance or, conversely, restrict the GC participation of naive B cells: broad-binding, low-affinity, and low-titer antibodies enhanced recruitment, whereas, by contrast, the high titers of high-affinity, mono-epitope-specific antibodies attenuated cognate naive B cell recruitment. Thus, the directionality and intensity of that effect was determined by antibody concentration, affinity, and epitope specificity. Circulating antibodies can, therefore, be important determinants of antigen immunogenicity. Future vaccines may need to overcome—or could, alternatively, leverage—the effects of circulating primary antibodies on subsequent naive B cell recruitment.