HIV vaccine-induced sero-reactivity: a challenge for trial participants, researchers, and physicians

Perceptions and Acceptance of a Prophylactic Vaccine for Human Immunodeficiency Virus (HIV): A Qualitative Study

BACKGROUND

Despite advances in human immunodeficiency virus (HIV) prevention methods, such as the advent of pre-exposure prophylaxis (PrEP), the number of people with newly acquired HIV remains high, particularly in at-risk groups. A prophylactic HIV vaccine could contribute to reduced disease prevalence and future transmission and address limitations of existing options, such as suboptimal long-term adherence to PrEPs.

METHODS

This qualitative study aimed to capture perceptions towards and acceptance of prophylactic HIV vaccination in three adult populations in the United States: the general population, 'at-risk' individuals (e.g. men who have sex with men, transgender individuals, gender-nonconforming individuals, and individuals in a sexual relationship with a person living with HIV), and parents/caregivers of children aged 9-17 years. Interviews were conducted with 55 participants to explore key drivers and barriers to HIV vaccine uptake, and a conceptual model was developed.

RESULTS

The sample was diverse; participants were 51% female, aged 20-57 years (mean 37 years), 33% with high school diploma as highest education level, and identified as White (42%), Black or African American (35%), of Hispanic, Latino, or Spanish origin (22%), or other races/ethnicities (8%) [groupings are not mutually exclusive]. Perceptions were influenced by individual, interpersonal, community, institutional, and structural factors. Overall, 98% of participants thought vaccination would be beneficial in preventing HIV. Key considerations/barriers included perceived susceptibility, i.e. whether participants felt there was a risk of contracting HIV (discussed by 90%); the clinical profile of the vaccine (e.g. the adverse effect profile [98%], and vaccine efficacy [85%], cost [73%] and administration schedule [88%]); and concerns around potential vaccine-induced seropositivity (VISP; 62%). Stigma was not found to be an important barrier, with a general view that vaccination status was personal. Participants in the 'at-risk' group were the most likely to accept an HIV vaccine (70%). Unique concerns in the subgroups included how a potential vaccine's clinical profile compared with PrEP, voiced by those receiving/considering PrEP, and considerations of children's views on the topic, voiced by parents/caregivers.

CONCLUSIONS

Understanding these factors could help develop HIV vaccine research strategies and contribute toward public health messaging to support future HIV vaccination programs.

HIV Diagnostics and Vaccines: It Takes Two to Tango

Current serologic tests for HIV screening and confirmation of infection present challenges to the adoption of HIV vaccines. The detection of vaccine-induced HIV-1 antibodies in the absence of HIV-1 infection, referred to as vaccine-induced seropositivity/seroreactivity, confounds the interpretation of test results, causing misclassification of HIV-1 status with potential affiliated stigmatization. For HIV vaccines to be widely adopted with high community confidence and uptake, tests are needed that are agnostic to the vaccination status of tested individuals (ie, positive only for true HIV-1 infection). Successful development and deployment of such tests will require HIV vaccine developers to work in concert with diagnostic developers. Such tests will need to match today's high-performance standards (accuracy, cost-effectiveness, simplicity) for use in vaccinated and unvaccinated populations, especially in low- and middle-income countries with high HIV burden. Herein, we discuss the challenges and strategies for developing modified serologic HIV tests for concurrent deployment with HIV vaccines.

Safety and immunogenicity of a recombinant oligomeric gp145 subtype C Env protein (gp145 C.6980) HIV vaccine candidate in healthy, HIV-1-uninfected adult participants in the US

BACKGROUND

An approach to a preventive HIV vaccine is induction of effective broadly neutralizing antibodies (bnAbs) and effector binding antibodies (bAbs). Preclinical studies suggest that trimeric envelope (Env) proteins may elicit nAbs, which led to the development of the recombinant gp145 subtype C Env protein (gp145 C.6980) immunogen. HVTN 122 was a Phase 1 trial that evaluated the safety, tolerability, and immunogenicity of gp145 C.6980 in adults.

METHODS

Healthy, HIV-1 seronegative adults received three intramuscular injections of gp145 C.6980 with aluminum hydroxide (alum) at months 0, 2, and 6 at either 300 mcg (high dose, n = 25) or 100 mcg (low dose, n = 15), or placebo/saline (placebo, n = 5). Participants were followed for 12 months.

RESULTS

Forty-five participants were enrolled. High and low doses of the study protein were well-tolerated, with mild or moderate reactogenicity commonly reported. Only one adverse event (mild injection site pruritis) in one participant (low dose) was considered product-related; there were no dose-limiting toxicities. High and low dose recipients demonstrated robust bAb responses to vaccine-matched consensus gp140 Env and subtype-matched gp120 Env proteins two weeks post-last vaccination (response rates >90 %), while no responses were detected to a heterologous subtype-matched V1V2 antigen. No significant differences were seen between high and low dose groups. Participants in both experimental arms demonstrated nAb response rates of 76.5 % to a tier 1 virus (MW9635.26), but no responses to tier 2 isolates. Env-specific CD4 + T-cell responses were elicited in 36.4 % of vaccine recipients, without significant differences between groups; no participants demonstrated CD8 + T-cell responses.

CONCLUSIONS

Three doses of novel subtype C gp145 Env protein with alum were safe and well-tolerated. Participants demonstrated bAb, Env-specific CD4 + T-cell, and tier 1 nAb responses, but the regimen failed to induce tier 2 or heterologous nAb responses.

CLINICAL TRIALS REGISTRATION

NCT03382418.

Towards Novel HIV-1 Serodiagnostic Tests without Vaccine-Induced Seroreactivity

Vaccine-induced seroreactivity/positivity (VISR/P) poses a significant and common challenge to HIV vaccine implementation, as up to 95% of vaccine recipients may be misclassified as having HIV infection by current HIV screening and confirmatory serological assays. We investigated whether internal HIV proteins could be used to overcome VISR and discovered a set of 4 antigens (gp41 endodomain, p31 integrase, p17 matrix protein, and Nef) that are recognized by antibodies produced in individuals with HIV infection but not in vaccinated individuals. When evaluated in a multiplex double-antigen bridging ELISA, this antigen combination had specificities of 98.1% prevaccination and 97.1% postvaccination, demonstrating the assay is minimally impacted by vaccine-induced antibodies. The sensitivity was 98.5%, further increasing to 99.7% when p24 antigen testing was included. Results were similar across HIV-1 clades. Although more technical advancements will be desired, this research provides the groundwork for the development of new fourth-generation HIV tests unaffected by VISR. IMPORTANCE While the detection of HIV infection is accomplished by several methods, the most common are serological tests that detect host antibodies produced in response to viral infection. However, the use of current serological tests may present a significant challenge to the adoption of an HIV vaccine in the future because the antibodies to HIV antigens detected in currently available tests also tend to be included as antigens in the HIV vaccines in development. The use of these serological tests may thus result in the misclassification of vaccinated HIV-negative individuals, which can have potential for significant harms for individuals and could prevent the widespread adoption and implementation of HIV vaccines. Our study aimed to identify and evaluate target antigens for inclusion in new serological tests that can be used to identify HIV infections without interference from vaccine-induced antibodies but also fit within existing platforms for HIV diagnostics.

Cross-protocol assessment of induction and durability of VISP/R in HIV preventive vaccine trial participants

Candidate HIV vaccines are designed to induce antibodies to various components of the HIV virus. An unintended result of these antibodies is that they may also be detected by commercial HIV diagnostic kits designed to detect an immune response to HIV acquisition. This phenomenon is known as Vaccine-Induced Seropositivity/Reactivity (VISP/R). In order to identify the vaccine characteristics associated with VISP/R, we collated the VISP/R results from 8,155 participants from 75 phase 1/2 studies and estimated the odds of VISP/R by multivariable logistic regression and 10-year estimated probability of persistence in relation to vaccine platform, HIV gag and envelope (env) gene inserts, and protein boost. Recipients of viral vectors, protein boosts, and combinations of DNA and viral-vectored vaccines had higher odds of VISP/R compared to those who received DNA-only vaccines (odds ratio, OR = 10.7, 9.1, 6.8, respectively, p<0.001). Recipients of gp140+ env gene insert (OR = 7.079, p<0.001) or gp120 env (OR = 1.508, p<0.001) had higher odds of VISP/R compared to those participants who received no env. Recipients of gp140 protein had higher odds of VISP/R than those that did not receive protein (OR = 25.155, p<0.001), and recipients of gp120 protein, had lower odds of VISP/R than those that did not receive protein (OR = 0.192, p<0.001). VISP/R persisted at 10 years in more recipients of env gene insert or protein compared to those who did not (64% vs 2%). The inclusion of gag gene in a vaccine regimen had modest effects on these odds and was confounded by other covariates. Participants receiving gp140+ gene insert or protein were most often reactive across all serologic HIV tests. Conclusions from this association analysis will provide insight into the possible impact of vaccine design on the HIV diagnostic landscape and vaccinated populations.

Exploring a community's understanding of HIV vaccine‑induced seropositivity in a South African research setting

BACKGROUND

The high HIV prevalence and incidence in South Africa makes it suitable for recruitment of participants for large-scale HIV preventive vaccine trials. However, fear of vaccine-induced seropositivity (VISP) may be a barrier for community acceptability of the trial, for volunteers to participate in HIV preventive vaccine trials and for uptake of an efficacious vaccine. Prior to 2015, when the first phase 1 safety HIV vaccine trial was undertaken at Setshaba Research Centre, Soshanguve, the local community stakeholders and healthcare workers were naive about HIV vaccine research and HIV preventive vaccines.

OBJECTIVE

To explore knowledge and perceptions regarding VISP among community stakeholders and healthcare workers in peri-urbanb Soshanguve, Tshwane.

METHODS

Using a quantitative-qualitative mixed-methods study design, surveys (n=50) and in-depth interviews (n=18) were conducted during July - August 2015. Participants included community stakeholders, community advisory board members and healthcare workers, who were >18 years old and had attended community educational workshops during September 2014 - May 2015. Audio recordings of interviews were transcribed verbatim and coded using content thematic analysis. Data were further analysed by sex, age and educational level.

RESULTS

Of a maximum score of 2 on knowledge on VISP, the 50 survey participants (mean age 33.78 years; 45 females) obtained an average of 0.88 (44%). Of 17 in-depth interviewees (one interview could not be transcribed; mean age 30.9 years; 12 females), 8 (47%) displayed some knowledge about VISP, of whom only 5 defined VISP correctly. Women were more knowledgeable about VISP than men; 5 of 12 women (42%) came close to defining VISP correctly, while none of the 5 men did so. The main fear of trial participation expressed by most participants (n=6) was testing HIV-positive as a result of the vaccine. While some participants believed that the community's perceptions of VISP would negatively affect HIV vaccine trial support and recruitment efforts, others noted that if trial participants understand the concept of VISP and are part of support groups, then they would have the information to combat negative attitudes within their community.

CONCLUSION

Most participants had an inaccurate and incomplete understanding of VISP. Many feared testing HIV-positive at clinics; therefore, education on improving a basic understanding of how vaccines work and why VISP occurs is essential. In addition, assessing participant understanding of HIV testing, transmission and VISP is critical for recruitment of participants into HIV vaccine trials and may improve acceptability of an HIV preventive vaccine.

Ebola-Detect: A differential serodiagnostic assay for Ebola virus infections and surveillance in the presence of vaccine-induced antibodies

Background

Ebola virus (EBOV) vaccines containing glycoprotein (GP) provide protection against severe Ebola virus disease (EVD). EBO vaccinations elicit antibodies that are detectable in Ebola serodiagnostic tests, as EBOV GP is a major target antigen. This vaccine-induced seropositivity presents issues with early detection of natural EBOV infections, following vaccination and during surveillance, leading to ‘uninfected’ vaccine trial participants being falsely diagnosed as ‘EBOV infected’ potentially resulting in long-term social and economic distress. Since mass vaccinations are being employed to curtail the recurrent EBOV epidemics in multiple African countries, it is, therefore, essential to differentiate vaccine-induced from natural infection–induced antibodies by a differential serodiagnosis assay for accurate detection of Ebola virus infections.

Methods

To develop a serodiagnostic test that can differentiate between individuals with EBOV infection-induced antibodies and individuals with EBOV vaccine-induced antibodies, we analysed peptides of EBOV viral protein 40 (VP40), viral protein 35 (VP35) and nucleocapsid protein (NP) using an ELISA with a panel of 181 human sera collected from healthy controls, EBO vaccinees, and EBOV-infected survivors. Receiver Operating Characteristic (ROC) curve analysis was used to calculate sensitivity and specificity of the assay. A simple peptide-based serodiagnostic assay was used to evaluate detection of breakthrough EBOV infections in vaccinated non-human primates (NHP) in EBOV challenge studies.

Findings

We identified conserved peptide sequences in EBOV VP40, VP35 and NP, produced soon after EBOV infection that are not part of the current EBO vaccine target antigens. The new ELISA-based differential serodetection assay termed ‘EBOV-Detect’ demonstrated >94% specificity and 96% sensitivity for diagnosis of EBOV infection. Importantly, the uninfected vaccine-trial participants scored negative in ‘EBOV-Detect’ assay. The results from the NHPs EBOV challenge study established that post-EBO vaccination serum scored negative in ‘EBOV-Detect’ and all NHPs with Ebola breakthrough infections, following EBOV challenge, were serodiagnosed positively with EBOV-Detect.

Interpretation

The new ‘EBOV-Detect’ is a simple and sensitive serodiagnostic assay that can specifically differentiate between natural Ebola virus infected and those with vaccine-induced immunity. This could potentially be implemented as a robust diagnostic tool for epidemiology and surveillance of EBOV infections during and after outbreaks, especially in countries with mass Ebola vaccinations.

Funding

The antibody characterization work described in this manuscript was supported by FDA Office of Counterterrorism and Emerging Threats (OCET) - Medical Countermeasures initiative (MCMi) grant- OCET 2019-1018 and Defense Threat Reduction Agency (HDTRA1930447) funds to S.K.

Vaccine-Induced Seroreactivity Impacts the Accuracy of HIV Testing Algorithms in Sub-Saharan Africa: An Exploratory Study

The detection of vaccine-induced HIV antibody responses by rapid diagnostic tests (RDTs) may confound the interpretation of HIV testing results. We assessed the impact of vaccine-induced seroreactivity (VISR) on the diagnosis of HIV in sub-Saharan Africa. Samples collected from healthy participants of HIVIS and TaMoVac HIV vaccine trials after the final vaccination were analyzed for VISR using HIV testing algorithms used in Mozambique and Tanzania that employ two sequential RDTs. The samples were also tested for VISR using Enzygnost HIV Integral 4 ELISA and HIV western blot assays. Antibody titers to subtype C gp140 were determined using an in-house enzyme-linked immunosorbent assay (ELISA). The frequency of VISR was 93.4% (128/137) by Enzygnost HIV Integral 4 ELISA, and 66.4% (91/137) by western blot assay (WHO interpretation). The proportion of vaccine recipients that would have been misdiagnosed as HIV-positive in Mozambique was half of that in Tanzania: 26.3% (36/137) and 54.0% (74/137), respectively, p < 0.0001. In conclusion, the HIV RDTs and algorithms assessed here will potentially misclassify a large proportion of the HIV vaccine recipients if no other test is used. Increased efforts are needed to develop differential serological or molecular tools for use at the point of care.

"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.

Ethical considerations for HIV remission clinical research involving participants diagnosed during acute HIV infection

HIV remission clinical researchers are increasingly seeking study participants who are diagnosed and treated during acute HIV infection—the brief period between infection and the point when the body creates detectable HIV antibodies. This earliest stage of infection is often marked by flu-like illness and may be an especially tumultuous period of confusion, guilt, anger, and uncertainty. Such experiences may present added ethical challenges for HIV research recruitment, participation, and retention. The purpose of this paper is to identify potential ethical challenges associated with involving acutely diagnosed people living with HIV in remission research and considerations for how to mitigate them. We identify three domains of potential ethical concern for clinicians, researchers, and ethics committee members to consider: 1) Recruitment and informed consent; (2) Transmission risks and partner protection; and (3) Ancillary and continuing care. We discuss each of these domains with the aim of inspiring further work to advance the ethical conduct of HIV remission research. For example, experiences of confusion and uncertainty regarding illness and diagnosis during acute HIV infection may complicate informed consent procedures in studies that seek to recruit directly after diagnosis. To address this, it may be appropriate to use staged re-consent procedures or comprehension assessment. Responsible conduct of research requires a broad understanding of acute HIV infection that encompasses its biomedical, psychological, social, and behavioral dimensions. We argue that the lived experience of acute HIV infection may introduce ethical concerns that researchers and reviewers should address during study design and ethical approval.

Shifts in UNAIDS ethics guidance and implications for ethics review of preventive HIV vaccine trials

INTRODUCTION

A major change in the ethics framework for preventive HIV vaccine trials worldwide is the release of the UNAIDS 2021 ethical considerations in HIV prevention trials. This new guidance comes at an exciting time when there are multiple HIV vaccine efficacy trials in the field. Research Ethics Committees (RECs) or Institutional Review Boards are a most likely audience for these guidelines. Our objective is to highlight shifts in ethics recommendations from the earlier 2012 UNAIDS guidance.

DISCUSSION

We review recommendations related to four key issues, namely standard of prevention, post-trial access to safe and effective vaccines, enrolment of adolescents and enrolment of pregnant women. We outline implications and make recommendations for the ethics review process, including suggested lines of inquiry by RECs and responses by applicants.

CONCLUSIONS

There have been several shifts in the UNAIDS ethics guidance with implications for HIV vaccine researchers submitting applications for initial ethics review or re-certification, and for RECs conducting such reviews. This review may assist RECs in a more efficient and consistent application of ethics recommendations. However, additional tools and training may further help stakeholders comply with new UNAIDS ethics recommendations during protocol development and ethics review.

An HIV Diagnostic Testing Algorithm Using the cobas HIV-1/HIV-2 Qualitative Assay for HIV Type Differentiation and Confirmation

Human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) diagnostic testing algorithms recommended by the Centers for Disease Control involve up to three tests and rely mostly on detection of viral antigen and host antibody responses. HIV-1 p24 antigen/HIV-1/HIV-2 antibody-reactive specimens are confirmed with an immunochromatographic HIV-1/HIV-2 antibody differentiation assay, and negative or indeterminate results from the differentiation assay are resolved by an HIV-1-specific nucleic acid amplification test (NAT). The performance of a proposed alternative algorithm using the cobas HIV-1/HIV-2 qualitative NAT as the differentiation assay was evaluated in subjects known to be infected with HIV-1 (n = 876) or HIV-2 (n = 139), at low (n = 6,017) or high (n = 1,020) risk of HIV-1 infection, or at high-risk for HIV-2 infection (n = 498) (study A). The performance of the cobas HIV-1/HIV-2 qualitative test was also evaluated by comparison to an HIV-1 or HIV-2 alternative NAT (study B). The HIV-1 and HIV-2 overall percent agreements (OPA) in study A ranged from 95% to 100% in all groups. The positive percent agreements (PPA) for HIV-1 and HIV-2 were 100% (876/876) and 99.4% (167/168), respectively, for known positive groups. The negative percent agreement in the HIV low-risk group was 100% for both HIV-1 and HIV-2. In study B, the HIV-1 and HIV-2 OPA ranged from 99% to 100% in all groups evaluated (n = 183 to 1,030), and the PPA for HIV-1 and HIV-2 were 100% and 99.5%, respectively, for known positive groups. The cobas HIV-1/HIV-2 qualitative assay can discriminate between HIV-1 and HIV-2 based on HIV RNA and can be included in an alternative diagnostic algorithm for HIV.

Poststudy Point-of-Care Oral Fluid Testing in Human Immunodeficiency Virus-1 Vaccinees

Background

Experimental human immunodeficiency virus (HIV)-1 vaccines frequently elicit antibodies against HIV-1 that may react with commonly used HIV diagnostic tests, a phenomenon known as vaccine-induced seropositivity/seroreactivity (VISP/VISR). We sought to determine, under clinic conditions, whether a patient-controlled HIV test, OraQuick ADVANCE Rapid HIV-1/2 Antibody Test, detected HIV-1 vaccine-induced antibodies.

Methods

Plasma assessment of HIV-1 cross-reactivity was examined in end-of-study samples from 57 healthy, HIV-uninfected participants who received a candidate vaccine that has entered Phase 2B and 3 testing. We also screened 120 healthy, HIV-uninfected, unblinded HIV-1 vaccine participants with VISP/VISR for an assessment using saliva. These participants came from 21 different parent vaccine protocols representing 17 different vaccine regimens, all of which contained an HIV-1 envelope immunogen. OraQuick ADVANCE was compared with results from concurrent blood samples using a series of commercial HIV screening immunoassays.

Results

Fifty-seven unique participant plasma samples were assayed in vitro, and only 1 (1.8%) was reactive by OraQuick ADVANCE. None of the 120 clinic participants (0%; 95% confidence interval, 0% to 3.7%) tested positive by OraQuick ADVANCE, and all were confirmed to be uninfected by HIV-1 viral ribonucleic acid testing. One hundred eighteen of the 120 (98.3%) participants had a reactive HIV test for VISP/VISR: 77 (64%) had at least 1 reactive fourth-generation HIV-1 diagnostic test (P < .0001 vs no reactive OraQuick ADVANCE results), and 41 (34%) only had a reactive test by the less specific third-generation Abbott Prism assay.

Conclusions

These data suggest that this widely available patient-controlled test has limited reactivity to HIV-1 antibodies elicited by these candidate HIV-1 vaccines.

Sexual Behaviours and Practices before and after Phase I/II HIV Vaccine Trial: A Qualitative Study among Volunteers in Dar es Salaam Tanzania

There is limited information about sexual behavior among volunteers who participated in phase I/II human immunodeficiency virus (HIV) vaccine trial. This article describes the sexual behavior, practices before, and after participation in phase I/II HIV vaccine trial in Dar es Salaam, Tanzania. We conducted a qualitative descriptive study involving volunteers who participated in the phase I/II vaccine trial between 2007 and 2010. Purposeful sampling was used to recruit potential informants. Twenty-four in-depth interviews were conducted. The audio-recorded interviews were transcribed verbatim and analyzed using a thematic content analysis approach. The findings revealed that before participation in the HIV vaccine trial, informants were engaging in unprotected multiple sexual relationships. After the completion of the HIV vaccine trial, informants reported strengthened marital relationships, increased understanding of safer sexual practices, and HIV testing. However, the informants reported challenges regarding vaccine-induced seropositivity that adversely affected their sexual and marital relationships. Some informants re-engaged in risky sexual practices because they perceived the experimental vaccine was protective. The informants suggested having continued interventions within the community to enhance safer sexual practices. Participation in phase I/II HIV vaccine trials may positively and negatively influence changes in volunteers' sexual behaviors and practices. The trial interventions appear to improve compliance with safer sexual practices. However, the reported vaccine-induced seropositivity and the perception that experimental vaccines are protective need further appropriate interventions.

Social Impacts Among Participants in HIV Vaccine Trial Network (HVTN) Preventive HIV Vaccine Trials

BACKGROUND

Given the persistent stigma and discrimination against HIV worldwide, preventive HIV vaccine trials face unique challenges. Negative social impacts (NSIs)-problems that HIV vaccine trial participants face in many different spheres of their lives related to trial participation-have received a great deal of attention. Beneficial social impacts (BSIs)-perceived benefits experienced by a participant and resulting from their trial participation-are a critical component of participants' experiences, yet they have received little attention.

SETTING

All HIV Vaccine Trials Network trial participants for whom social impact data were available-8347 participants in 13 countries who enrolled in 48 phase 1, 2a, and 2b trials.

METHODS

A cross-protocol analysis to assess self-reported BSIs and NSIs related to participating in a preventive HIV vaccine trial. Data were obtained from 48 completed HIV Vaccine Trials Network vaccine trials from December 2000 to September 2017.

RESULTS

Overall, 6572 participants (81%) reported at least one BSI, and 686 participants (8%) reported 819 NSI events. Altruism/feeling good helping others was the BSI most often endorsed by study participants (43%), followed by receiving risk-reduction counseling (30%). Most NSI events (81%) were reported by US/Swiss participants, and most (79%) trial-related NSIs were negative reactions from friends, family, and partners. Of the NSIs reported, 7% were considered to have a major impact on the participant's quality of life.

CONCLUSION

Our results underscore the relatively common experiences of BSIs among preventive HIV vaccine trial participants and mirror the results of other studies that find infrequent reports of NSIs.

HIV serology false positivity among expatriates from Africa: a screening dilemma

HIV prevalence in Oman is low (<5 %); however, 45 % of the population are expatriates, including a portion originating from countries with high HIV prevalence (>5 %). HIV screening is performed at regional public health laboratories as part of a medical fitness programme for residency applicants. We conducted a retrospective evaluation of indeterminate serology results from 11 females of African origin, aged 21–43 years. Serology testing for HIV was conducted according to the national Oman algorithm: fourth-generation immunoassays (Bio-Rad GS HIV Combo Ag/Ab EIA, Siemens Enzygnost HIV Integral 4, Abbott ARCHITECT HIV Ag/Ab Combo, Roche Elecsys HIV Combi PT, bioMérieux VIDAS HIV DUO QUICK), confirmatory assays (Geenius HIV 1/2 Confirmatory, INNO-LIA HIV I/II Score) and PCR testing. Confirmatory testing to resolve indeterminate results was conducted with available samples for five patients using a combination of immunoassays, confirmatory assays, PCR/PERT and pro-viral DNA levels, at three external laboratories; Roche Diagnostics (Germany), Swiss National Laboratory (Switzerland) and Barts Health NHS Trust (UK). Nineteen serum, 15 plasma and two whole-blood samples were analysed. Nine of ten patients analysed on Bio-Rad and Siemens immunoassays were highly reactive; seven were highly reactive on the Abbott assay. Eight of nine patients tested with the Roche assay were negative. Three of four patients tested on the bioMérieux assay were negative. Five patients underwent confirmatory testing at external laboratories; all were negative by HIV-RNA or pro-viral DNA testing. In conclusion, HIV-RNA and pro-viral DNA testing is recommended for HIV screening of individuals from high-prevalence regions coming to low-prevalence regions.

Prophylactic HIV vaccine: vaccine regimens in clinical trials and potential challenges

Introduction: Ending the HIV epidemic will likely require an efficacious preventative HIV vaccine. As vaccine development progresses, new challenges emerge in the context of an evolving prevention landscape.Areas covered: The progress in HIV vaccine development including trial regimens, results, and impact of pre-exposure prophylaxis (PrEP) including trial design.Expert opinion: Building upon the modest RV144 efficacy results, a follow-up study was launched in South Africa using modified vaccine constructs, ALVAC-HIV vector and gp120 protein boosts (Clade C strains). An adjuvant, MF59, was used to improve durability. Another Phase 2b regimen using an Adenovirus-26 vector with multivalent mosaic antigen inserts and a Clade C gp140 boost advanced into efficacy testing. Current vaccine efficacy studies enroll participants at risk for HIV, offer robust prevention packages, and notably do not restrict PrEP usage. With increasingly efficacious prevention options, future clinical trial designs become more complex. While formally requiring PrEP in HIV vaccine trials (e.g. PrEP ± Vaccine) may maximize protection, it raises both ethical and incremental efficacy over PrEP. Increasing vaccine complexity may lead to persistent vaccine-induced seropositivity, which presents different challenges. Discussion with the community and broader stakeholder engagement will help create solutions to these challenges.

HIV immunoprophylaxis: preparing the pathway from proof of concept to policy decision and use

Various long-awaited efficacy studies of vaccines and broadly neutralising antibodies for prevention of HIV are now well underway in highly endemic settings. One broadly neutralising monoclonal antibody is being assessed for proof of concept, and combinations are in the pipeline. Two multicomponent prime-and-boost vaccine regimens are being evaluated, one of which is designed for global coverage. These multicomponent vaccines present a new level of complexity that will challenge health delivery systems. We recommend that while awaiting the results, which will appear in 2020-22, the target product profiles and full public value proposition for both categories of products should be defined, and the regulatory, policy, and implementation pathways should be prepared. Economic and health benefits, cost of goods, administrative complexity, and user perspectives will be key considerations for the roll-out of effective products. Investments in manufacturing capacity and public-sector delivery systems will be needed to prepare for product introduction and scale-up. We propose a prioritisation of activities on the basis of a broad stakeholder consultation organised by WHO and UNAIDS.

Long-term safety and vaccine-induced seropositivity in healthy volunteers from HIV vaccine trials

BACKGROUND

The ANRS COV1-COHVAC cohort was a long-term safety cohort of healthy volunteers who received preventive HIV-vaccine candidates in 17 phase I/II clinical trials.

METHODS

Data collected from the first vaccine candidate administration and annually after inclusion in the cohort included grade 3/4 adverse events and all grade adverse events suggestive of neurological, ophthalmological and immune disorders, self-administered questionnaires on behaviors and HIV ELISA results. Age-and-sex-standardized mortality ratios (SMRs) were calculated with respect to the French population. The cohort was early terminated in 2016 due to the absence of safety signal.

RESULTS

Of 496 volunteers, 488 were included: 355 in the 7-year prospective follow-up and 133 in the retrospective data collection only. The total follow-up after the first vaccination was 4934 person-years (median: 10 years) and 270 (76%) volunteers completed their follow-up. No relevant adverse event possibly related to the vaccine was reported. Breast cancer incidence and woman mortality did not differ from those of the French general population (standardized incidence ratio = 1.47, P = 0.45 and SMR = 0.65, P = 0.28, respectively) while man mortality was significantly lower (SMR = 0.26, P = 0.0003). At the last visit, 21/29 (72%) volunteers who received the recombinant HIV gp160 protein still showed vaccine-induced seropositivity after a median follow-up of 23 years. Only a few volunteers reported risky sexual practices (men: 20/192, women: 2/162).

CONCLUSION

Volunteers showed a sustained high commitment. No long-term safety alert was identified during the postvaccine follow-up. Participating in vaccine trials did not increase risky behaviors for HIV infection. Vaccine-induced seropositivity may persist for more than 23 years after receiving rgp160.

Social and Behavioral Consequences of Participation in HIV Preventive Vaccine Trials in the ANRS COHVAC Cohort

From 1992 to 2007, the ANRS (France Recherche Nord & Sud Sida-HIV Hépatites) set up a network of healthy volunteers at low risk of HIV infection and participating in preventive HIV vaccine phase I and II trials. The objectives of the ANRS COHVAC volunteer cohort include the social consequences of trial participation and their sexual behavior over time. For 488 volunteers who received a vaccine candidate, 462 selection files were collected, and from 2008 to 2016, 355 volunteers participated in the prospective cohort, including self-administered and face-to-face questionnaires administered annually. The volunteer population is relatively old, with social characteristics and engagement in society rather high. Most volunteers and people around them well accepted the trials, and participation in vaccine trials was not followed by increased risk-taking regarding HIV infection years later.

Being "False Positive": An "Inconvenience"? Debates and Questions Regarding the Notion of Vaccine-Induced Seropositivity (VISP) in the Recruitment of Healthy Volunteers for a Preventive Anti-HIV Vaccine Trial

This article considers a stage in the clinical trial process seldom documented in social sciences: recruitment of healthy volunteers for an HIV preventive vaccine trial through a media campaign. It analyzes one of the consequences of participating in such a clinical trial: the development of vaccine-induced seropositivity (VISP) and how this biomedical notion is mobilized both in recruitment procedures' normative discourses and from the volunteers' points of view, and its consequences on their decision to participate. The interpretations of VISP by volunteers depend on several factors: socialization, itinerary into the recruitment procedure, sexuality, etc., and generates diverse feelings such as indifference, doubt, or even fear. Fear of VISP represents the principal refusal reason for those who interrupted their participating step, just before inclusion stage. Addressing VISP phenomenon is important because it represents a major challenge for the information and the communication procedures for the next anti-HIV prophylactic trials recruitment campaigns.

Challenges to the performance of current HIV diagnostic assays and the need for centralized specimen archives: a review of the Consortium for the Evaluation and Performance of HIV Incidence Assays (CEPHIA) repository

Background: New challenges for diagnosis of HIV infection abound, including the impact on key viral and immunological markers of HIV vaccine studies, pre-exposure prophylaxis usage and breakthrough infections, and very early initiation of anti-retroviral treatment. These challenges impact the performance of current diagnostic assays, and require suitable specimens for development and evaluation. In this article we review and describe an archive developed by the Consortium for the Evaluation and Performance of HIV Incidence Assays (CEPHIA), in order to identify the critical features required to create a centralized specimen archive to support these current and future developments. Review and Findings: We review and describe the CEPHIA repository, a large, consolidated repository comprised of over 31,000 highly-selected plasma samples and other body fluid specimen types, with over 50 purposely designed specimen panels distributed to 19 groups since 2012. The CEPHIA repository provided financial return on investment, supported the standardization of HIV incidence assays, and informed guidance and standards set by the World Health Organization and UNAIDS. Unified data from extensively characterized specimens has allowed this resource to support biomarker discovery, assay optimization, and development of new strategies for estimating duration of HIV infection. Critical features of a high-value repository include 1) extensively-characterized samples, 2) high-quality clinical background data, 3) multiple collaborations facilitating ongoing sample replenishment, and 4) sustained history of high-level specimen utilization. Conclusion: With strong governance and leadership, a large consolidated archive of samples from multiple studies provides investigators and assay developers with easy access to diverse samples designed to address challenges associated with HIV diagnosis, helping to enable improvements to HIV diagnostic assays and ultimately elimination of HIV. Its creation and ongoing utilization should compel funders, institutions and researchers to address and improve upon current approaches to sharing specimens.

"Why Don't You Go Into Suburbs? Why Are You Targeting Us?": Trust and Mistrust in HIV Vaccine Trials in South Africa

Trust is a key element of high-quality stakeholder relations, which are themselves essential for the success of HIV vaccine trials. Where trust is absent, community stakeholders might not volunteer to become involved in key trial activities, and potential participants might not volunteer for enrollment. We explored site staff and Community Advisory Board (CAB) members’ experiences of trust/mistrust among community members and potential participants. We analyzed 10 focus group discussions with site staff and CAB members at two active South African HIV vaccine trial sites. We report on key characteristics perceived to contribute to the trustworthiness of communicators, as well as factors associated with mistrust. Attributes associated with trustworthy communicators included shared racial identity, competence, and independence (not being “captured”). Key foci for mistrust included explanations about site selection, stored samples, vaccination, and Vaccine Induced Sero-Positivity (VISP). Our findings suggest that community members’ trust is not necessarily global, in which trials are trusted or not; rather, it appears fairly nuanced and is impacted by various perceived attributes of communicators and the information they provide. We make recommendations for clinical trial site stakeholders invested in building trust and for future research into trust at these sites.

Impact of Early Antiretroviral Therapy on Detection of Cell-Associated HIV-1 Nucleic Acid in Blood by the Roche Cobas TaqMan Test

The Roche Cobas AmpliPrep/Cobas TaqMan HIV-1 test, v2.0 (the CAP/CTM assay), was used to quantify cell-associated HIV-1 (CAH) nucleic acid in peripheral blood mononuclear cells (PBMC) from well-characterized clinical specimens from HIV-1-infected individuals on antiretroviral therapy (ART). Chronically infected individuals on ART with no detectable plasma HIV-1 RNA demonstrated average CAH burdens of 3.2 HIV-1 log10 copies/million cells. Assay sensitivity and specificity were 98.9% and 100%, respectively, with the positive and negative predictive values being 100% and 98.6%, respectively. The CAH burden was also measured at weeks 0, 1, 2, 8, and 60 in 37 participants (RV254/SEARCH010, Bangkok, Thailand) stratified by Fiebig stage (Fiebig stage I [FI] to FVI) at ART initiation. Prior to ART initiation, the average CAH burden was 1.4, 4.1, and 3.6 log10 copies/million PBMCs for individuals who initiated ART at FI, FII, and FIII to FVI, respectively. Initiation of ART resulted in a rapid decline of CAH in all individuals, with the greatest decrease being observed in individuals who initiated ART at FI to FIII. By week 60, 100% (FI), 71.8% (FII/FIII), and 20.5% (FIV to FVI) of samples from individuals initiating treatment were at or near the limit of quantitation. Residual CAH was detectable at 60 weeks in most individuals who initiated ART at later stages (FIV to FVI) and averaged 1.9 ± 0.7 log10 copies/million PBMCs. The modified Roche CAP/CTM assay provides a convenient, standardized approach to measure residual HIV in blood and may be useful for monitoring patients under therapy or those participating in HIV remission studies.

Targeting and vaccine durability are key for population-level impact and cost-effectiveness of a pox-protein HIV vaccine regimen in South Africa

BACKGROUND

RV144 is to date the only HIV vaccine trial to demonstrate efficacy, albeit rapidly waning over time. The HVTN 702 trial is currently evaluating in South Africa a similar vaccine formulation to that of RV144 for subtype C HIV with additional boosters (pox-protein regimen). Using a detailed stochastic individual-based network model of disease transmission calibrated to the HIV epidemic, we investigate population-level impact and maximum cost of an HIV vaccine to remain cost-effective.

METHODS

Consistent with the original pox-protein regimen, we model a primary series of five vaccinations meeting the goal of 50% cumulative efficacy 24 months after the first dose and include two-yearly boosters that maintain durable efficacy over 10 years. We simulate vaccination programs in South Africa starting in 2027 under various vaccine targeting and HIV treatment and prevention assumptions.

RESULTS

Our analysis shows that this partially effective vaccine could prevent, at catch-up vaccination with 60% coverage, up to 941,000 (15.6%) new infections between 2027 and 2047 assuming current trends of antiretroviral treatment. An impact of up to 697,000 (11.5%) infections prevented could be achieved by targeting age cohorts of highest incidence. Economic evaluation indicates that, if treatment scale-up was achieved, vaccination could be cost-effective at a total cost of less than $385 and $62 per 10-year series (cost-effectiveness thresholds of $5,691 and $750).

CONCLUSIONS

While a partially effective, rapidly waning vaccine could help to prevent HIV infections, it will not eliminate HIV as a public health priority in sub-Saharan Africa. Vaccination is expected to be most effective under targeted delivery to age groups of highest HIV incidence. Awaiting results of trial, the introduction of vaccination should go in parallel with continued innovation in HIV prevention, including studies to determine the costs of delivery and feasibility and further research into products with greater efficacy and durability.

HIV Vaccine Efficacy Trials: RV144 and Beyond

Despite progress in antiretroviral therapy, pre-exposure prophylaxis, microbicides, and other preventive strategies, a vaccine to prevent HIV-1 infection remains desperately needed. Development of an effective vaccine is challenged by several immunologic features of HIV-1 evidenced by the failure of five of the six HIV-1 candidate vaccine efficacy trials to date. This chapter reviews these efficacy trials with a focus on the Phase 3 RV144 trial in Thailand, the only HIV-1 vaccine efficacy trial to show a moderate protective effect of 31% with respect to placebo administration. Although modest, this protection has allowed for the study of potential immunologic correlates of protection to improve development of future HIV-1 pox-protein and other vaccine strategies. Trials in Thailand and South Africa have built upon the RV144 framework to provide additional immunologic insights which enable current and future efficacy testing of related vaccine candidates.

Reported willingness to participate in a hypothetical HIV vaccine trial and its translation to actual participation among healthy adults-Experience from Kenya

Objective

To evaluate initial reported willingness to participate in a hypothetical HIV vaccine clinical trial and actual participation of volunteers in a longitudinal observational study.

Methods

We recruited HIV negative male and female volunteers aged 18–45 years into a longitudinal observational study at KAVI–ICR Kangemi in Kenya, to serve as a pool from which to draw participants into a phase I HIV vaccine clinical trial. A structured questionnaire was used to collect information regarding willingness to join a HIV vaccine clinical trial in the future. Study follow-up visits were every 6 months.

Results

A total of 105 participants were screened and 100 (M46:F54) were enrolled into the observational study. Ninety- four per cent of those enrolled expressed willingness to participate in a future HIV vaccine trial. Altruism and desire to learn the body’s response to the vaccine were the most motivating factors at 40% and 25% respectively. At the onset of a 40-person phase I HIV vaccine trial, 86 observational study participants who had previously expressed willingness to participate were contacted but only 26 (30%) came for information. All 26 consented to participate and after screening for eligibility, 24 were eligible. Of the 24, 15 were enrolled. These numbers were not adequate; hence the vaccine trial employed other recruitment methods to meet the deficit.

Conclusion

Observational “pools” of cohorts may not provide adequate number of participants into vaccine clinical trials even if they report willingness; therefore supplementary recruitment methods such as direct community recruitment, passive approach, and snowballing need to be in place.

Exceptional Risk: Healthy Volunteers' Perceptions of HIV/AIDS Clinical Trials

As with all early-stage testing of investigational drugs, clinical trials targeting HIV/AIDS can pose unknown risks to research subjects. Unlike sick participants seeking a therapeutic benefit, the motivations and barriers for healthy volunteers are more complex and understudied. Drawing on interviews and clinical trial data from 178 healthy volunteers, we examine how they perceive HIV/AIDS studies in the early stages of testing. A subset of healthy volunteers see phase I HIV/AIDS studies as particularly risky for reasons ranging from fear of catching the disease or having long-lasting and uncomfortable side effects to inexplicable fears that they cannot even articulate. Some participants have had past negative experiences in such trials that inform these views, but others cite information from staff and other participants as influential. Healthy volunteers' general fears concerning AIDS also shape their views of participating in phase I HIV/AIDS clinical trials.

p24 revisited: a landscape review of antigen detection for early HIV diagnosis

: Despite major advances in HIV testing, early detection of infection at the point of care (PoC) remains a key challenge. Although rapid antibody PoC and laboratory-based nucleic acid amplification tests dominate the diagnostics market, the viral capsid protein p24 is recognized as an alternative early virological biomarker of infection. However, the detection of ultra-low levels of p24 at the PoC has proven challenging. Here we review the landscape of p24 diagnostics to identify knowledge gaps and barriers and help shape future research agendas. Five hundred and seventy-four research articles to May 2018 that propose or evaluate diagnostic assays for p24 were identified and reviewed. We give a brief history of diagnostic development, and the utility of p24 as a biomarker in different populations such as infants, the newly infected, those on preexposure prophylaxis and self-testers. We review the performance of commercial p24 assays and consider elements such as immune complex disruption, resource-poor settings, prevalence, and assay antibodies. Emerging and ultrasensitive assays are reviewed and show a number of promising approaches but further translation has been limited. We summarize studies on the health economic benefits of using antigen testing. Finally, we speculate on the future uses of high-performance p24 assays, particularly, if available in self-test format.

Barriers and facilitators of HIV vaccine and prevention study participation among Young Black MSM and transwomen in New York City

Background

Black men who have sex with men (MSM), and Transwomen (TW) shoulder disproportionate burden of HIV. However, they are unrepresented in HIV vaccine trials. We investigated the perceptions of that factors associated with HIV vaccine trials participation among Black MSM and TW in New York.

Methods

Self-administered online questionnaires were administered to 18–29 years of NYC residents who identified as Black MSM and TW, assessing demographics, awareness and willingness to participate in HIV vaccine trials, barriers and facilitators associated with willingness, and sexual behaviors. Frequency summation was performed to determine barriers and facilitators, and logistic regression analysis was performed to determine factors association with expressed willingness.

Results

Black MSM and TW who reported engaging in risk behaviors had a 61% lower likelihood of participating in HIV vaccine trials when compared to those who did not report engaging in any risk behavior. Facilitators associated with trial participation were: cash compensation, confidentiality regarding participation, public transportation vouchers, gift cards, and food or grocery vouchers as potential facilitators for trial participation. Conversely, fear of side effects from the vaccine, concerns about testing positive on routine HIV testing due to an HIV vaccine, limited knowledge of research trials, and fear of being judged as HIV-positive were perceived as barriers.

Conclusions

These findings provided insights into the considerations and perceptions of Black MSM and TW towards HIV vaccine trials. However, further studies are needed to delineate the complex mechanisms underlying the decision-making process and establish approaches to increase study participation in this population.

The Influence of Community Members on Participation by Youth in an HIV Vaccine Trial in Tanzania

In sub-Saharan Africa, the burden of HIV is high among young people and it is of the utmost importance that they be recruited into vaccination trials. Since community members influence the willingness of young people to participate in the vaccination trials, ascertaining their opinions is essential to overcoming barriers to such participation. Here, in seven focus group discussions we explored the views of 44 community members identified as someone they felt close by youth in Tanzania. The transcripts of these discussions were examined using content analysis. Our participants expressed that community members would be directly involved in the decisions of young people about whether or not to participate in an HIV vaccine trial. In general, they felt that community members would provide social support for youth during the trial and perceived that youth might have misconceptions concerning the vaccine and trial process. The participants pointed out structural factors such as substance use, poverty, stigma and unemployment that are barriers to participation. In conclusion, involvement of community members could be an integral part of the recruitment and retention of young people in HIV vaccine trials in Tanzania.

Safety and Immunogenicity of a Randomized Phase 1 Prime-Boost Trial With ALVAC-HIV (vCP205) and Oligomeric Glycoprotein 160 From HIV-1 Strains MN and LAI-2 Adjuvanted in Alum or Polyphosphazene

BACKGROUND

Prime-boost regimens comprising ALVAC-HIV (prime) and human immunodeficiency virus type 1 (HIV) Env (boost) induce HIV-specific neutralizing antibody and cell-mediated immune responses, but the impact of boost schedule and adjuvant requires further definition.

METHODS

A phase 1 trial was conducted. In part A (open label), 19 volunteers received oligomeric glycoprotein 160 from HIV strains MN and LAI-2 (ogp160 MN/LAI-2) with dose escalation (25, 50, 100 μg) and either polyphosphazene (pP) or alum adjuvant. In part B, 72 volunteers received either placebo (n=12) or recombinant canarypox virus expressing HIV antigens (ALVAC-HIV [vCP205]) with different doses and schedules of ogp160 MN/LAI-2 in pP or alum (n = 60).

RESULTS

The vaccines were safe and well tolerated, with no vaccine-related serious adverse events. Anti-gp70 V1V2 antibody responses were detected in 17 of 19 part A volunteers (89%) and 10%-100% of part B volunteers. Use of a peripheral blood mononuclear cell-based assay revealed that US-1 primary isolate neutralization was induced in 2 of 19 recipients of ogp160 protein alone (10.5%) and 5 of 49 prime-boost volunteers (10.2%). Among ogp160 recipients, those who received pP were more likely than those who received alum to have serum that neutralized tier 2 viruses (12% vs 0%; P = .015).

CONCLUSIONS

Administration of ogp160 with pP induces primary isolate tier 2 neutralizing antibody responses in a small percentage of volunteers, demonstrating proof of concept and underscoring the importance of further optimization of prime-boost strategies for HIV infection prevention.

CLINICAL TRIALS REGISTRATION

NCT00004579.