The Challenges of Vaccine Trial Participation among Underserved and Hard-to-Reach Communities: An Internal Expert Consultation of the VACCELERATE Consortium

Underserved and hard-to-reach population groups are under-represented in vaccine trials. Thus, we aimed to identify the challenges of vaccine trial participation of these groups in member countries of the VACCELERATE network. Seventeen National Coordinators (NC), each representing their respective country (15 European countries, Israel, and Turkey), completed an online survey. From 15 eligible groups, those that were more frequently declared underserved/hard-to-reach in vaccine research were ethnic minorities (76.5%), persons experiencing homelessness (70.6%), illegal workers and refugees (64.7%, each). When prioritization for education on vaccine trials was considered, ethnic groups, migrants, and immigrants (5/17, 29.4%) were the groups most frequently identified by the NC as top targets. The most prominent barriers in vaccine trial participation affecting all groups were low levels of health literacy, reluctance to participate in trials due to engagement level, and low levels of trust in vaccines/vaccinations. This study highlighted population groups considered underserved/hard-to-reach in countries contained within the European region, and the respective barriers these groups face when participating in clinical studies. Our findings aid with the design of tailored interventions (within-and across-countries of the European region) and with the development of strategies to overcome major barriers in phase 2 and phase 3 vaccine trial participation.

Should HIV Vaccines Be Made Available at No or Subsidized Cost? A Qualitative Inquiry of HIV Vaccine Trial Stakeholders in Tanzania

BACKGROUND

The world has come closer than ever to discovering a viable HIV vaccine. However, it remains less certain whether HIV vaccines should be made available to participants and communities in which trials are run no or subsidized cost. Hence the essence of this inquiry.

METHODOLOGY

This is a case study design using in-depth interviews (IDI) and focus group discussions (FGD) with researchers of HIV vaccine trials, institutional review board (IRB) members, HIV advocates, a policy maker, and members of community advisory board (CAB) in Tanzania. Participants were purposively selected and data thematically analyzed using MAXQDA software.

RESULTS

Hosting a vaccine trial and the financial incapacity of individuals at increased risk of HIV were among the reasons in favor of free access to HIV vaccines. In contrast, the view that vaccines should be provided at a subsidized cost was related to high costs of vaccine development, financial return expectations by investors, and the fear of labeling the free vaccine as less important. Moreover, apart from governments and international organizations, well-off individuals could share the cost burden.

CONCLUSION

Stakeholders engaging in active discussion about sharing the viable vaccine ought to take the aforementioned concerns into account and ensure unhindered access to individuals and host communities in Tanzania and beyond.

An Overview of SARS-CoV-2 Etiopathogenesis and Recent Developments in COVID-19 Vaccines

The Coronavirus disease-2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has significantly impacted the health and socioeconomic status of humans worldwide. Pulmonary infection of SARS-CoV-2 results in exorbitant viral replication and associated onset of inflammatory cytokine storm and disease pathology in various internal organs. However, the etiopathogenesis of SARS-CoV-2 infection is not fully understood. Currently, there are no targeted therapies available to cure COVID-19, and most patients are treated empirically with anti-inflammatory and/or anti-viral drugs, based on the disease symptoms. Although several types of vaccines are currently implemented to control COVID-19 and prevent viral dissemination, the emergence of new variants of SARS-CoV-2 that can evade the vaccine-induced protective immunity poses challenges to current vaccination strategies and highlights the necessity to develop better and improved vaccines. In this review, we summarize the etiopathogenesis of SARS-CoV-2 and elaborately discuss various types of vaccines and vaccination strategies, focusing on those vaccines that are currently in use worldwide to combat COVID-19 or in various stages of clinical development to use in humans.

A qualitative study of stakeholder and researcher perspectives of community engagement practices for HIV vaccine clinical trials in South Africa

Community engagement increases community trust of research and improves trial participation. However, there is limited documented appraisal of community engagement practices. Several HIV vaccine efficacy trials have been conducted in South Africa, the country most affected by HIV, predominantly in collaboration with the HIV Vaccine Trials Network (HVTN). We explored stakeholder and researcher perspectives of the HVTN community engagement practices used in the Gauteng province of South Africa. In 2017, we conducted a qualitative study. Using semi-structured interview guides, we facilitated two group discussions with Community Advisory Board (CAB) members (n = 13), and 14 in-depth interviews with HVTN-affiliated employees (n = 8 in South Africa and n = 6 in the USA). Group discussions and in-depth interviews were audio-recorded, transcribed verbatim, translated into English, and coded using NVIVO 12 Plus software for thematic data analysis. Overall, median age of study participants was 22 (interquartile range 32-54) years, and 74% (n = 20) were female. Three main themes about community engagement emerged: (i) community engagement as an ongoing iterative relationship between researchers and community; (ii) methods of community engagement, encompassing community education by linking with external stakeholders and through awareness campaigns by pamphlet distribution and mass events, working with communities to develop recruitment messages, and working with CAB as a link to communities; and (iii) strategies to improve community engagement, for example, using simple language, linking with religious leaders and traditional healers, and communicating via conventional (newspapers, television, and radio) and social (videos and listicles) media. Our data indicate ways for researchers to improve relationships with community by understanding local needs, strengthening collaborations, and tailoring communication strategies. In this regard, CABs signify critical linkages between researchers and communities. CABs can relay relevant health research needs, advise on the creation of suitable materials, and link researchers more effectively with community leaders and media.

Vaccine clinical trials with dynamic borrowing of historical controls: Two retrospective studies

Traditional vaccine efficacy trials usually use fixed designs with fairly large sample sizes. Recruiting a large number of subjects requires longer time and higher costs. Furthermore, vaccine developers are more than ever facing the need to accelerate vaccine development to fulfill the public's medical needs. A possible approach to accelerate development is to use the method of dynamic borrowing of historical controls in clinical trials. In this paper, we evaluate the feasibility and the performance of this approach in vaccine development by retrospectively analyzing two real vaccine studies: a relatively small immunological trial (typical early phase study) and a large vaccine efficacy trial (typical Phase 3 study) assessing prophylactic human papillomavirus vaccine. Results are promising, particularly for early development immunological studies, where the adaptive design is feasible, and control of type I error is less relevant.

Inclusionary Trials: A Review of Lessons Not Learned

The COVID-19 pandemic revealed weaknesses in the public health infrastructure of the United States, including persistent barriers to engaging marginalized communities toward inclusion in clinical research, including trials. Inclusive participation in clinical trials is crucial for promoting vaccine confidence, public trust, and addressing disparate health outcomes. A long-standing body of literature describes the value of community-based participatory research in increasing marginalized community participation in research. Community-based participatory research emphasizes shared leadership with community members in all phases of the research process, including in the planning and implementation, interpretation, and dissemination. Shared leadership between academic and industry with marginalized communities can assist with inclusive participation in vaccine trials and increase public trust in the development of the vaccines and other therapies used during public emergencies. Nevertheless, epidemiologic and clinical research do not yet have a strong culture of community partnership in the scientific process, which takes time to build and therefore may be difficult to develop and rapidly scale to respond to the pandemic. We outline practices that contribute to a lack of inclusive participation and suggest steps that trialists and other researchers can take to increase marginalized communities' participation in research. Practices include planning for community engagement during the planning and recruitment phases, having regular dialogues with communities about their priorities, supporting them throughout a study, and navigating complex structural determinants of health. Additionally, we discuss how research institutions can support inclusive practices by reexamining their policies to increase participation in clinical trials and instilling institutional trustworthiness.

A community-partnered approach for diversity in COVID-19 vaccine clinical trials

Introduction

Communities of color have faced disproportionate morbidity and mortality from COVID-19, coupled with historical underrepresentation in US clinical trials, creating challenges for equitable participation in developing and testing a safe and effective COVID-19 vaccine.

Methods

To increase diversity, including racial and ethnic representation, in local Los Angeles County NIH-sponsored Phase 3 SARS-CoV-2 vaccine clinical trials, we used deliberative community engagement approaches to form a Community Consultant Panel (CCP) that partnered with trial research teams. Thirteen members were recruited, including expertise from essential workers, community-based and faith-based organizations, or leaders from racial and ethnic minority communities.

Results

Working closely with local investigators for the vaccine studies, the CCP provided critical insight on best practices for community trust building, clinical trial participation, and reliable information dissemination regarding COVID-19 vaccines. Modifying recruitment, outreach, and trial protocols led to majority-minority participants (55%-78%) in each of the three vaccine clinical trials. CCP's input led to cultural tailoring of recruitment materials, changes in recruitment messaging, and supportive services to improve trial accessibility and acceptability (transportation, protocols for cultural competency, and support linkages to care in case of an adverse event). Barriers to clinical trial participation unable to be resolved included childcare, requests for after-hours appointment availability, and mobile locations for trial visits.

Conclusion

Using deliberative community engagement can provide critical and timely insight into the community-centered barriers to COVID-19 vaccine trial participation, including addressing social determinants of health, trust, clinical trial literacy, structural barriers, and identifying trusted messenger and reliable sources of information.

Conditional power in vaccine trials with seasonal variations

Conditional power (CP) is widely used in clinical trial monitoring to quantify the evidence for futility stopping or sample size adaptation during the trial. When planning an interim analysis in vaccine trials for seasonal infectious diseases, CPs calculated under the hypothesized or currently estimated effect sizes may not truly reflect future data due to seasonal variations in disease incidence and/or vaccine efficacy (VE). Relying on these estimates alone could lead to erroneous decisions. Therefore, we carried out simulation studies to investigate the use of seven different choices for the drift parameter in computing CP or predictive power (PP) in end-of-season interim analysis. Our simulations showed that, when used to inform futility stopping, CP under the hypothesized effect and a weighted PP under a normal prior distribution appear to outperform others in terms of the overall type II error rate. All CPs and PPs considered in this study resulted in comparable powers and expected sample sizes when used to inform sample size adaptation. The performance of either CP or PP largely depends on the extent to which the chosen drift parameter or the prior distribution of the drift parameter matches the remainder of the trial. Weighted CP/PP tends to be less sensitive to settings where observed data and emerging data in future seasons differ substantially as they incorporate both current estimate and future variations. Therefore, weighted strategies deserve further exploration and perhaps increased usage in guiding trial operations because they are more robust to inaccuracies in prediction. In summary, for vaccine trials with seasonal variations, a decision on trial operations should be guided by a careful consideration of plausible CPs and PPs calculated under reasonable assumptions leveraging the data, prior hypotheses, and new evidence on clinical relevance.

Nonparametric estimation of the causal effect of a stochastic threshold-based intervention

Identifying a biomarker or treatment-dose threshold that marks a specified level of risk is an important problem, especially in clinical trials. In view of this goal, we consider a covariate-adjusted threshold-based interventional estimand, which happens to equal the binary treatment-specific mean estimand from the causal inference literature obtained by dichotomizing the continuous biomarker or treatment as above or below a threshold. The unadjusted version of this estimand was considered in Donovan et al.. Expanding upon Stitelman et al., we show that this estimand, under conditions, identifies the expected outcome of a stochastic intervention that sets the treatment dose of all participants above the threshold. We propose a novel nonparametric efficient estimator for the covariate-adjusted threshold-response function for the case of informative outcome missingness, which utilizes machine learning and targeted minimum-loss estimation (TMLE). We prove the estimator is efficient and characterize its asymptotic distribution and robustness properties. Construction of simultaneous 95% confidence bands for the threshold-specific estimand across a set of thresholds is discussed. In the Supporting Information, we discuss how to adjust our estimator when the biomarker is missing at random, as occurs in clinical trials with biased sampling designs, using inverse probability weighting. Efficiency and bias reduction of the proposed estimator are assessed in simulations. The methods are employed to estimate neutralizing antibody thresholds for virologically confirmed dengue risk in the CYD14 and CYD15 dengue vaccine trials.

Leveraging Pathogen Sequence and Contact Tracing Data to Enhance Vaccine Trials in Emerging Epidemics

INTRODUCTION

Advance planning of vaccine trials conducted during outbreaks increases our ability to rapidly define the efficacy and potential impact of a vaccine. Vaccine efficacy against infectiousness (VEI) is an important measure for understanding a vaccine's full impact, yet it is currently not identifiable in many trial designs because it requires knowledge of infectors' vaccination status. Recent advances in genomics have improved our ability to reconstruct transmission networks. We aim to assess if augmenting trials with pathogen sequence and contact tracing data can permit them to estimate VEI.

METHODS

We develop a transmission model with a vaccine trial in an outbreak setting, incorporate pathogen sequence data and contact tracing data, and assign probabilities to likely infectors. We then propose and evaluate the performance of an estimator of VEI.

RESULTS

We find that under perfect knowledge of infector-infectee pairs, we are able to accurately estimate VEI. Use of sequence data results in imperfect reconstruction of transmission networks, biasing estimates of VEI towards the null, with approaches using deep sequence data performing better than approaches using consensus sequence data. Inclusion of contact tracing data reduces the bias.

CONCLUSION

Pathogen genomics enhance identifiability of VEI, but imperfect transmission network reconstruction biases estimate toward the null and limits our ability to detect VEI. Given the consistent direction of the bias, estimates obtained from trials using these methods will provide lower bounds on the true VEI. A combination of sequence and epidemiologic data results in the most accurate estimates, underscoring the importance of contact tracing.

RNA-Based COVID-19 Vaccine Candidates with Clinical Phase Trials in Progress

Due to the COVID-19 infection, which was recognized as a global pandemic by the WHO on March 11, 2020, the number of cases and disease-related deaths increases day by day globally. For this reason, antiviral agents used in treatment and vaccines, the most effective weapon in prevention, continue to be the most popular topic of the plan. Several situations are expected to affect the course of the pandemic. The loss of the ability of the virus to mutate and cause disease, the fact that those who become immunized by having the disease in the society reach a critical rate and create social immunity (herd immunity), and the provision of social immunity with effective vaccination can be counted as some of these situations.Candidate vaccines in the clinical phase among RNA-based vaccines: This review aimed to examine COVID-19 vaccine candidates using RNA technology and compile its current data. We used PubMed, Google Scholar, and World Health Organization (WHO) databases. Also, we followed up on the latest news and developments on vaccine companies’ websites.Conclusion: Vaccination trials, which started due to the seriousness and urgency of the situation that we are in, continue exceptionally quickly and effectively. As per the WHO›s data on July 9, 2021, there have been 291 vaccine trials, 107 of which are in the clinical phase, and 18 (16%) of the vaccine candidates in the clinical phase are RNA-based vaccines. Also, the number of RNA-based vaccines with ongoing preclinical trials is 2

Assurance in vaccine efficacy clinical trial design based on immunological responses

The assurance of a future clinical trial is a key quantitative tool for decision-making in drug development. It is derived from prior knowledge (Bayesian approach) about the clinical endpoint of interest, typically from previous clinical trials. In this paper, we examine assurance in the specific context of vaccine development, where early development (Phase 2) is often based on immunological endpoints (e.g., antibody levels), while the confirmatory trial (Phase 3) is based on the clinical endpoint (very large sample sizes and long follow-up). Our proposal is to use the Phase 2 vaccine efficacy predicted by the immunological endpoint (using a model estimated from epidemiological studies) as prior information for the calculation of the assurance.

Factors associated with parents' willingness to enroll their children in trials for COVID-19 vaccination

The coronavirus disease 2019 (COVID-19) pandemic has taken an unprecedented global toll and vaccination is needed to restore healthy living. Timely inclusion of children in vaccination trials is critical. We surveyed caregivers of children seeking care in 17 Emergency Departments (ED) across 6 countries during the peak of the pandemic to identify factors associated with intent to participate in COVID-19 vaccine trials. Questions about child and parent characteristics, COVID-19 expressed concerns and parental attitudes toward participation in a trial were asked.Of 2768 completed surveys, 18.4% parents stated they would enroll their child in a clinical trial for a COVID-19 vaccine and 14.4% would agree to a randomized placebo-controlled study. Factors associated with willingness to participate were parents agreeing to enroll in a COVID-19 vaccine trial themselves (Odds Ratio (OR) 32.9, 95% Confidence Interval (CI) (21.9-51.2)) having an older child (OR 1.0 (1.0-1.01)), having children who received all vaccinations based on their country schedule (OR 2.67 (1.35-5.71)) and parents with high school education or lower (OR 1.79 (1.18-2.74)). Mothers were less likely to enroll their child in a trial (OR 0.68 (0.47-0.97)). Only one fifth of families surveyed will consider enrolling their child in a vaccine trial. Parental interest in participation, history of vaccinating their child, and the child being older all are associated with parents allowing their child to participate in a COVID vaccine trial. This information may help decision-makers and researchers shape their strategies for trial design and participation engagement in upcoming COVID19 vaccination trials.

Emerging trends from COVID-19 research registered in the Clinical Trials Registry - India

Since the beginning of the year, the deadly coronavirus pandemic, better known as coronavirus disease 2019 (COVID-19), brought the entire world to an unprecedented halt. In tandem with the global scenario, researchers in India are actively engaged in the conduct of clinical research to counter the pandemic. This review attempts to provide a comprehensive overview of the COVID-19 research in India including design aspects, through the clinical trials registered in the Clinical Trials Registry - India (CTRI) till June 5, 2020. One hundred and twenty two registered trials on COVID-19 were extracted from the CTRI database. These trials were categorized into modern medicine (n=42), traditional medicine (n=67) and miscellaneous (n=13). Of the 42 modern medicine trials, 28 were on repurposed drugs, used singly (n=24) or in combination (n=4). Of these 28 trials, 23 were to evaluate their therapeutic efficacy in different severities of the disease. There were nine registered trials on cell- and plasma-based therapies, two phytopharmaceutical trials and three vaccine trials. The traditional medicine trials category majorly comprised Ayurveda (n=45), followed by homeopathy (n=14) and others (n=8) from Yoga, Siddha and Unani. Among the traditional medicine category, 31 trials were prophylactic and 36 were therapeutic, mostly conducted on asymptomatic or mild-to-moderate COVID-19 patients. This review would showcase the research being conducted on COVID-19 in the country and highlight the research gaps to steer further studies.

Does a Public Health Crisis Justify More Research with Incarcerated People?

Covid-19 has infected thousands and killed hundreds in prisons, jails, and immigration detention facilities across the United States. Responding to this crisis, leading medical researchers have called for expanding opportunities for people in prison to participate in vaccine trials. These calls, like current regulations, focus on individualized risk assessments around consent, coercion, and harm, while ignoring the unnaturalness of deprivation conditions in U.S. prisons. We need new frameworks of analysis that refocus on structural, rather than individual, risk assessments. Integrating structural perspectives-including skepticism of claims of scarcity, avoidance of representational distortions, and attention to institutional agency-into our existing, overly individualistic frameworks might permit the design of more ethical research projects involving people who are incarcerated. Still, the unnatural deprivations of incarceration might be so great that research subjects might need to be removed from prison entirely in order to ethically participate in research.

Challenge Trials: What Are the Ethical Problems?

If, as is alleged, challenge trials of vaccines against COVID-19 are likely to save thousands of lives and vastly diminish the economic and social harms of the pandemic while subjecting volunteers to risks that are comparable to kidney donation, then it would seem that the only sensible objection to such trials would be to deny that they have low risks or can be expected to have immense benefits. This essay searches for a philosophical rationale for rejecting challenge trials while supposing that they have huge benefits and relatively low risks. Although it finds some force in objections to challenge trials grounded in the obligations of researchers to limit the harms imposed on some individuals for the benefit of others, it argues that there is no compelling objection to challenge trials of vaccines for COVID-19-if they have the benefits and risks that have been claimed.

A Review of Adherence and Predictors of Adherence to the CONSORT Statement in the Reporting of Tuberculosis Vaccine Trials

The statement on Consolidated Standards of Reporting Trials (CONSORT) ensures transparency in the reporting of randomized trials. However, it is unclear if the statement has led to improvement in the quality of reporting of tuberculosis (TB) vaccine trials. We explored the quality of reporting of TB vaccine trials according to the latest version of the CONSORT statement, released in 2010. We searched PubMed and the Cochrane Central Register of Controlled Trials in August 2019. We conducted screening, study selection, and data extraction in duplicate; and resolved differences through discussion. We assessed reporting to be adequate if trials reported at least 75% of the CONSORT 2010 items. We conducted a trend analysis to assess if there was improvement in reporting over time. We also used logistic regression to assess factors associated with adequate reporting. We included 124 trials in the analyses. The mean proportion of adherence was 67.3% (95% confidence interval 64.4% to 70.1%), with only 46 (37%) trials having adequate reporting. There was a significant improvement in the quality of reporting over time (p < 0.0001). Trials published in journals with impact factors between 10 and 20 were more likely to have adequate reporting (odds ratio 9.4; 95% confidence interval 1.30 to 67.8), compared to lower-impact-factor journals. Despite advances over time, the reporting of TB vaccine trials is still inadequate and requires improvement.

Statistical Properties of Stepped Wedge Cluster-Randomized Trials in Infectious Disease Outbreaks

Randomized controlled trials are crucial for the evaluation of interventions such as vaccinations, but the design and analysis of these studies during infectious disease outbreaks is complicated by statistical, ethical, and logistical factors. Attempts to resolve these complexities have led to the proposal of a variety of trial designs, including individual randomization and several types of cluster randomization designs: parallel-arm, ring vaccination, and stepped wedge designs. Because of the strong time trends present in infectious disease incidence, however, methods generally used to analyze stepped wedge trials might not perform well in these settings. Using simulated outbreaks, we evaluated various designs and analysis methods, including recently proposed methods for analyzing stepped wedge trials, to determine the statistical properties of these methods. While new methods for analyzing stepped wedge trials can provide some improvement over previous methods, we find that they still lag behind parallel-arm cluster-randomized trials and individually randomized trials in achieving adequate power to detect intervention effects. We also find that these methods are highly sensitive to the weighting of effect estimates across time periods. Despite the value of new methods, stepped wedge trials still have statistical disadvantages compared with other trial designs in epidemic settings.

No Correlation Between Ethical Judgment in Trolley Dilemmas and Vaccine Scenarios for Nurse Specialist Students

We tested whether responses to trolley problems by nurse specialist students correlated with their responses to hypothetical vaccine problems, as a follow-up to a similar study on ethics committees. No statistically significant correlation was found between the trolley and vaccination scores. These results confirmed and strengthened the finding of a very weak correlation (possibly zero), and the point estimate was even lower than for the ethics committees. Hence, the nurse specialists' responses to the trolley problems cannot be used to indicate any direction for their responses to the vaccine problems, although there is a common core issue of sacrificing some for many. The respondents reported a relatively high willingness to push one man in front of a trolley to save five. They also reported a high willingness to act in trolley dilemmas compared with vaccination dilemmas, although the dimensions of risk-reward ratios and consent heavily favored the latter.

Estimands and inference in cluster-randomized vaccine trials

Cluster-randomized trials are often conducted to assess vaccine effects. Defining estimands of interest before conducting a trial is integral to the alignment between a study's objectives and the data to be collected and analyzed. This paper considers estimands and estimators for overall, indirect, and total vaccine effects in trials, where clusters of individuals are randomized to vaccine or control. The scenario is considered where individuals self-select whether to participate in the trial, and the outcome of interest is measured on all individuals in each cluster. Unlike the overall, indirect, and total effects, the direct effect of vaccination is shown in general not to be estimable without further assumptions, such as no unmeasured confounding. An illustrative example motivated by a cluster-randomized typhoid vaccine trial is provided.

Communities and Clinical Trials: A Case Study from the RTS,S Malaria Vaccine Trials in Eastern Africa

When clinical trials enter human communities, two complex systems merge-creating challenges for the clinical trial team and the local human community. This is of particular relevance for clinical trials in low-resource settings where the resource scarcity can intensify existing inequities. Here we present a case study of a phase III malaria vaccine clinical trial. Through qualitative interviews with researchers and caregivers of pediatric participants we elucidate themes that shape the clinical trial system. These themes can be a useful complementary planning tool to existing research guidelines for clinical trial researchers. Respondents from both groups reported financial and social contextual realities to be major drivers in the system. We found a strong historical path dependency in the community that was closely tied to the relationships with researchers and indicative of the structural inequities. We elaborate on these findings and offer recommendations to improve trial design.

The Case for Why Africa Should Host COVID-19 Candidate Vaccine Trials

In response to provocative comments by 2 European clinicians and scientists, the World Health Organization Director General has declared that Africa will not host COVID-19 vaccine trials. Such a stance risks stigmatizing COVID-19 vaccine trials in Africa and depriving Africa of critical research. To the contrary, there is a critical need for Africa to host COVID-19 vaccine trials on public health, scientific, and ethics grounds.

Primary physicians' attitudes toward their patients receiving a proposal to participate in a vaccine trial

A trustworthy relationship between primary physicians (PPs) and their patients is crucial for vaccine acceptance. Little is known about attitudes of PPs toward participation of their patients in a preventive vaccine trial (PVT) proposed by investigation sites.A cross-sectional study was conducted in Auvergne-Rhône-Alpes region (France) including an anonymous questionnaire for general practitioners (GPs) and other specialists as well as face-to-face interviews. A scenario of a patient, with chronic medical conditions, invited to participate in a PVT and reporting this situation to his/her PP was drawn up. PPs' attitudes were assessed in quantitative approach by a 5-point Likert scale and in qualitative approach by semi-directed individual interviews.Among the 521 respondents to the questionnaire, 429 (82.3%) were GPs and 92 (17.7%) were other specialists. Only 7.5% (39/521) of respondents regularly practice clinical research. Confronted with the scenario, 312 respondents (59.8%) declared they would give their opinion spontaneously. Before giving their opinion, PPs would like more information about the trial (91.4%, n = 476). Whatever their attitude, 488 (93.7%) would be influenced by available safety data. Face-to-face interviews confirmed that PPs lack of knowledge about clinical research, and would like to obtain information from investigators, particularly about safety.PPs seem to be concerned by the decision of their patients to participate or not in a PVT but would like more information about the trial and clinical research before giving their opinion. Getting PPs to be more involved in the enrollment of patients in PVT may improve recruitment.

Methods for comparing durability of immune responses between vaccine regimens in early-phase trials

The ability to produce a long-lasting, or durable, immune response is a crucial characteristic of many highly effective vaccines. A goal of early-phase vaccine trials is often to compare the immune response durability of multiple tested vaccine regimens. One parameter for measuring immune response durability is the area under the mean post-peak log immune response profile. In this paper, we compare immune response durability across vaccine regimens within and between two phase I trials of DNA-primed HIV vaccine regimens, HVTN 094 and HVTN 096. We compare four estimators of this durability parameter and the resulting statistical inferences for comparing vaccine regimens. Two of these estimators use the trapezoid rule as an empirical approximation of the area under the marginal log response curve, and the other two estimators are based on linear and nonlinear models for the marginal mean log response. We conduct a simulation study to compare the four estimators, provide guidance on estimator selection, and use the nonlinear marginal mean model to analyze immunogenicity data from the two HIV vaccine trials.

Trolley Dilemmas Fail to Predict Ethical Judgment in a Hypothetical Vaccination Context

We investigated whether the responses of 68 ethics committee members and staff to trolley dilemmas could predict their responses to research ethics problems concerning vaccine trials. Trolley dilemmas deal with the issue of sacrificing some for the benefit of many, which is also a core issue in the vaccination trial dilemmas. The subjects' responses to trolley dilemmas showed no statistically significant correlation with their responses to our vaccination trial dilemmas. We concluded that, if there is a component of transferable intuition between the contexts, it must be small and dominated by other factors. Furthermore, the willingness to sacrifice some for many was larger in the trolley context, despite a more favorable risk/reward ratio and the voluntary participation of the subjects at risk in the vaccination situations. We conclude that one's general willingness to trade lives in the trolley context may be an artifact that is due to its unrealistic setting.

Therapeutic Vaccine Against HIV, Viral Variability, Cytotoxic T Lymphocyte Epitopes, and Genetics of Patients

The scientific and medical community is seeking to cure HIV. Several pathways have been or are being explored including therapeutic vaccination. Viroimmunological studies on primary infection as well as on elite controllers have demonstrated the importance of the cytotoxic CD8 response and have mainly oriented research on vaccine constructs toward this type of response. The results of these trials are clearly not commensurate with the hope placed in them. Might there be one or more uncontrolled variables? The genetics of patients need to be taken into consideration, especially their human lymphocyte antigen (HLA) alleles. There is a need to find a balance between the conservation of cytotoxic T lymphocyte (CTL) epitopes and presentation by HLA alleles. The pathway is a narrow one between adaptation of the virus to HLA I restriction and the definition of conserved proviral CTL epitopes presentable by HLA I alleles. It is likely that the genetics of patients will need to be considered for HIV-1 vaccine studies and that multidisciplinary collaboration will be essential in this field of infectious diseases.

New ethical considerations in vaccine trials

Known and novel pathogens continue to afflict the world's population, and we deploy existing and new vaccines - the best type of weapon we've got - against them. One consequence is that we are accumulating steadily more experience of both the scientific and the ethical requirements of conducting vaccine trials in people. Good science is itself an ethical requirement, as it is meaningless to apply ethical principles to a scientifically flawed product or plan. Bad science can only be bad ethics. And we have learned that ethical principles are a necessity when we apply the benefits of science to the improving of human health. Recent epidemics have provided opportunities to expand our understanding of this field and of the many components of it that we recognize to be necessary to the ethical assessment of vaccines.

High-throughput monitoring of human tumor-specific T-cell responses with large peptide pools

In immune intervention trials, the comprehensive investigation of immunogenicity or T-cell epitope-mapping is challenging especially when a large set of epitopes needs to be screened and limited sample material is available. To this end, T-cell responses are often monitored using peptide pools. Here, we assessed the magnitude and sensitivity of detection of antigen-specific CD8⁺ and CD4⁺ T cells using a single peptide alone or mixed into large pools. Interestingly the magnitude of ex vivo anti-viral and anti-tumor T-cell responses was identical irrespective of the presence and number of irrelevant peptides, in different functional assays with PBMCs from healthy donors and cancer patients. Moreover, the presence of up to 300 irrelevant peptides did not affect the threshold of responsiveness of antigen-specific CD8⁺ T cells to single cognate peptides. These data demonstrate the relevance of using very large peptide pools for the sensitive and specific immune-monitoring of epitope-specific T cells in natural or immune-modulated context.

Peruvian Female Sex Workers' Ethical Perspectives on Their Participation in an HPV Vaccine Clinical Trial

This study examined female sex workers' evaluation of ethically relevant experiences of participating in an HPV4 vaccine clinical trial conducted in Lima, Peru (the Sunflower Study). The Sunflower Study provided all participants with HPV testing, treatment for those testing positive, and access to the vaccine for all testing negative. Themes that emerged from content analysis of interviews with 16 former participants included the importance of respectful treatment and access to healthcare not otherwise available and concerns about privacy protections, the potential for HIV stigma, and poststudy abandonment.

The HVTN503/Phambili HIV vaccine trial: a comparison of younger and older participants

By comparing younger to older participants enrolled in a HIV vaccine efficacy trial, we aimed to gain insights into the inclusion of adolescents in future trials. This was a sub-analysis of a multisite HIV vaccine randomized clinical trial in South Africa, conducted January-September 2007. Motivations for trial enrolment, social harms, adverse events and loss to follow-up were compared between younger (18-20 years old) and older participants (21-35 years old). Both younger (n = 238) and older participants (n = 563) were equally likely to report enrolling for altruistic reasons. Younger females were less likely than older participants to join for trial reimbursement (p = 0.005), while younger males were more likely to enrol because the vaccine may provide protection from HIV-acquisition (p < 0.001). There were no significant differences in the number of social harms reported. Compared to males over 20 years old, 18-20-year-old females were less likely to experience adverse events (OR = 0.1, CI 0.01-0.80) and no more likely to be lost to follow-up (OR = 0.7, CI 0.39-1.25), while 18-20-year-old males were no more likely to experience adverse events (OR = 1.3, CI 0.58-2.83) or loss to follow-up (OR = 0.8, CI 0.51-1.41). Our data support the inclusion of younger participants who are at risk for HIV in future HIV vaccine efficacy trials.

Effect partitioning under interference in two-stage randomized vaccine trials

In the presence of interference, the exposure of one individual may affect the outcomes of others. We provide new effect partitioning results under interferences that express the overall effect as a sum of (i) the indirect (or spillover) effect and (ii) a contrast between two direct effects.

Taking social relationships seriously: lessons learned from the informed consent practices of a vaccine trial on the Kenyan Coast

Individual informed consent is a key ethical obligation for clinical studies, but empirical studies show that key requirements are often not met. Common recommendations to strengthen consent in low income settings include seeking permission from community members through existing structures before approaching individuals, considering informed consent as a process rather than a single event, and assessing participant understanding using questionnaires. In this paper, we report on a qualitative study exploring community understanding and perceptions of a malaria vaccine trial (MVT) conducted in a rural setting on the Kenyan Coast. The MVT incorporated all of the above recommendations into its information-giving processes. The findings support the importance of community level information-giving and of giving information on several different occasions before seeking final individual consent. However, an emerging issue was that inter-personal interactions and relationships between researchers and community members, and within the community, play a critical role in participants' perceptions of a study, their decisions to consent or withdraw, and their advice to researchers on study practicalities and information to feedback at the end of the trial. These relationships are based on and continually tested by information-giving processes, and by context specific concerns and interests that can be difficult to predict and are well beyond the timescale and reach of single research activities. On the basis of these findings, we suggest that the current move towards increasingly ambitious and stringent formal standards for information-giving to individuals be counter-balanced with greater attention to the diverse social relationships that are essential to the successful application of these procedures. This may be assisted by emphasising respecting communities as well as persons, and by recognising that current guidelines and regulations may be an inadequate response to the complex, often unpredictable and ever shifting ethical dilemmas facing research teams working 'in the field'.