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In human challenge trials (HCTs), volunteers are deliberately infected with an infectious agent. Such trials can be used to accelerate vaccine development and answer important scientific questions. Starting early in the COVID-19 pandemic, ethical concerns were raised about using HCTs to accelerate development and approval of a vaccine. Some of those concerns pertained to potential exploitation of and/or lack of truly informed consent from volunteers. Specific areas of concern arose around individuals who may be unusually risk-seeking or too economically vulnerable to refuse the payments these trials provide, as opposed to being motivated primarily by altruistic goals. This pre-registered study is the first large-scale survey to characterize people who, early in the pandemic, expressed interest and intention to volunteer to participate in COVID-19 HCTs. We found that individuals expressing interest in SARS-CoV-2 HCTs exhibit consistently altruistic motivations without any special indication of poor risk perception or economic vulnerability. In finding that, early in the pandemic, COVID-19 HCTs were able to attract volunteers whose values align with the nature of these trials, and who are not unusually vulnerable to exploitation, this study may allay some ethical concerns about the volunteers interested in participating in such trials. [ABSTRACT FROM AUTHOR]

Author(s): Rebecca Kahn 1, Annette Rid 2, Peter G. Smith 3, Nir Eyal 4, Marc Lipsitch 1,5,* Summary points The 2014-2016 Ebola epidemic highlighted variations in the design of randomized [...]

Background: Participation in longitudinal research studies in resource-limited settings often involves frequent interactions with study staff and other participants, as well as receipt of incentives and transportation reimbursements. Social support—receipt of material and emotional resources from one's social network—has been linked to antiretroviral adherence in sub-Saharan Africa. The extent to which social support arises from study participation, its range and depth, and its implications for observational study conduct, have not been extensively described. Methods: We conducted individual open-ended and semi-structured interviews with participants in a longitudinal, observational antiretroviral therapy adherence monitoring study in Mbarara, Uganda. Participants were asked about their experiences in the longitudinal study and their interactions with research staff. We also interviewed study research assistants (RAs). Deductive and inductive coding were used to identify content related to the experience of study participation. Codes were organized into themes, and relationships between themes were used to develop overarching categories. Results: Sixty longitudinal study participants and 6 RAs were interviewed. Instrumental and emotional social support emerged as pervasive and valued aspects of longitudinal study participation. Instrumental support that participants received consisted of enhanced linkage to medical care, health education, and direct and indirect material benefits. Emotional support consisted of perceptions of feeling "cared for" and social interactions that permitted escape from HIV-related stigma. Both instrumental and emotional support often arose through the close relationships participants formed with research staff and with each other. Study-derived social support motivated some participants to adhere to antiretroviral therapy—an unanticipated effect potentially influencing the longitudinal study's primary observational outcome. Conclusions: Longitudinal study participation resulted in instrumental and emotional social support for participants. The depth of support participants experienced has implications for observational study design in resource-limited settings, including need to assess potential effects on study outcomes; consideration of social support during risk/benefit assessment in study ethics review and consent; and vigilance for consequences of social support loss when studies end. [ABSTRACT FROM AUTHOR]

We thank Richard Hayes and colleagues for their commentary [1] on our PLOS Medicine article [2]. We share the desire to learn through rigorous research whether HIV treatment-as-prevention (TasP) works [...]

New Guidelines In June 2013, the WHO issued new guidelines for antiretroviral treatment (ART). The guidelines substantially expand eligibility for ART, recommending initiation at CD4 cell counts [less than or [...]

Background: During the Ebola virus disease (EVD) epidemic in Liberia, contact tracing was implemented to rapidly detect new cases and prevent further transmission. We describe the scope and characteristics of contact tracing in Liberia and assess its performance during the 2014–2015 EVD epidemic. Methodology/Principal findings: We performed a retrospective descriptive analysis of data collection forms for contact tracing conducted in six counties during June 2014–July 2015. EVD case counts from situation reports in the same counties were used to assess contact tracing coverage and sensitivity. Contacts who presented with symptoms and/or died, and monitoring was stopped, were classified as “potential cases”. Positive predictive value (PPV) was defined as the proportion of traced contacts who were identified as potential cases. Bivariate and multivariate logistic regression models were used to identify characteristics among potential cases. We analyzed 25,830 contact tracing records for contacts who had monitoring initiated or were last exposed between June 4, 2014 and July 13, 2015. Contact tracing was initiated for 26.7% of total EVD cases and detected 3.6% of all new cases during this period. Eighty-eight percent of contacts completed monitoring, and 334 contacts were identified as potential cases (PPV = 1.4%). Potential cases were more likely to be detected early in the outbreak; hail from rural areas; report multiple exposures and symptoms; have household contact or direct bodily or fluid contact; and report nausea, fever, or weakness compared to contacts who completed monitoring. Conclusions/Significance: Contact tracing was a critical intervention in Liberia and represented one of the largest contact tracing efforts during an epidemic in history. While there were notable improvements in implementation over time, these data suggest there were limitations to its performance—particularly in urban districts and during peak transmission. Recommendations for improving performance include integrated surveillance, decentralized management of multidisciplinary teams, comprehensive protocols, and community-led strategies. [ABSTRACT FROM AUTHOR]