Shigella-Specific Immune Profiles Induced after Parenteral Immunization or Oral Challenge with Either Shigella flexneri 2a or Shigella sonnei.

Shigella spp. are a leading cause of diarrhea-associated global morbidity and mortality. Development and widespread implementation of an efficacious vaccine remain the best option to reduce Shigella-specific morbidity. Unfortunately, the lack of a well-defined correlate of protection for shigellosis continues to hinder vaccine development efforts. Shigella controlled human infection models (CHIM) are often used in the early stages of vaccine development to provide preliminary estimates of vaccine efficacy; however, CHIMs also provide the opportunity to conduct in-depth immune response characterizations pre- and postvaccination or pre- and postinfection. In the current study, principal-component analyses were used to examine immune response data from two recent Shigella CHIMs in order to characterize immune response profiles associated with parenteral immunization, oral challenge with Shigella flexneri 2a, or oral challenge with Shigella sonnei. Although parenteral immunization induced an immune profile characterized by robust systemic antibody responses, it also included mucosal responses. Interestingly, oral challenge with S. flexneri 2a induced a distinctively different profile compared to S. sonnei, characterized by a relatively balanced systemic and mucosal response. In contrast, S. sonnei induced robust increases in mucosal antibodies with no differences in systemic responses across shigellosis outcomes postchallenge. Furthermore, S. flexneri 2a challenge induced significantly higher levels of intestinal inflammation compared to S. sonnei, suggesting that both serotypes may also differ in how they trigger induction and activation of innate immunity. These findings could have important implications for Shigella vaccine development as protective immune mechanisms may differ across Shigella serotypes. IMPORTANCE Although immune correlates of protection have yet to be defined for shigellosis, prior studies have demonstrated that Shigella infection provides protection against reinfection in a serotype-specific manner. Therefore, it is likely that subjects with moderate to severe disease post-oral challenge would be protected from a homologous rechallenge, and investigating immune responses in these subjects may help identify immune markers associated with the development of protective immunity. This is the first study to describe distinct innate and adaptive immune profiles post-oral challenge with two different Shigella serotypes. Analyses conducted here provide essential insights into the potential of different immune mechanisms required to elicit protective immunity, depending on the Shigella serotype. Such differences could have significant impacts on vaccine design and development within the Shigella field and should be further investigated across multiple Shigella serotypes.

Less severe clinical symptoms of Norwalk virus 8fIIb inoculum compared to its precursor 8fIIa from human challenge studies.

Noroviruses (NoV) are a leading cause of epidemic gastroenteritis. Human challenge studies have been used to examine the infectivity, pathogenicity, and host immune response to NoV as well as vaccine efficacy. The goal of this study was to conduct a meta-analysis of data from five previously completed human challenge trials and compare the response to the secondary NV inoculum (8fIIb) to its precursor (8fIIa). We investigated a total of 158 subjects: 76 subjects were experimentally challenged with NV inoculum 8fIIa, and 82 subjects were challenged with 8fIIb. We compared demographic characteristics, infection, illness, mean severity score, blood types, and duration of viral shedding between the two groups of subjects. There were no statistically significant differences in overall infection and illness rates between subjects inoculated with 8fIIa and 8fIIb. However, individuals challenged with 8fIIa had significantly higher severity scores (5.05 vs. 3.22, p = .008) compared with those challenged with 8fIIb. We also observed that infection with 8fIIb was associated with significantly longer duration of viral shedding compared with 8fIIa (11.0 days vs. 5.0 days, p = .0005). These results have serious implications for the development of new NoV inocula for human challenge studies to test candidate vaccine efficacy-where illness severity and duration of viral shedding are important outcomes.

A roadmap for enterotoxigenic Escherichia coli vaccine development based on volunteer challenge studies.

Enterotoxigenic Escherichia coli (ETEC) is a major cause of travelers' diarrhea and of diarrhea among young children in developing countries. Experimental challenge studies in adult volunteers have played a pivotal role in establishing ETEC as an enteric pathogen, elucidating its pathogenesis by identifying specific virulence attributes, characterizing the human immune response to clinical and sub-clinical ETEC infection and assessing preliminarily the clinical acceptability, immunogenicity and efficacy of prototype ETEC vaccines. This review provides a historical perspective of experimental challenge studies with ETEC. It summarizes pioneering early studies carried out by investigators at the University of Maryland School of Medicine to show how those studies provided key information that influenced the directions taken by many research groups to develop vaccines to prevent ETEC. In addition, key experimental challenge studies undertaken at other institutions will also be cited.

Analysis of the first 2645 registrations at the research registry®: A global repository for all study types involving human participants.

BACKGROUND: The Declaration of Helsinki has called for the registration of all research studies involving human participants. Despite this, prior registries did not allow registration certain study types, or retrospective registration. The Research Registry® (www.researchregistry.com) was established in 2015 to provide a venue of registration for any study involving human participants. METHODS: and analysis: This retrospective database analysis describes the first 3000 registrations received by the Research Registry®. Since the launch of the Registry in 2015, we have collected data on each registration and excluded inappropriate registrations through a weekly curation process. The characteristics of all studies registered is presented. Each registration was marked against a quality score by two researchers acting independently, and we describe how this has changed over time. No ethical approval was required for this data only study including no human participants. RESULTS: Of 3000 registrations, we included 2645 that were submitted to the registry between February 2015 and October 2017. The number of registrations increased year on year, and we now receive between 60 and 80 registrations per month. One fifth of registrations were from China (537 [20.3%]). Retrospective observational studies were most commonly registered (1125 [42.5%]), and studies included in excess of 20 million patients (median 80 [IQR:25-200]). The quality score of registrations improved over the time (Kruskal-Wallis p < 0.05), and the 'control/comparator' component of the quality score was most poorly completed (completed by 1199 [54%]). CONCLUSION: The Research Registry® has received registrations on over 2500 registrations, including in excess of 20 million patients, with the quality of registrations improving over time. Retrospective observational studies and case series are the most commonly registered.

Controlled human infections: A report from the controlled human infection models workshop, Leiden University Medical Centre 4-6 May 2016.

The principle of deliberately infecting humans with infectious agents in a controlled setting, so-called controlled human infections (CHI), is not novel. Many CHI models have a long history and were established decades ago such as the intentional exposure to yellow fever and dengue performed in the 1900's (Reed, 1902) [2]. In these times bioethics and scientific reasoning were in their infancy. Nowadays, clinical trials are highly regulated and CHI are executed worldwide. Controlled human malaria infections and influenza infections are the two most frequently practiced. Others are experiencing a revival or are being carefully developed. Because CHI models test the efficacy of promising vaccine or drug candidates early in clinical development, they offer the potential to decrease the number of failing phase 2 and 3 trials, reducing risks for patients and saving costs and efforts. In addition, CHI models provide unprecedented opportunities to dissect the physiological, immunological and metabolic changes that occur upon infection. However, it is clear that controlled infections require careful deliberation of safety, ethics, quarantine, scientific output and the production of infectious material. An independent international workshop was hosted by the Leiden University Medical Centre in The Netherlands, bringing together clinical investigators, basic scientists, regulators, funders and policy makers from 22 different countries to discuss the opportunities and challenges in CHI. The aim of the workshop was to discuss CHI as a tool to advance science, drug and vaccine development, share the challenges of establishing a CHI model with specific focus on neglected tropical diseases and the possibilities to transfer models to endemic sites. Noticeably, among the 128 participants were clinical investigators from ten different countries in Sub-Saharan Africa. An important dimension of the meeting was to give the floor to young established clinicians and scientists to voice their perspective on the future of CHI models.

Munich anatomy and the distribution of bodies from the Stadelheim execution site during National Socialism.

During the reign of National Socialism (NS) anatomical institutes regularly received bodies of executed prisoners in steadily increasing numbers. After 1939, the execution site at Stadelheim prison in Munich supplied not only Munich anatomy but also the institutes in Erlangen, Innsbruck and Würzburg. Due to the disappearance of the Munich body journals, the exact dimension and procedure of body procurement from Stadelheim remained unknown for 70 years. After consultation of a wide range of sources, including rediscovered fragments of the body journals, it is now possible to give an almost comprehensive account of the developments. This article deals with the attempts at recovering information on body procurement from Stadelheim prison during the NS period, which already indicated the significance of Munich anatomy in organizing the distribution of bodies. Thereafter, it addresses the number and distinct groups of Stadelheim prisoners, executed and delivered to the four anatomical institutes, the differences in the handling of their bodies, and the extent to which in particular Munich anatomy profited from the massive increase in executions. Finally, it unveils the role of the Munich Anatomical Institute in distributing those bodies among the anatomies during the Second World War, making it not only the main beneficiary but also the interim center of this process.

Nazi Medical Research in Neuroscience: Medical Procedures, Victims, and Perpetrators.

Issues relating to the euthanasia killings of the mentally ill, the medical research conducted on collected body parts, and the clinical investigations on living victims under National Socialism are among the best-known abuses in medical history. But to date, there have been no statistics compiled regarding the extent and number of the victims and perpetrators, or regarding their identities in terms of age, nationality, and gender. "Victims of Unethical Human Experiments and Coerced Research under National Socialism," a research project based at Oxford Brookes University, has established an evidence-based documentation of the overall numbers of victims and perpetrators through specific record linkages of the evidence from the period of National Socialism, as well as from post-WWII trials and other records. This article examines the level and extent of these unethical medical procedures as they relate to the field of neuroscience. It presents statistical information regarding the victims, as well as detailing the involvement of the perpetrators and Nazi physicians with respect to their post-war activities and subsequent court trials.

Impact of Open Data Policies on Consent to Participate in Human Subjects Research: Discrepancies between Participant Action and Reported Concerns.

Research outlets are increasingly adopting open data policies as a requisite for publication, including studies with human subjects data. We investigated whether open data policies influence participants' rate of consent by randomly assigning participants to view consent forms with and without discussion of open data policies. No participants declined to participate, regardless of condition, nor did rates of drop-out vs. completion vary between conditions. Furthermore, no significant change in potential consent rates was reported when participants were openly asked about the influence of open data policies on their likelihood of consent. However, follow-up analyses indicated possible poor attention to consent forms, consistent with previous research. Moreover, thematic analysis of participants' considerations of open data policy indicated multiple considerations such as concerns regarding confidentiality, anonymity, data security, and study sensitivity. The impact of open data policies on participation raises complex issues at the intersection of ethics and scientific innovation. We conclude by encouraging researchers to consider participants as stakeholders in open data policy and by providing recommendations for open data policies in human subjects research.

Unsuccessful trial accrual and human subjects protections: an empirical analysis of recently closed trials.

BACKGROUND: Ethical evaluation of risk-benefit in clinical trials is premised on the achievability of resolving research questions motivating an investigation. OBJECTIVE: To determine the fraction and number of patients enrolled in trials that were at risk of not meaningfully addressing their primary research objective due to unsuccessful patient accrual. METHODS: We used the National Library of Medicine clinical trial registry to capture all initiated phases 2 and 3 intervention clinical trials that were registered as closed in 2011. We then determined the number that had been terminated due to unsuccessful accrual and the number that had closed after less than 85% of the target number of human subjects had been enrolled. Five factors were tested for association with unsuccessful accrual. RESULTS: Of 2579 eligible trials, 481 (19%) either terminated for failed accrual or completed with less than 85% expected enrolment, seriously compromising their statistical power. Factors associated with unsuccessful accrual included greater number of eligibility criteria (p = 0.013), non-industry funding (25% vs 16%, p < 0.0001), earlier trial phase (23% vs 16%, p < 0.0001), fewer number of research sites at trial completion (p < 0.0001) and at registration (p < 0.0001), and an active (non-placebo) comparator (23% vs 16%, p < 0.001). CONCLUSION: A total of 48,027 patients had enrolled in trials closed in 2011 who were unable to answer the primary research question meaningfully. Ethics bodies, investigators, and data monitoring committees should carefully scrutinize trial design, recruitment plans, and feasibility of achieving accrual targets when designing and reviewing trials, monitor accrual once initiated, and take corrective action when accrual is lagging.

Incidental computer tomography radiologic findings through research participation in the North Texas Healthy Heart Study.

BACKGROUND: Although variation exists in the classification and practice of managing clinical findings in research, emerging views suggest that researchers bear some responsibility in the management of incidental findings. This study contributes to the documentation of the population characteristics and prevalence of medical findings incidental to research participation, specifically findings related to coronary calcium scores and computed tomography (CT) scans that investigated cardiovascular disparities in an asymptomatic population. METHODS: A total of 571 asymptomatic adult participants were recruited in the North Texas Healthy Heart Study. Participants completed a 16-slice CT scan of the heart and abdomen. Findings of radiology reports and 3 years of follow-up documentation were reviewed. RESULTS: A total of 246 clinically apparent findings were identified in 169 asymptomatic participants (32.9% of participants who completed a CT scan). Another 245 participants (48%) had findings of unknown significance, a total of 307 findings. At least 4 cases in this study led to a clinically significant intervention. CONCLUSION: Although CT scans were completed for research purposes, study procedures resulted in the diagnosis and treatment of individuals who were previously asymptomatic. Potential clinical benefits in imaging research are moderated by considerations regarding possible harm and costs resulting from uncertain findings and the use of CT scans for nonclinical purposes. The continued development of protocols for the handling of incidental findings in research and the establishment of guidelines are needed to ensure that research procedures mirror the best interests of participants.

Participation of women and sex analyses in late-phase clinical trials of new molecular entity drugs and biologics approved by the FDA in 2007-2009.

BACKGROUND: Biological sex differences may contribute to differential treatment outcomes for therapeutic products. This study tracks women's participation in late-phase clinical trials (LPCTs), where efficacy and safety of drugs and biologics are evaluated, of new molecular entity (NME) drugs and biologics approved by the U.S. Food and Drug Administration (FDA) in 2007-2009. Furthermore, presentations of sex-based analyses were assessed from the FDA reviews. METHODS: New drug applications (NDAs) and biologics license applications (BLAs) were accessed from the U.S. FDA database and evaluated for women's participation in LPCTs. Sex-based analyses for efficacy and safety contained in FDA reviews were surveyed. Ratios for women's LPCT participation (PROPORTION OF STUDY SUBJECTS) to their proportion in the disease population were calculated for each approved therapeutic product and grouped into therapeutic categories. RESULTS: Sex-specific (n=5) and pediatric (n=3) drug applications were excluded. Women's participation in LPCTs was 39%, 48%, and 42% in NDAs (n=50) and 49%, 62%, and 58% in BLAs (n=11) for 2007, 2008, and 2009, respectively. Sixty-four percent of NDAs and 91% of BLAs had participation to proportion ratios of ≥0.80. Seventy-four percent of NDA reviews and 64% of BLA reviews included safety and efficacy sex analysis. Ninety-six percent of NDA reviews and 100% of BLA reviews included efficacy sex analysis. CONCLUSION: Women's participation in LPCTs averaged 43% for NDAs and 57% for BLAs in 2007-2009 and varied widely by indication. As a comparison, the 2001 U.S. Government Accountability Office (GAO) reported 52% of women's participation for drug clinical trials in1998-2000 and an FDA study reported 45% for BLAs approved from 1995 to 1999. This study showed that sex-analysis of both safety and efficacy in NDA has increased to 74% since the GAO report of 72%, while those for BLAs increased to 64% from 37% reported for therapeutic biologics approved in 1995-1999. Knowledge of disease prevalence and participation in clinical trials provides an understanding of recruitment and retention patterns of patients in these trials.

Motives for participating in a clinical research trial: a pilot study in Brazil.

BACKGROUND: In the past, clinical study participants have suffered from the experiments that they were subjected to. Study subjects may not understand the study process or may participate in clinical studies because they do not have access to medical care. The objectives of the present study were 1. to analyze the motives that might cause a volunteer to participate as a study subject; 2. to identify the social-demographic profile of this study subjects; and 3. to determine whether the motives to volunteer as a study subject are in accordance with the established legal and ethical principles for research in Brazil. METHODS: Mixed-methods research was used (a qualitative-quantitative approach). A sample of 80 volunteers underwent a semi-structured interview, which was based on a survey script that was elaborated from discussions with key informants. The sample was randomly selected from a database of clinical study volunteers that was provided by Brazilian clinical study centers. The interviews were recorded and transcribed. Descriptive statistics were used for content analysis, including contingency tables with hypothesis testing. RESULTS: The motivations for clinical study participation were linked to types of benefit. The most frequently encountered motivations were financial gain and therapeutic alternative. Altruism was not a common motivator, and when altruism was present, it was observed as a secondary motivator. All participants reported that they understood the Informed Consent Statement (ICS). However, only two parts of the form were remembered by all of the volunteers: the section on being able to leave the study at any point and the section that stated that there would be some responsible professional at their disposal for the entirety of the study. CONCLUSIONS: The present study shows that study participants are primarily motivated by personal benefit when volunteering to participate in clinical studies. Whether these study participants had an integral understanding of the ICS is not clear.

Socioeconomic determinants associated with willingness to participate in medical research among a diverse population.

INTRODUCTION: Although it is federally-mandated that racial/ethnic minorities be included in research studies, recruiting diverse populations remains a challenge. This is particularly difficult when research involves children. The purpose of this study was to assess attitudes and beliefs toward medical research among a racially and socioeconomically diverse population of parents of school children. METHODS: A cross-sectional parent-report survey was conducted in New York City public elementary schools using stratified random selection to obtain a diverse population. Fear of medical research and likelihood to participate in medical research were assessed using a validated questionnaire. Differences in fear/likelihood to participate in research across race/ethnicity and socioeconomic characteristics were evaluated. RESULTS: In general, parents were afraid of their child "being treated as a guinea pig", but were willing to allow their child to participate in research if asked by their own doctor. Factors associated with a lower score on fear toward research were; primary language other than English (OR=0.59), access to an interpreter (OR=0.73) and access to medical service within a day (OR=0.51). Latinos had the highest fear score (OR=1.87) compared to Whites. Asians were the ethnic group most likely to participate in research (OR=1.71). Low education level (OR=2.18) and public health insurance (OR=1.37) were associated with a higher score for likelihood of allowing one's child to participate in medical research. CONCLUSION: Minority parents reported more fear of allowing their children to participate in medical research, but were as likely to consent their children's participation, especially if asked by their own physician.