Human infection challenge studies in endemic settings and/or low-income and middle-income countries: key points of ethical consensus and controversy

A scoping review of ethics review processes during public health emergencies in Africa

BACKGROUND

The COVID-19 pandemic forced governments, multilateral public health organisations and research institutions to undertake research quickly to inform their responses to the pandemic. Most COVID-19-related studies required swift approval, creating ethical and practical challenges for regulatory authorities and researchers. In this paper, we examine the landscape of ethics review processes in Africa during public health emergencies (PHEs).

METHODS

We searched four electronic databases (Web of Science, PUBMED, MEDLINE Complete, and CINAHL) to identify articles describing ethics review processes during public health emergencies and/or pandemics. We selected and reviewed those articles that were focused on Africa. We charted the data from the retrieved articles including the authors and year of publication, title, country and disease(s) reference, broad areas of (ethical) consideration, paper type, and approach.

RESULTS

Of an initial 4536 records retrieved, we screened the titles and abstracts of 1491 articles, and identified 72 articles for full review. Nine articles were selected for inclusion. Of these nine articles, five referenced West African countries including Liberia, Guinea and Sierra Leone, and experiences linked to the Ebola virus disease. Two articles focused on South Africa and Kenya, while the other two articles discussed more general experiences and pitfalls of ethics review during PHEs in Africa more broadly. We found no articles published on ethics review processes in Africa before the 2014 Ebola outbreak, and only a few before the COVID-19 outbreak. Although guidelines on protocol review and approval processes for PHEs were more frequently discussed after the 2014 Ebola outbreak, these did not focus on Africa specifically.

CONCLUSIONS

There is a gap in the literature about ethics review processes and preparedness within Africa during PHEs. This paper underscores the importance of these processes to inform practices that facilitate timely, context-relevant research that adequately recognises and reinforces human dignity within the quest to advance scientific knowledge about diseases. This is important to improve fast responses to PHEs, reduce mortality and morbidity, and enhance the quality of care before, during, and after pandemics.

Should Children Be Included in Human Challenge Studies?

Human challenge studies, in which human research subjects are intentionally exposed to pathogens to contribute to scientific knowledge, raise many ethical complexities. One controversial question is whether it is ethically permissible to include children as participants. Commentary of the past decades endorses the exclusion of children, while new guidance suggests that pediatric human challenge studies can be ethically permissible. This paper argues that neither children's exclusion nor their inclusion are well justified. I examine and reject three arguments for exclusion, but suggest that these arguments establish pediatric human challenge studies as a complex ethical category of research that requires caution. I then argue for a strong presumption against children's inclusion, by drawing on an analogy to children's inclusion in phase I trials, emphasizing a requirement of necessity, and suggesting that accommodating children's vulnerability promotes an age de-escalation approach for pediatric human challenge studies research. In the final section, I suggest a procedure for ethics review.

Ethical Requirements for Human Challenge Studies: A Systematic Review of Reasons

Human challenge studies (HCS) are controlled clinical trials in which participants are deliberately infected with a pathogen. Such trials are being developed for an increasing number of diseases. Partly as a result of the coronavirus disease 2019 (COVID-19) pandemic, there has been a recent ethical debate about the reasons for and against HCS in general, or rather, about the requirements that individual HCS must fulfill to be ethically acceptable. A systematic review was conducted to categorize and summarize such requirements and the reasons given for them. Ethics literature was searched in PubMed, Google Scholar, BELIT, and PhilPapers; eligibility criteria were articles published in a scientific/scholarly journal (original research, reviews, editorials, opinion pieces, and conference/meeting reports). Of 1,322 records identified, 161 publications were included, with 183 requirements (with associated reasons) in 10 thematic categories extracted via qualitative content analysis. In synthesizing and interpreting the requirements and their reasons, three issues emerge as particularly sensitive in the case of HCS: the meaning of the right to withdraw from research procedures, communication of researchers with the public and various stakeholders, and the conditions of informed consent. However, four other issues, not specific to HCS, stand out as the most controversial: the acceptable level of risk to participants, payment of participants, protection of vulnerable groups, and standards for international collaborations. Controversies in these areas indicate that further debate is warranted, possibly leading to more specific instructions in ethics guidance documents.

The Case for Human Challenge Trials in COVID-19

The COVID-19 pandemic has necessitated rapid research to aid in the understanding of the disease and the development of novel therapeutics. One option is to conduct controlled human infection trials (CHITs). In this article I examine the history of deliberate human infection and CHITs and their utilization prior to the COVID-19 pandemic, key ethical considerations of CHITs in the COVID-19 setting, an analysis of the World Health Organization's (WHO) Key criteria for the ethical acceptability of COVID-19 human challenge studies, and a review of the two COVID-19 CHITs that have already commenced, their compliance with the WHO criteria and other ethical considerations.

Perceptions and acceptability of the controlled human malaria infection (CHMI) model in The Gambia: a qualitative study

Controlled human malaria infection (CHMI) studies, i.e. the deliberate infection of healthy volunteers with malaria parasites to study immune response and/or test drug or vaccine efficacy, are increasingly being conducted in malaria endemic countries, including in sub-Saharan Africa. However, there have been few studies on the perceptions and acceptability of CHMI by the local communities. This qualitative study assessed the perception and acceptability of such studies in The Gambia following the first CHMI study conducted in the country in March-May 2018. Data were collected through non-participant observation, in-depth interviews and focus group discussions and analyzed using NVivo 12 software with an inductive-deductive approach. Sixty-seven participants were involved, including volunteers enrolled in the CHMI, community stakeholders and members of the Gambian Ethics Committee. Respondents expressed a positive view about CHMI. Key motivating factors for participation were the financial compensation, comprehensive health checks, and willingness to support malaria research. Risks associated with participation were considered low. Concerns raised included the frequency of bleeding and the blood volume collected.

Ethical and practical considerations arising from community consultation on implementing controlled human infection studies using Schistosoma mansoni in Uganda

Issues related to controlled human infection studies using Schistosoma mansoni (CHI-S) were explored to ensure the ethical and voluntary participation of potential CHI-S volunteers in an endemic setting in Uganda. We invited volunteers from a fishing community and a tertiary education community to guide the development of informed consent procedures. Consultative group discussions were held to modify educational materials on schistosomiasis, vaccines and the CHI-S model and similar discussions were held with a test group. With both groups, a mock consent process was conducted. Fourteen in-depth key informant interviews and three group discussions were held to explore perceptions towards participating in a CHI-S. Most of the participants had not heard of the CHI-S. Willingness to take part depended on understanding the study procedures and the consenting process. Close social networks were key in deciding to take part. The worry of adverse effects was cited as a possible hindrance to taking part. Volunteer time compensation was unclear for a CHI-S. Potential volunteers in these communities are willing to take part in a CHI-S. Community engagement is needed to build trust and time must be taken to share study procedures and ensure understanding of key messages.

Critical success factors for conducting human challenge trials for vaccine development in low- and middle-income countries

BACKGROUND

Owing to the globalization of vaccine clinical trials, as well as advances in technologies, improved research accountability, and robust regulatory and ethical scrutiny, the choice to perform human challenge trials has become evident, and one of the most significant applications of human challenge trials is the assessment of vaccine efficacy. While human challenge trials have largely been conducted in high-income countries, the concept is relatively new in many low- and middle-income countries. Thus, the aim of this study was to identify the critical success factors for conducting human challenge trials for vaccine development in low- and middle-income countries.

METHODOLOGY

Using a two-step methodology, we first carried out a systematic literature review that was centered on identifying low- and middle-income countries that are either establishing a framework for, have conducted, or are conducting human challenge trials for vaccine development; secondly, we conducted a descriptive cross-sectional survey using a standardized semi-structured online questionnaire administered to eligible stakeholders, to identify the critical success factors for conducting human challenge trials for vaccine development in low- and middle-income countries. Seventeen low- and middle-income countries were identified and included in the survey.

RESULTS

The most cited critical success factors for conducting human challenge trials for vaccine development in low- and middle-income countries were Informed Consent, Risk Compensation and/or Reimbursement, Participant Safety and/or Public Protection, Community Engagement, Infrastructural Capacity, and Ethical and Regulatory Frameworks.

CONCLUSION

From an empirical perspective, this study provides a list of critical success factors that form the basic structure to guide the design and implementation of further human challenge trials in low- and middle-income countries. Further studies are needed to establish a standardized conceptual framework to aid in the review, approval and overall conduct of human challenge trials in low- and middle-income countries.

Vaccines against leishmaniasis: using controlled human infection models to accelerate development

INTRODUCTION

Leishmaniasis is a neglected tropical disease that is defined by the World Health Organization as vaccine preventable. Although several new candidate vaccines are in development, no vaccine has successfully reached the market for human use. Several species of Leishmania cause human disease and have co-evolved with their respective sand fly vectors. These unique relationships have implications for initiation of infection and vaccine development. An approach to vaccine development for many infectious diseases is the use of controlled human infection models (CHIMs).

AREAS COVERED

We describe the history and recent development of experimental and deliberate infection using Leishmania in humans and the rationale for developing a new sand fly-initiated CHIM to progress leishmaniasis vaccine development. Examples from other infectious diseases are discussed in the context of the development of a new leishmaniasis CHIM. We also reflect upon the manufacture of the challenge agent, practical considerations, safety, ethics, and regulatory issues.

EXPERT OPINION

A new cutaneous Leishmania CHIM is being developed to enable testing of vaccines in the development pipeline. Questions remain about the use of such CHIMs to determine effectiveness of vaccines against visceral leishmaniasis. However, such a CHIM will be invaluable in expediting time to market for vaccines.

Engagement of ethics and regulatory authorities on human infection studies: Proceedings of an engagement workshop in Zambia

Human infection studies (HIS) have generally been used as a tool in the pathway for vaccine development in high income settings. Over the last decade, this model has been implemented in LMICs with the aim of accelerating development of next generation vaccines that would perform better in these settings. However, in most LMICs, the ethics and regulatory framework for the conduct of these studies are not in place. In Zambia, these studies are yet to be conducted and thus we conducted a stakeholder engagement workshop in October 2019. We engaged with bioethicists, regulatory authority officials, and scientists from within Zambia and other African countries to anticipate and address foreseeable ethical and regulatory issues when conducting HIS in Zambia for the first time. The workshop largely focused on sensitizing the stakeholders on the benefits of these studies with the following main points for consideration on the implementation of these studies in Zambia: need for in-country legal framework and guidelines; need for adequate informed consent based on comprehensive understanding of the concept of HIS and study requirements; and requirements for heightened vigilance to assure participant safety including good ethical and clinical practice with regulatory, ethical, data safety, and community oversight. Additionally, the workshop emphasized the need for rigorous health screening prior to enrolment; suitable infrastructure for containment; and personnel to provide appropriate treatment including emergency resuscitation and evacuation if indicated. Specific recommendations included compensation for burden of participation; access to care and provision for study related injury (e.g. no-fault insurance); and withdrawal and exit procedures to preserve individual and community safety. Finally, the meeting concluded that researchers should actively engage key gate keepers including civic leaders such as parliamentarians, universities, researchers, potential participants and laypersons to avoid circulation of misinformation.

Understanding the benefits and burdens associated with a malaria human infection study in Kenya: experiences of study volunteers and other stakeholders

BACKGROUND

Human infection studies (HIS) that involve deliberately infecting healthy volunteers with a pathogen raise important ethical issues, including the need to ensure that benefits and burdens are understood and appropriately accounted for. Building on earlier work, we embedded social science research within an ongoing malaria human infection study in coastal Kenya to understand the study benefits and burdens experienced by study stakeholders in this low-resource setting and assess the wider implications for future research planning and policy.

METHODS

Data were collected using qualitative research methods, including in-depth interviews (44), focus group discussions (10) and non-participation observation. Study participants were purposively selected (key informant or maximal diversity sampling), including volunteers in the human infection study, study staff, community representatives and local administrative authorities. Data were collected during and up to 18 months following study residency, from sites in Coastal and Western Kenya. Voice recordings of interviews and discussions were transcribed, translated, and analysed using framework analysis, combining data- and theory-driven perspectives.

FINDINGS

Physical, psychological, economic and social forms of benefits and burdens were experienced across study stages. Important benefits for volunteers included the study compensation, access to health checks, good residential living conditions, new learning opportunities, developing friendships and satisfaction at contributing towards a new malaria vaccine. Burdens primarily affected study volunteers, including experiences of discomfort and ill health; fear and anxiety around aspects of the trial process, particularly deliberate infection and the implications of prolonged residency; anxieties about early residency exit; and interpersonal conflict. These issues had important implications for volunteers' families, study staff and the research institution's reputation more widely.

CONCLUSION

Developing ethically and scientifically strong HIS relies on grounded accounts of volunteers, study staff and the wider community, understood in the socioeconomic, political and cultural context where studies are implemented. Recognition of the diverse, and sometimes perverse, nature of potential benefits and burdens in a given context, and who this might implicate, is critical to this process. Prior and ongoing stakeholder engagement is core to developing these insights.

Understanding the benefits and burdens associated with a malaria human infection study in Kenya: experiences of study volunteers and other stakeholders

Background

Human infection studies (HIS) that involve deliberately infecting healthy volunteers with a pathogen raise important ethical issues, including the need to ensure that benefits and burdens are understood and appropriately accounted for. Building on earlier work, we embedded social science research within an ongoing malaria human infection study in coastal Kenya to understand the study benefits and burdens experienced by study stakeholders in this low-resource setting and assess the wider implications for future research planning and policy.

Methods

Data were collected using qualitative research methods, including in-depth interviews (44), focus group discussions (10) and non-participation observation. Study participants were purposively selected (key informant or maximal diversity sampling), including volunteers in the human infection study, study staff, community representatives and local administrative authorities. Data were collected during and up to 18 months following study residency, from sites in Coastal and Western Kenya. Voice recordings of interviews and discussions were transcribed, translated, and analysed using framework analysis, combining data- and theory-driven perspectives.

Findings

Physical, psychological, economic and social forms of benefits and burdens were experienced across study stages. Important benefits for volunteers included the study compensation, access to health checks, good residential living conditions, new learning opportunities, developing friendships and satisfaction at contributing towards a new malaria vaccine. Burdens primarily affected study volunteers, including experiences of discomfort and ill health; fear and anxiety around aspects of the trial process, particularly deliberate infection and the implications of prolonged residency; anxieties about early residency exit; and interpersonal conflict. These issues had important implications for volunteers’ families, study staff and the research institution’s reputation more widely.

Conclusion

Developing ethically and scientifically strong HIS relies on grounded accounts of volunteers, study staff and the wider community, understood in the socioeconomic, political and cultural context where studies are implemented. Recognition of the diverse, and sometimes perverse, nature of potential benefits and burdens in a given context, and who this might implicate, is critical to this process. Prior and ongoing stakeholder engagement is core to developing these insights.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05455-7.

Immunological Considerations for Schistosoma Vaccine Development: Transitioning to Endemic Settings

Despite mass drug administration programmes with praziquantel, the prevalence of schistosomiasis remains high. A vaccine is urgently needed to control transmission of this debilitating disease. As some promising schistosomiasis vaccine candidates are moving through pre-clinical and clinical testing, we review the immunological challenges that these vaccine candidates may encounter in transitioning through the clinical trial phases in endemic settings. Prior exposure of the target population to schistosomes and other infections may impact vaccine response and efficacy and therefore requires considerable attention. Schistosomes are known for their potential to induce T-reg/IL-10 mediated immune suppression in populations which are chronically infected. Moreover, endemicity of schistosomiasis is focal whereby target and trial populations may exhibit several degrees of prior exposure as well as in utero exposure which may increase heterogeneity of vaccine responses. The age dependent distribution of exposure and development of acquired immunity, and general differences in the baseline immunological profile, adds to the complexity of selecting suitable trial populations. Similarly, prior or concurrent infections with other parasitic helminths, viral and bacterial infections, may alter immunological responses. Consequently, treatment of co-infections may benefit the immunogenicity of vaccines and may be considered despite logistical challenges. On the other hand, viral infections leave a life-long immunological imprint on the human host. Screening for serostatus may be needed to facilitate interpretation of vaccine responses. Co-delivery of schistosome vaccines with PZQ is attractive from a perspective of implementation but may complicate the immunogenicity of schistosomiasis vaccines. Several studies have reported PZQ treatment to induce both transient and long-term immuno-modulatory effects as a result of tegument destruction, worm killing and subsequent exposure of worm antigens to the host immune system. These in turn may augment or antagonize vaccine immunogenicity. Understanding the complex immunological interactions between vaccine, co-infections or prior exposure is essential in early stages of clinical development to facilitate phase 3 clinical trial design and implementation policies. Besides well-designed studies in different target populations using schistosome candidate vaccines or other vaccines as models, controlled human infections could also help identify markers of immune protection in populations with different disease and immunological backgrounds.

Back to WHAT? The role of research ethics in pandemic times

The Covid-19 pandemic creates an unprecedented threatening situation worldwide with an urgent need for critical reflection and new knowledge production, but also a need for imminent action despite prevailing knowledge gaps and multilevel uncertainty. With regard to the role of research ethics in these pandemic times some argue in favor of exceptionalism, others, including the authors of this paper, emphasize the urgent need to remain committed to core ethical principles and fundamental human rights obligations all reflected in research regulations and guidelines carefully crafted over time. In this paper we disentangle some of the arguments put forward in the ongoing debate about Covid-19 human challenge studies (CHIs) and the concomitant role of health-related research ethics in pandemic times. We suggest it might be helpful to think through a lens differentiating between risk, strict uncertainty and ignorance. We provide some examples of lessons learned by harm done in the name of research in the past and discuss the relevance of this legacy in the current situation.

Promoting Ethical Payment in Human Infection Challenge Studies

To prepare for potential human infection challenge studies (HICS) involving SARS-CoV-2, we convened a multidisciplinary working group to address ethical questions regarding whether and how much SARS-CoV-2 HICS participants should be paid. Because the goals of paying HICS participants, as well as the relevant ethical concerns, are the same as those arising for other types of clinical research, the same basic framework for ethical payment can apply. This framework divides payment into reimbursement, compensation, and incentives, focusing on fairness and promoting adequate recruitment and retention as counterweights to concerns about undue inducement. Within the basic framework, several factors are especially salient for HICS, and for SARS-CoV-2 HICS in particular, including the nature of participant confinement, anticipated discomfort, risks and uncertainty, participant motivations, and trust. These factors are reflected in a payment worksheet created to help sponsors, researchers, and ethics reviewers systematically develop and assess ethically justifiable payment amounts.

Engagement of ethics and regulatory authorities on human infection studies: Proceedings of an engagement workshop in Zambia

Human infection studies (HIS) have generally been used as a tool in the pathway for vaccine development in high income settings. Over the last decade, this model has been implemented in LMICs with the aim of accelerating development of next generation vaccines that would perform better in these settings. However, in most LMICs, the ethics and regulatory framework for the conduct of these studies are not in place. In Zambia, these studies are yet to be conducted and thus we conducted a stakeholder engagement workshop in October 2019. We engaged with bioethicists, regulatory authority, and scientists from within Zambia and other African countries to anticipate and address foreseeable ethical and regulatory issues when conducting HIS in Zambia for the first time. The workshop largely focused on sensitizing the stakeholders on the benefits of these studies with the following main points for consideration on the implementation of these studies in Zambia: need for in-country legal framework and guidelines; need for adequate informed consent based on comprehensive understanding of the concept of HIS and study requirements; and requirements for heightened vigilance to assure participant safety including good ethical and clinical practice with regulatory, ethical, data safety, and community oversight. Additionally, the workshop emphasized the need for rigorous health screening prior to enrolment; suitable infrastructure for containment; and personnel to provide appropriate treatment including emergency resuscitation and evacuation if indicated. Specific recommendations included compensation for burden of participation; access to care and provision for study related injury (e.g. no-fault insurance); and withdrawal and exit procedures to preserve individual and community safety. Finally, the meeting concluded that researchers should actively engage key gate keepers including civic leaders such as parliamentarians, universities, researchers, potential participants and laypersons to avoid circulation of misinformation.

"At first, I was very afraid"-a qualitative description of participants' views and experiences in the first Human Infection Study in Malawi

Background: Human infection studies (HIS) involve deliberately infecting healthy volunteers with a pathogen in a controlled environment to understand infection and support the development of effective vaccines or treatments. HIS research is expanding to many low and middle-income settings to accelerate vaccine development. Given the implementation of the first HIS research to establish the experimental human pneumococcal carriage model's feasibility, we sought to understand the participant's opinions and experiences. Methods: We used a qualitative, descriptive approach to understand participants perceptions and experiences on HIS participation. Sixteen healthy adult participants were invited to participate in in-depth exit interviews to discuss their experiences, motivations and concerns. Results: Our findings showed that the likelihood of participation in HIS research rests on three essential conditions: motivation to participate, compensation and advocacy. The motivation and decision to participate was based on reasons including altruism, patriotism, monetary and material incentives, and while compensation was deemed appropriate, concerns about unanticipated research-related risks were raised. Participant advocate groups were recommended for increasing awareness and educating others in the broader community about HIS research. Conclusions: Participants' experiences of HIS in Malawi provide the basis of what can be acceptable in HIS research in lower-income countries and areas where study procedures could be adjusted.

"At first, I was very afraid"-a qualitative description of participants' views and experiences in the first Human Infection Study in Malawi

Background: Human infection studies (HIS) involve deliberately infecting healthy volunteers with a pathogen in a controlled environment to understand infection and support the development of effective vaccines or treatments. HIS research is expanding to many low and middle-income settings to accelerate vaccine development. Given the implementation of the first HIS research to establish the experimental human pneumococcal carriage model's feasibility, we sought to understand the participant's opinions and experiences. Methods: We used a qualitative, descriptive approach to understand participants perceptions and experiences on HIS participation. Sixteen healthy adult participants were invited to participate in in-depth exit interviews to discuss their experiences, motivations and concerns. Results: Our findings showed that the likelihood of participation in HIS research rests on three essential conditions: motivation to participate, compensation and advocacy. The motivation and decision to participate was based on reasons including altruism, patriotism, monetary and material incentives, and while compensation was deemed appropriate, concerns about unanticipated research-related risks were raised. Participant advocate groups were recommended for increasing awareness and educating others in the broader community about HIS research. Conclusions: Participants' experiences of HIS in Malawi provide the basis of what can be acceptable in HIS research in lower-income countries and areas where study procedures could be adjusted.

Informed consent for controlled human infection studies in low- and middle-income countries: Ethical challenges and proposed solutions

In controlled human infection studies (CHIs), participants are deliberately exposed to infectious agents in order to better understand the mechanism of infection or disease and test therapies or vaccines. While most CHIs have been conducted in high-income countries, CHIs have recently been expanding into low- and middle-income countries (LMICs). One potential ethical concern about this expansion is the challenge of obtaining the voluntary informed consent of participants, especially those who may not be literate or have limited education. In some CHIs in LMICs, researchers have attempted to address this potential concern by limiting access to literate or educated populations. In this paper, we argue that this practice is unjustified, as it does not increase the chances of obtaining valid informed consent and therefore unfairly excludes illiterate populations and populations with lower education. Instead, we recommend that investigators improve the informed consent process by drawing on existing data on obtaining informed consent in these populations and interventions aimed at improving their understanding. Based on a literature review, we provide concrete suggestions for how to follow this recommendation and ensure that populations with lower literacy or education are given a fair opportunity to protect their rights and interests in the informed consent process.

SARS-CoV-2 (COVID-19) Vaccine Development and Production: An Ethical Way Forward

The world awaits a SARS-CoV-2 virus (i.e., COVID-19 disease) vaccine to keep the populace healthy, fully reopen their economies, and return their social and healthcare systems to “normal.” Vaccine safety and efficacy requires meticulous testing and oversight; this paper describes how despite grandiose public statements, the current vaccine development, testing, and production methods may prove to be ethically dubious, medically dangerous, and socially volatile. The basic moral concern is the potential danger to the health of human test subjects and, eventually, many vaccine recipients. This is further complicated by economic and political pressures to reduce government oversight on rushed vaccine testing and production, nationalistic distribution goals, and failure to plan for the widespread immunization needed to produce global herd immunity. As this paper asserts, the public must be better informed to assess promises about the novel vaccines being produced and to tolerate delays and uncertainty.