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Despite their clearly demonstrated safety and effectiveness, approved vaccines against COVID-19 are commonly mistrusted. Nations should find and implement effective ways to boost vaccine confidence. But the implications for ethical vaccine development are less straightforward than some have assumed. Opponents of COVID-19 vaccine challenge trials, in particular, made speculative or empirically implausible warnings on this matter, some of which, if applied consistently, would have ruled out most COVID-19 vaccine trials and many non-pharmaceutical responses., Competing Interests: Competing interests: NE serves on the Advisory Board of challenge trial volunteer organisation 1DaySooner (a non-profit promoting human challenge trials in COVID-19), an unpaid position., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Sometimes, offering someone beneficial care is likely to thwart the similar or more serious medical needs of more people. For example, when acute shortage is strongly predicted to persist, providing the long period on scarce intensive care that a certain COVID-19 patient needs is sometimes projected to block several future COVID-19 patients from receiving the shorter periods on intensive care that they will need. Expected utility is typically higher if the former is denied intensive care. A tempting initial account of such cases is that consequentialism supports denying care to that patient and nonconsequentialism supports providing that care. This paper argues that the consequentialist case is more complicated than it may initially seem and that nonconsequentialism sides more readily with denial of the beneficial treatment. It also shows that when denying it would directly enhance public health by a lot, either ethical approach would normally recommend denying it. Practical implications are discussed, including how to address conscientious objection to this shared recommendation., (© 2023 The Authors. Bioethics published by John Wiley & Sons Ltd.)

In many countries, the COVID-19 pandemic varied starkly between different racial and ethnic groups. Before vaccines were approved, some considered assigning priority access to worse-hit racial groups. That debate can inform rationing in future pandemics and in some of the many areas outside COVID-19 that admit of racial health disparities. However, concerns were raised that "race-responsive" prioritizations would be ruled unlawful for allegedly constituting wrongful discrimination. This legal argument relies on an understanding of discrimination law as demanding color-blindness. We argue that a, color-blind understanding of discrimination would be hostile only to one of two rationales for prioritizing the relevant racial minorities in settings of racial health disparities. We also propose a method for incorporating appropriate race-responsive concerns that is in many ways ethically and legally superior to ones suggested thus far. That method turns artificial intelligence, thanks precisely to its artificial and "black box" nature (features that underlie recent concerns about artificial intelligence's discriminatory potential), into an instrument of social justice., (© 2023 The Authors. Bioethics published by John Wiley & Sons Ltd.)

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., Competing Interests: The authors have read the journal’s policy and have the following competing interests: SMR and VS were employees of 1Day Sooner at the time of this study. JM is a current employee of 1Day Sooner. NE and AAM are on the Board of Advisors for 1Day Sooner. This does not alter our adherence to PLOS ONE policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare.

Notwithstanding the success of conventional field trials for vaccines against COVID-19, human challenge trials (HCTs) that could obtain more information about these and about other vaccines and further strategies against it are about to start in the UK. One critique of COVID-19 HCTs is their distinct paucity of information on crucial population groups. For safety reasons, these HCTs will exclude candidate participants of advanced age or with comorbidities that worsen COVID-19, yet a vaccine should (perhaps especially) protect such populations. We turn this cliché on its head. The truth is that either an HCT or a field trial has intrinsic generalisability limitations, that an HCT can expedite protection of high-risk participants even without challenging them with the virus, and that an important route to obtaining results generalisable to high-risk groups under either strategy is facilitated by HCTs., Competing Interests: Competing interests: NE serves on the Board of Advisor of 1DaySooner, an unpaid position., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

In high-income countries that were first to roll out coronavirus disease 2019 (COVID-19) vaccines, older adults have thus far usually been prioritized for these vaccines over younger adults. Age-based priority primarily resulted from interpreting evidence available at the time, which indicated that vaccinating the elderly first would minimize COVID-19 deaths and hospitalizations. The World Health Organization counsels a similar approach for all countries. This paper argues that some low- and middle-income countries that are short of COVID-19 vaccine doses might be justified in revising this approach and instead prioritizing certain younger persons when allocating current vaccines or future variant-specific vaccines., Competing Interests: Potential conflicts of interest. N. E. received payment or honoraria from Oxford University Press and held an unpaid, volunteer position with 1 Day Sooner. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Individual informed consent is a central requirement for clinical research on human subjects, yet whether and how consent requirements should apply to health policy experiments (HPEs) remains unclear. HPEs test and evaluate public health policies prior to implementation. We interviewed 58 health experts in Tanzania, Bangladesh and Germany on informed consent requirements for HPEs. Health experts across all countries favored a strong evidence base, prior information to the affected populations, and individual consent for 'risky' HPEs. Differences pertained to individual risk perception, how and when consent by group representatives should be obtained and whether HPEs could be treated as health policies. The study adds to representative consent options for HPEs, yet shows that more research is needed in this field - particularly in the present Covid-19 pandemic which has highlighted the need for HPEs nationally and globally.

Two years into the coronavirus disease 2019 (COVID-19) pandemic and following several hot debates, the world's first COVID-19 human challenge trial has recently been published by Killingley et al. We review its findings and explain why this particular juncture in time makes additional challenge trials for COVID-19 and for other diseases justified and important., Competing Interests: Declaration of interests N.E. serves on the Board of Advisors of 1Day Sooner, an unpaid position. He declares having no financial conflicts of interest. A.R. reports affiliation with 1Day Sooner throughout the writing of the article., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Early into COVID, human challenge trials were considered, but usually as alternatives to conventional randomized controlled trials. Instead, assessment of authorized COVID vaccines, of further COVID vaccines, and of vaccines against future pandemics should combine both designs, in five different ways, including a wholly novel one that we elaborate, Viz., combining data from both designs to answer a single question., (© 2022 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd.)

The world's first coronavirus disease 2019 human challenge trial using the D614G strain of severe acute respiratory syndrome 2 (SARS-CoV-2) is underway in the United Kingdom. The Wellcome Trust is funding challenge stock preparation of the Beta and Delta variant for a follow-up human challenge trial, and researchers at hVIVO are considering conducting these trials. However, little has been written thus far about the ethical justifiability of human challenge trials with SARS-CoV-2 variants of concern. We explore 2 specific characteristics of some variants that may initially be thought to make such trials unethical and conclude that SARS-CoV-2 variant challenge trials can remain ethical., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Although vaccines against severe acute respiratory syndrome coronavirus 2 have now been found safe and efficacious, there remains an urgent global health need to test both these vaccines and additional vaccines against the same virus. Under variable conditions, either standard or unusual designs would for both familiar and often-missed reasons make continued testing possible and ethical., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

In spring, summer and autumn 2020, one abiding argument against controlled human infection (CHI) studies of SARS-CoV-2 vaccines has been their impact on local communities. Leading scientists and bioethicists expressed concern about undue usage of local residents' direly needed scarce resources at a time of great need and even about their unintended infection. They recommended either avoiding CHI trials or engaging local communities before conducting any CHIs. Similar recommendations were not made for the alternative-standard phase III field trials of these same vaccines. We argue that the health effects of CHI studies on local residents not participating in the study tend to be smaller and more positive than those of field trials. That is all the more so now that tested vaccines are being rolled out. Whether or not local community engagement is necessary for urgent vaccine studies in the pandemic, the case for its engagement is stronger prior to field trials than prior to CHI studies., Competing Interests: Competing interests: NE serves on the advisory board for challenge trial intended-volunteer group 1DaySooner, an unpaid position., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. NE declares that he serves on the board of advisors for challenge volunteer organization 1Day Sooner--an unpaid position.

The design of human challenge studies balances scientific validity, efficiency and study safety. This Perspective explores some advantages and disadvantages of 'low-dosage' challenge studies, in the setting of testing second-generation vaccines against COVID-19. Compared with a conventional vaccine challenge, a low-dosage vaccine challenge would be more likely to start, and start earlier. A low-dosage challenge would also be less likely to rule out a vaccine candidate that would have potentially been effective, particularly in certain target uses. A key ethical advantage of a low-dosage challenge over a conventional challenge is that both it and its dose escalation process are safer for each participant. Low-dosage studies would require larger numbers of participants than conventional challenges, but this and other potential disadvantages are less serious than they may initially appear. Overall, low-dosage challenges should be considered for certain roles such as prioritizing between second-generation vaccines against COVID-19., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: A vaccine trial with a conventional challenge design can be very fast once it starts, but it requires a long prior process, in part to grow and standardize challenge virus in the laboratory. This detracts somewhat from its overall promise for accelerated efficacy testing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine candidates, and from the ability of developing countries and small companies to conduct it., Aims: We set out to identify a challenge design that avoids this part of the long prior process., Sources: Literature in trial design (including a proof of concept flu challenge trial by B. Killingley et al.), vaccinology, medical ethics, and various aspects of COVID response., Content: A challenge design with deliberate natural viral exposure avoids the need to grow culture. This new design is described and compared both to a conventional challenge design and to a conventional phase III field trial. In comparison, the proposed design has ethical, scientific, and feasibility strengths., Implications: The proposed new design should be considered for future vaccine trials., (Copyright © 2021 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

A vaccine for COVID-19 is urgently needed. Several vaccine trial designs may significantly accelerate vaccine testing and approval, but also increase risks to human subjects. Concerns about whether the public would see such designs as ethical represent an important roadblock to their implementation; accordingly, both the World Health Organization and numerous scholars have called for consulting the public regarding them. We answered these calls by conducting a cross-national survey (n = 5920) in Australia, Canada, Hong Kong, New Zealand, South Africa, Singapore, the United Kingdom, and the United States. The survey explained key differences between traditional vaccine trials and two accelerated designs: a challenge trial or a trial integrating a Phase II safety and immunogenicity trial into a larger Phase III efficacy trial. Respondents' answers to comprehension questions indicate that they largely understood the key differences and ethical trade-offs between the designs from our descriptions. We asked respondents whether they would prefer scientists to conduct traditional trials or one of these two accelerated designs. We found broad majorities prefer for scientists to conduct challenge trials (75%) and integrated trials (63%) over standard trials. Even as respondents acknowledged the risks, they perceived both accelerated trials as similarly ethical to standard trial designs. This high support is consistent across every geography and demographic subgroup we examined, including vulnerable populations. These findings may help assuage some of the concerns surrounding accelerated designs., Competing Interests: Declaration of Competing Interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

To counter the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), some have proposed accelerating SARS-CoV-2 vaccine development through controlled human infection (or 'challenge') trials. These trials would involve the deliberate exposure of relatively few young, healthy volunteers to SARS-CoV-2. We defend this proposal against the charge that there is still too much uncertainty surrounding the risks of COVID-19 to responsibly run such a trial., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

The article discusses that the WHO Working Group for Guidance on Human Challenge Studies in COVID-19 released a report according to which well-designed challenge studies could accelerate COVID-19 vaccine development, and delineated criteria which would suffice for them to remain ethical. It mentions that the ideas that follow build upon the pioneering effort undertaken throughout the course of the AIDS epidemic.

Human challenge trials to test the efficacy of vaccine candidates against SARS‐CoV‐2, the novel coronavirus behind Covid‐19, could save considerable time and many lives. But they may initially seem unethical because they expose healthy volunteers to a live virus that is killing many people and for which no cure exists. This article argues that this is not the correct test of their ethics. The correct test is comparative. And in the special circumstances of the Covid‐19 pandemic, human challenge trials meet the correct test better than standard efficacy testing would. [ABSTRACT FROM AUTHOR]

Controlled human challenge trials of SARS-CoV-2 vaccine candidates could accelerate the testing and potential rollout of efficacious vaccines. By replacing conventional phase 3 testing of vaccine candidates, such trials may subtract many months from the licensure process, making efficacious vaccines available more quickly. Obviously, challenging volunteers with this live virus risks inducing severe disease and possibly even death. However, we argue that such studies, by accelerating vaccine evaluation, could reduce the global burden of coronavirus-related mortality and morbidity. Volunteers in such studies could autonomously authorize the risks to themselves, and their net risk could be acceptable if participants comprise healthy young adults, who are at relatively low risk of serious disease following natural infection, if they have a high baseline risk of natural infection, and if during the trial they receive frequent monitoring and, following any infection, the best available care. [ABSTRACT FROM AUTHOR]