Nuffield Council on Bioethics responds to announcement of UK human challenge trials

In human challenge studies, participants are deliberately infected with the virus in question in order to gain knowledge in controlled circumstances about how the virus behaves, or in order to see if an investigational vaccine provides protection. Given the scale of the global challenges that COVID-19 poses, challenge trials could potentially play a useful role alongside the many other studies currently taking place. However, they come with their own unique set of ethical considerations and risks that must be addressed by all those involved in the study – a properly constituted ethics committee, researchers, and funders.

The World Health Organisation has published guidance on the issues that such a committee should consider – and also recommended that any proposed COVID challenge study should be reviewed by a specialist ethics committee with the necessary scientific and ethical expertise. We understand that the Health Research Authority has established such a specialist ethics committee in order to be prepared for any applications to run a challenge trial in the UK, and we warmly welcome the establishment of this committee.

Today’s announcement highlights an early stage of the human challenge trial process, and will require ethical approval before it goes ahead. Those involved in the developing the study model, and in any specific research proposal, must now consider the following:

• Scientific justification – is a challenge study the most appropriate approach? Can the same benefit be gained for lower risk in a different kind of study?
• Engagement with the wider public. Researchers and funders must consult and engage with the wider public from the beginning. They must make sure that public concerns are properly understood and addressed, and that anxieties based on misconceptions can be avoided.
• Assessment of risks and benefits – potential benefits must outweigh risks, taking into account the interests of three groups: participants, society in general, and third-party contacts of participants. Researchers and funders must consider what actions must be taken to minimise risks – such as finding an appropriate dose of the challenge virus – and mitigate those risks that remain, for example by determining which volunteers are highly unlikely to develop serious disease, how volunteers will be monitored, and ensuring they have access to the best possible care.
• Informed consent. There are significant challenges in ensuring volunteers thoroughly understand the risks and the uncertainty of any benefit. Volunteers will also be committing to stay within a biosecure facility until they are no longer infectious.

We hope they will involve a wide range of voices in considering how this might go forward.

Further information

For more information about human challenge trials and their unique ethical considerations, read Katharine Wright’s blog How ethically challenging are challenge trials? and Susan Tansey’s blog To challenge or not to challenge? That is the question!

To read more about conducting ethical research in global health emergencies and the responsibilities of all parties involved in research, read our report Research in global health emergencies: ethical issues.