The UK Pandemic Ethics Accelerator and non-profit organization 1Day Sooner has released a new report titled “Ethics of Challenge Studies in Mitigating Pandemic Risks”. The report examines controlled human infection models (CHIMs), also known as human challenge studies, in the context of a pandemic.
In a CHIM model, a healthy human volunteer is deliberately infected with a pathogen under controlled conditions. This is done to accelerate the development of a vaccine or drug and increase knowledge about the disease.
The authors of the report specified a list of potential pandemic pathogens (PPPs), such as MERS, Dengue, Chikungunya, and Disease X, a placeholder name for a future pandemic. Due to climate change and increased interactions between humans and wild animals, there is a risk of a zoonotic disease spillover.
As such, the report argues that in certain cases, human challenge models should be seen as a priority to help prevent a future pandemic. However, several ethical concerns regarding deliberate infections need to be answered.
The report suggests a framework to answer two key ethical questions: is the proposed study in the public interest and does the study satisfy other ethical requirements, such as comprehensive compensation system and informed consent process.
The blueprint will offer a shorter time frame to evaluate CHIMs without posing a risk to the population. Also, if this framework is adopted, it would allow the UK government to achieve its pledge to deliver countermeasures for future pandemics within 100 days.
The demand for CHIM studies resurfaced during the Covid-19 pandemic as ethicists and epidemiologists called for the conduct of human challenge trials using SARS-CoV-2. These trials began in the UK more than a year later after the WHO declared the pandemic, which highlights the need to clarify the ethical conduct of such trials, the report notes.
However, the Covid-19 CHIM studies were done right on time, according to Peter Openshaw, professor of experimental medicine at Imperial College London. “We got it about right in terms of being cautious and not jumping in before we’d actually reviewed all the evidence,” he told Clinical Trials Arena, adding that some researchers were cautious while others were pushing for even faster study delivery.
Openshaw said that the report is a useful contribution to set out discussions about the ethical principles of Covid-19 CHIM studies and also other possible future agents. He highlighted the importance of having open and public debates on the ethics of CHIMs, involving the participants, regulators and investigators as widely as possible.