Human infection challenge studies are often used to test vaccines. In a traditional study, the new vaccine needs to be tested on a large number of people because not all of those enrolled will get exposed to the virus. A challenge trial makes it quicker to check on a much smaller number of people whether a vaccine protects, because in carefully controlled conditions people are deliberately infected with a virus.
A human infection vaccine challenge study for COVID-19 has several stages. The first is to screen volunteers to select people who meet the specific criteria set out in the study protocol. These volunteers will then choose whether to proceed to one of the next stages. The second is to work out the lowest possible dose of virus that would prove that the vaccine works, by deliberately giving some of the volunteers measured amounts of virus and checking for detectable signs of infection. The first two stages now have ethics approval from the specialist REC and participants are expected to join the study in the next month.
The third stage may then test one or more possible vaccines by giving a separate set of participants a novel vaccine followed by a dose of virus, and then testing for infection. This stage would need Clinical Trials Authorisation from the Medicines and Healthcare products Regulatory Agency (MHRA) as well as favourable ethics opinion.
Challenge studies require careful consideration, but the REC was uniquely qualified to do this, and its approach was praised by the study’s Chief Investigator, Chris Chiu from Imperial College London.
Chris Chiu, study Chief Investigator
The Research Ethics Committee has provided detailed independent scrutiny. Their favourable opinion is a crucial step towards getting this study open and running, and greatly helps us in our efforts to minimise risks and enhance the quality of the research.
Stephanie Ellis, Chair, explains more:
Stephanie Ellis, Specialist REC Chair
Members were chosen to ensure that we had a range of expertise and background (including ensuring a suitable geographic spread) to feel confident that we were able to give the research a rigorous but fair review.
We had two training days, several weeks apart, so that members could discuss the sorts of questions that would need to be asked about the research. We chose to adopt (but agreed not to be bound by) the WHO guidelines for reviewing challenge research: this gave us a template for our discussions.
The value of this approach was soon apparent as we began our review of the research application. The researchers had clearly worked hard to organise their research but had, understandably, not always been able to think through, for example, what participants would need to know. The depth of the discussions can be seen by the fact that our first couple of meetings lasted over three hours each: there were few moments of silence! I have to admit I was exhausted after each one.
I was lucky in having a brilliant, helpful group of members working with me. Some of them may have felt frustrated with my approach, which was very thorough, but I am confident that we were all able to contribute and that we reached good decisions that led to the research being improved, and to the participants being well informed and looked after. It has been a huge privilege to be involved in such important work.
More than one in three adults in the UK have now received at least one dose of an approved COVID-19 vaccine, but additional research, like the study approved last week, is still needed.
Interim Chair of the Vaccine Taskforce Clive Dix
No one vaccine is likely to be suited to everyone so we must continue to develop new vaccines and treatments for COVID-19 coronavirus. This will help us to ensure that people across the UK and the world can be protected against this disease. We expect these studies to offer unique insights into how the virus works and help us understand which promising vaccines offer the best chance of preventing the infection.
Professor Sir Terence Stephenson, Chair of the HRA, also praised the work of the committee:
Professor Sir Terence Stephenson, HRA Chair
The HRA has reviewed and approved almost 800 COVID-19 studies since the start of the pandemic, and we’re delighted with the feedback from the team behind this world-first human challenge study. Our REC members work tirelessly to protect research participants and ensure that high-quality studies are robustly reviewed and can begin as quickly as possible, and this study is an excellent example of their crucial role.
Information about the world’s first COVID-19 human infection challenge study, and all of the coronavirus research reviewed and approved by the HRA, can be found on the research summaries section of our website.