UK Launches COVID-19 Vaccine Human-Challenge Study

Researchers at the University of Oxford in England announced on April 19, 2021, they have launched a COVID-19 vaccine human challenge trial to look at what kind of immune response can stop people from becoming re-infected.

These researchers also want to see how the immune system reacts the second time around.

A human challenge trial in medical research is a carefully controlled study that involves purposefully infecting a subject with a pathogen or bug to study the effects of that infection, says the Oxford press statement.

Any participants who develop any symptoms will be given medical treatment with the Regeneron monoclonal antibody treatment. They will only be discharged from the quarantine unit when they are no longer infected and not at risk of infecting others. The full length of the study will be 12 months, including a minimum of eight follow-up appointments after discharge. Participation in the study is completely voluntary.

The virus used in the study will be the original strain from Wuhan, China.

The study participants will be quarantined in a specially designed hospital suite for a minimum of 17 days under the care of the research team. They will undergo numerous medical tests, including CT scans of the lungs and MRI scans of the heart. The risks to participants will be minimized by ensuring that those who take part are completely fit and well and have completely recovered from their first infection with COVID.

Helen McShane, Professor of Vaccinology at the Department of Paediatrics, University of Oxford and Chief Investigator on the study, said in a press release, ‘Challenge studies tell us things that other studies cannot because, unlike natural infection, they are tightly controlled."

"When we re-infect these participants, we will know exactly how their immune system has reacted to the first COVID infection, exactly when the second infection occurs, and exactly how much virus they got. As well as enhancing our basic understanding, this may help us to design tests that can accurately predict whether people are protected."

"In phase two, we will explore two different things. First, we will define the baseline immune response in the volunteers very carefully before we infect them. We will then infect them with the dose of virus chosen from the first study and measure how much virus we can detect after infection. We will then be able to understand what kind of immune responses protect against re-infection."

"Second, we will measure the immune response at several time points after infection to understand what the virus generates immune response.

"A challenge study allows us to make these measurements very precisely because we know exactly when someone is infected. The information from this work will allow us to design better vaccines and treatments and understand if people are protected after having COVID and for how long."

The Wellcome Trust funds the study. Shobana Balasingam, Vaccines Senior Research Advisor at Wellcome.