Researchers at the University of Oxford have launched a human challenge trial to look at what kind of immune response can stop people from becoming re-infected. They also want to see how the immune system reacts second time round. A human challenge trial in medical research is a carefully controlled study that involves purposefully infecting a subject with a pathogen or bug, in order to study the effects of that infection.
The study will take place in two phases with different participants in each phase. The first phase, which will start in April 2021, will establish the lowest dose of virus which, in approximately 50% of people who have previously been naturally infected, can take hold and start replicating but produce little or no symptoms. In the second phase of the study, expected to start in summer 2021, all participants will be infected with the standardised dose of virus which was established in phase one.