Researchers at the University of Oxford have launched a trial to look at what kind of immune response can stop people becoming re-infected with Covid-19.
The risks to participants will be minimised by making sure that those who take part are completely fit and well and have completely recovered. They'll also have to quarantine while taking part.
The findings could have important implications for how we handle Covid-19 in the future and develop vaccines.
The study, which is funded by the Wellcome Trust and is expected to start this month after receiving ethics approval, will recruit people aged 18-30 who have previously been naturally infected with Covid-19.
Volunteers will be re-exposed to the virus in a safe and controlled environment while a team of researchers monitor their health.
Human challenge studies have played a key role in furthering the development of treatments for diseases such as malaria, TB, typhoid, cholera and flu.
A similar study is ongoing in the UK where volunteers are being infected with coronavirus to test vaccines and treatments.
Helen McShane, professor of vaccinology at the department of paediatrics, University of Oxford and chief investigator on the study, said: “Challenge studies tell us things that other studies cannot because, unlike natural infection, they are tightly controlled."
While Covid-19 infections have been rare, recent research suggests prior infection may not fully protect young people against reinfection.
The observational study, published in the Lancet involving US Marine Corps members mostly aged 18-20, showed that between May and November 2020, around 10% of participants who had previously caught coronavirus became re-infected.
The Oxford study will take phase in two phases.The first phase, involving 64 healthy volunteers, will aim to establish the lowest dose of virus which can take hold and start replicating.
Once the dosing amount is established, it will be used to infect participants in the second phase of the study, which is expected to start in the summer.