Dem don dey ask healthy young pipo wey don catch Covid-19 before to volunteer for trial wey go deliberately expose them to di pandemic virus.

Di experts behind di study, wey go begin dis month, want see how di immune system go cope di second time round.

Di ultimate aim na to design better treatments and vaccines.

Up to 64 pipo wey dey aged 18-30 go spend 17 days for quarantine unit for hospital suite and go go through plenty tests, including lung scans.

Dem go dey re-exposed to di virus, di original strain from Wuhan, China, for "safe and controlled environment" while di medical team go monitors their health.

Develop symptoms

Di first phase of dis study, wey di Wellcome Trust dey fund, aim to establish di lowest dose of virus wey fit take hold and start to replicat but produce few or no symptoms.

Dem go den use dis dose to infect participants for di second phase of di study, wey dem expect to start in di summer.

Volunteers wey develop symptoms go collect antibody treatment to help dem fight off di infection.

Dem go discharge dem only when dem no longer dey contagious.

Anti-viral therapies

Chief investigator Prof Helen McShane, from University of Oxford, tok say : "Challenge studies tell us tins wey other studies no fit because, unlike natural infection, dem dey tightly controlled.

"When we reinfect these participants, we go know exactly how their immune system don react to di first Covid infection, exactly when di second infection occur, and exactly how much virus dem get.

"As well as to enhance our basic understanding, dis fit help us to design tests wey fit accurately predict whether pipo dey protected."