New Covid trial will help in understanding immunity

scientists on Monday (19) launched a trial which will deliberately expose participants who have already had Covid-19 to the virus again to examine immune responses and see whether people get re-infected.

In February, Britain became the first country in the world to approve so-called “challenge trials” in humans, in which volunteers are deliberately exposed to Covid-19 to advance research into the disease caused by coronavirus.

This study differs from the one announced in February as it seeks to reinfect people who have previously had Covid to deepen understanding about immunity, rather than infecting people for the first time.

“The information from this work will allow us to design better vaccines and treatments, and also to understand if people are protected after having Covid, and for how long,” said Helen McShane, a University of Oxford vaccinologist and chief investigator on the study.

She added that the work would help scientists’ understanding of which immune responses protect against reinfection.

The first stage of the trial will seek to establish the lowest dose of the coronavirus needed for it to start replicating in about 50 per cent of participants, while producing few to no symptoms. A second phase, starting in the summer, will infect different volunteers with that standard dose.