Caroline Nicolls receives an injection of the Moderna Covid-19 vaccine administered by nurse Amy Nash on 13 April 2021, at Madejski Stadium in Reading, west London.
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LONDON – Oxford University researchers on Monday announced the launch of a human challenge test to better understand what happens when people who have already contracted the coronavirus are infected for a second time.
Researchers will investigate the type of immune response that can prevent humans from being re-infected with Covid-19 and how the immune system responds to the virus a second time.
At present, little is known about what happens to people who have already had the virus when they were infected for a second time.
The trial will take place in two phases, with different participants in each phase. The first phase is expected to begin this month and the second phase will begin in the summer.
In medical research, human challenge trials are controlled studies in which participants are deliberately exposed to a pathogen or a bug to study its effects.
“Challenge studies tell us things that other studies cannot do because they, unlike natural infection, are strictly controlled,” said Helen McShane, lead researcher on the study and professor of vaccination at the Department of Pediatrics, University of Oxford.
“When we re-infect these participants, we will know exactly how their immune system reacted to the first COVID infection, exactly when the second infection occurred, and exactly how much virus they got,” McShane said.
It is hoped that the study will help to improve scientists’ basic understanding of the virus and to design tests that can reliably predict whether humans are protected.
What happens in each phase?
For phase one, up to 64 volunteers between the ages of 18 and 30 who were previously naturally infected will again be exposed to the virus under controlled conditions.
Researchers will monitor the care of the participants while undergoing CT scans of the lungs and MRI scans of the heart while isolating them for a minimum of 17 days in a specially designed suite.
All those participating must be fit and healthy and must have fully recovered from their first infection of Covid to limit the risk.
Participants in the trial will only be discharged from the quarantine unit if they are no longer infected and are at risk of spreading the disease.
A view of the City of London on a clear day.
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The second phase of the trial will explore two different areas.
“First, we will define the immune response in volunteers very carefully before we infect them. We will then infect them with the dose of virus selected 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 are protected against reinfection, ”McShane said.
“Second, we will measure the immune response at various time points after infection so that we can understand what immune response is generated by the virus,” she added.
The full duration of the study will be 12 months, including a minimum of eight follow-up appointments after discharge.
“This study has the potential to transform our understanding by providing high quality data on how our immune system responds to a second infection with this virus,” said Shobana Balasingam, senior research consultant at Wellcome, a charity that funds the study. vaccinated.
“The findings could have important implications for the management of COVID-19 in the future, and not only inform the development of vaccines, but also research on the range of effective treatments that are also urgently needed,” Balasingam said.