Caroline Nicolls will receive an injection of the Moderna Covid-19 vaccine given by nurse Amy Nash on April 13, 2021, at Madejski Stadium in Reading, west of London.
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LONDON – Researchers from the University of Oxford announced on Monday the launch of a human challenge trial to better understand what happens when people who have already contracted the coronavirus are infected a second time.
Researchers will investigate what kind of immune response could prevent people from getting reinfected with Covid-19 and examine how the immune system responds to the virus a second time.
At this point, little is known about what happens to people who have already had the virus when they are infected for the second time.
The trial takes place in two phases, with different participants in each phase. The first phase will start this month and the second phase will start in the summer.
In medical research, human challenge studies are controlled studies in which participants are intentionally exposed to a pathogen or bug to study the effects.
“Challenge studies tell us things that other studies cannot because, unlike natural infection, they are tightly controlled,” said Helen McShane, lead investigator on the study and professor of vaccinology in the Department of Pediatrics at Oxford University.
“When we re-infect these participants, we will know exactly how their immune systems responded to the first COVID infection, exactly when the second infection occurs, and exactly how much virus they got,” McShane said.
It is hoped that the study will help improve scientists’ basic understanding of the virus and design tests that can reliably predict whether humans are protected.
What happens at each stage?
For phase one, up to 64 volunteers between 18 and 30 years old who have previously been naturally infected will be re-exposed to the virus under controlled conditions.
Researchers monitor the participants’ care as they undergo CT scans of the lungs and MRI scans of the heart while isolating for a minimum of 17 days in a specially designed suite.
All participants must be fit, healthy and fully recovered from their initial Covid infection to minimize risk.
The trial participants are only released from the quarantine unit when 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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In the second phase of the trial, two different areas will be investigated.
“First, we will very accurately determine the baseline immune response in the volunteers before infecting them. We will then infect them with the dose of virus chosen from the first study and measure how much virus we can detect after infection. understand what kind of immune responses protect against reinfection, ”said McShane.
“Second, we will measure the immune response at different times after infection so that we can understand which immune response is generated by the virus,” she added.
The full duration of the trial is 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 systems respond to a second infection with this virus,” said Shobana Balasingam, senior research advisor on vaccines at Wellcome, a charity that funds the study.
“The findings could have important implications for how we treat COVID-19 in the future, providing not only vaccine development but also research into the range of effective treatments that are also urgently needed,” said Balasingam.