Oxford to launch human problem trial to check immune response

Caroline Nicolls will receive an injection of the Moderna Covid-19 vaccine administered by Nurse Amy Nash at Madejski Stadium in Reading, west of London, on April 13, 2021.

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LONDON – Oxford University researchers announced the start of a Human Challenge study on Monday to better understand what happens when people who have already contracted the coronavirus become infected for the second time.

The researchers will investigate what kind of immune response can prevent people from becoming infected with Covid-19 again and examine how the immune system reacts to the virus a second time.

Little is currently known about what happens to people who had the virus the second time they were infected.

The experiment is carried out in two phases with different participants in each phase. The first phase is slated to begin this month and the second phase is slated to begin in summer.

In medical research, Human Challenge studies are controlled studies in which participants are intentionally exposed to a pathogen or beetle to study the effects.

“Challenge studies tell us things that other studies cannot because, unlike natural infections, they are tightly controlled,” said Helen McShane, chief investigator for the study and professor of vaccinology in the Department of Pediatrics at Oxford University.

“If we re-infect these participants, we will know exactly how their immune systems responded to the first COVID infection, when exactly the second infection occurs, and how much virus they have,” said McShane.

It is hoped that the study will help improve scientists’ basic understanding of the virus and develop tests that can reliably predict whether people will be protected.

What happens in each phase?

In the first phase, up to 64 volunteers between the ages of 18 and 30 who were previously infected naturally will be re-exposed to the virus under controlled conditions.

Researchers will oversee attendees’ care while they perform CT scans of the lungs and MRI scans of the heart while isolating in a specially designed suite for at least 17 days.

All participants must be fit, healthy and have fully recovered from their initial infection with Covid to minimize the risk.

Study participants will only be released from the quarantine unit if they are no longer infected and there is a risk of the disease spreading.

A view of the City of London on a clear day.

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In the second phase of the experiment, two different areas are examined.

“First we will very carefully define the basic immune response of the volunteers 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.” to be able to understand what kind of immune responses protect against re-infection, “said McShane.

“Second, we will measure the immune response several times after infection so we can understand what immune response is being generated by the virus,” she added.

The entire study period is 12 months, including at least eight follow-up appointments after discharge.

“This study has the potential to change our understanding by providing high-quality data on how our immune systems react to a second infection with this virus,” said Shobana Balasingam, senior research advisor on vaccines at Wellcome, a nonprofit that funded the study.

“The results could have important implications for the future management of COVID-19, influencing not only vaccine development but research into the range of effective treatments that are also badly needed,” Balasingam said.

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