Adults to be re-infected to study immune response in UK Covid-19 human challenge trial

Healthy young adults who have already contracted Covid-19 will be recruited to participate in a new human challenge trial to study how the body’s immune system responds to the deadly coronavirus, for a better understanding of how to protect against the virus and also to more precise tests.

The human challenge trial led by the University of Oxford will examine what type of immune response can prevent people from reinfecting themselves and how the immune system responds a second time.

People between the ages of 18 and 30 who have previously been naturally infected will be recruited and re-exposed to the virus in a safe and controlled environment and paid around 5,000 pounds to be quarantined for 17 days in a hospital.

“Challenge studies tell us things that other studies cannot because, unlike natural infection, they are tightly controlled. When we re-infect these participants, we will know exactly how their immune system responded to the first Covid infection, exactly when the second infection occurs and how much virus they contracted, ”said Helen McShane,

Professor of Vaccinology in the Department of Pediatrics at the University of Oxford and lead researcher on the study.

The study will take place in two phases with different participants in each phase.

The first phase, which will begin this month, will establish the lowest dose of virus which, in about 50% of people who have been naturally infected before, can settle in and start to replicate but produce little or no symptoms.

In the second phase of the study, which is expected to start later this year, all participants will be infected with the standardized dose of the virus that was established in the first phase. Prof McShane said his team would start by very carefully defining the baseline immune response in volunteers, before infecting them.

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They will then infect them with the dose of virus chosen in the first study and measure how much virus we can detect after infection.

They will then be able to understand what types of immune responses protect against reinfection.

They will also measure the immune response several times after infection to understand what immune response is being generated by the virus.

“A challenge study allows us to perform these measurements very precisely because we know exactly when a person is infected. The information from this work will allow us to design better vaccines and treatments, and also understand whether people are protected after receiving Covid, and for how long, ”McShane said, adding that it would also help design tests. able to predict more precisely. if people are protected.

For the first phase, up to 64 healthy participants between the ages of 18 and 30 who have previously been naturally infected with Covid-19 will be re-exposed to the virus under carefully controlled conditions.

The virus used in the study will be the original strain from Wuhan, China.

Participants will be quarantined in a specially designed hospital suite for a minimum of 17 days under the care of the research team.

They will undergo many medical tests, including CT scans of the lungs and MRIs of the heart.

Risks to participants will be minimized by ensuring that those who participate are perfectly fit and healthy and have fully recovered from their first infection with Covid, the researchers said.

All participants, recruited on a voluntary basis, who develop symptoms will receive medical treatment with Regeneron monoclonal antibody therapy.

They will only be released from the Quarantine Unit when they are no longer infected and are not at risk of infecting others. The total duration of the study will be 12 months, including a minimum of eight follow-up appointments after discharge.

The research team explained that a human challenge trial in medical research is a carefully controlled study that involves deliberately infecting a subject with a pathogen or insect, in order to study the effects of that infection. .

“There are still many unknowns surrounding this virus and studies of human infections can tell us a lot about Covid-19. 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 Vaccine Research Advisor at Wellcome Trust, trial funders.

“The findings could have important implications for how we treat Covid-19 in the future and inform not only vaccine development, but also research into the range of effective treatments that are also urgently needed. Keeping up with the pace of scientific research and development, through crucial studies like this, remains the only way to really get ahead of this pandemic and get it under control, ”she said.