The world’s first medical trial allowed to deliberately expose participants to the coronavirus is looking for more volunteers as it steps up efforts to help develop better vaccines.

The Oxford University trial was launched last April, three months after Britain became the first country to approve so-called human challenge trials involving COVID-19 .

Its first phase, still ongoing, focused on finding out how much virus is needed to trigger an infection while the second will aim to determine the immune response needed to ward off one, the university said in a statement on Tuesday. .

Researchers are on the verge of establishing the lowest possible viral infection that ensures that about half of people exposed to it get asymptomatic or mild COVID-19.

They then plan to expose volunteers – all previously naturally infected or vaccinated – to this dose of the original variant of the virus to determine what levels of antibodies or immune T cells are needed to prevent an infection.

“It’s the immune response that we then need to induce with a new vaccine,” said Helen McShane, professor of vaccinology at the University of Oxford and lead researcher on the study.

The results of the trial will help make the development of future vaccines much faster and more efficient, according to the statement.

Global immunologists have sought to identify the immune response a vaccine must produce to protect against disease, known as the correlate of protection. Once discovered, the need for mass vaccine trials is greatly reduced.

Scientists have used human challenge trials for decades to develop treatments for many infectious diseases, but this is the first known research of its kind on COVID-19.

One downside is the risk of harm to volunteers who contract the disease, but the university is taking precautions.

Participants must be in good health and between the ages of 18 and 30. They will be quarantined for at least 17 days and anyone who develops symptoms will receive the monoclonal antibody treatment of Regeneron Ronapreve.

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