The world’s first medical trial requires additional volunteers as scientists step up efforts to develop better vaccines. The study at Oxford University began in April last year.
The first phase, which is still ongoing, aims to figure out how much “amount” of virus (viral load) is needed to cause an infection, while the second focuses on determining the immune response needed to prevent infection.
Researchers are close to identifying the degree of viral load that would guarantee that about half of people will develop COVID-19 asymptomatically or mildly.
They then plan to expose volunteers to this dose of the original version of the virus to determine what levels of antibodies or T cells are needed to prevent infection.
“We have learned a lot about Covid-19 over the past two years, but the advent of new variants means we may need to keep improving vaccines,” said Ellen McShane, professor at the University of Oxford and lead researcher.
The test results will help make future vaccine development much more efficient and effective.
Volunteers for the second stage of testing
Now that the researchers are close to completing the first phase of the project, volunteers are being sought for the second phase.
The study involved individuals between the ages of 18 and 30 in “excellent health”. After exposure to the virus, they will be quarantined for at least 17 days, and anyone with symptoms will be treated with monoclonal antibodies.