British researchers at the University of Oxford will start a new trial on Monday in which participants who have already had the coronavirus are again exposed to the lung disease.
They want to see how the immune system responds and whether they can become infected again.
In February, the country was the first in the world to authorize human trials in which volunteers were deliberately infected with Covid-19 to conduct extensive research into the disease caused by the coronavirus. With the new research, scientists mainly want to gain more knowledge about immunity.
“The information from this study will enable us to develop better vaccines and treatments. And also help us understand if people are protected after Covid, and for how long,” said Helen McShane, an Oxford vaccinologist and lead investigator of the study research. She also hopes to gain more insight into which immune responses protect against reinfection.
Scientists have been using human subjects for decades to learn about diseases such as malaria, flu, typhoid and cholera, and to develop treatments and vaccines against these diseases.
The first phase of the trial looks at the lowest dose of the virus needed to multiply in about half of the participants, with little or no symptoms. In the second phase, starting this summer, several volunteers will be infected with this standard dose.
In phase one, up to 64 healthy participants aged 18 to 30 who were infected with the coronavirus at least three months ago will be reinfected with the original strain of SARS-CoV-2.
They are then quarantined and monitored for at least 17 days. Anyone who develops symptoms will receive Regeneron treatment. That is the means that the American ex-president Donald Trump received after his corona infection. Regeneron combines two antibodies that together fight the coronavirus in the body, called casirivimab and imdevimab.