New: Interesting report on a human challenge study in the UK that exposed healthy young volunteers to the SARS-CoV-2 virus.
First human challenge study of Covid-19 yields valuable insights about how we get sick - CNN
...The study began in March 2021. The 36 volunteers were between the ages of 18 and 30. They were allowed to participate only if they didn’t have any risk factors for severe Covid-19, such as being overweight, having reduced kidney or liver function, or having any heart, lung or blood problems. They also signed an extensive informed consent form to participate....
...The volunteers got a tiny drop of fluid containing the originally detected strain of the virus through a long, thin tube inserted into their nose.
They were medically monitored 24 hours a day and stayed for two weeks in rooms at London’s Royal Free Hospital that had special air flow to keep the virus from escaping.
Half were infected
A total of 18 participants became infected, two of whom never developed symptoms. Among the people who got sick, their illnesses were mild. They had stuffy noses, congestion, sneezing and sore throats....
...This challenge study was so successful that Chiu plans to do it again, this time with vaccinated people infected with the Delta variant to study their immune response.
He says his team also plans to continue studying the people who didn’t get sick.
“That’s what’s really interesting,” he said. About half of the study participants never got sick and never developed antibodies, despite getting exactly the same dose of the virus.
Everyone was screened for antibodies to closely related viruses, like the original SARS virus. So it wasn’t cross-protection that kept them safe; it was something else....
Safety, tolerability and viral kinetics during SARS-CoV-2 human challenge in young adults | Nature Medicine
