Only half of volunteers deliberately exposed to SARS-CoV-2 developed an infection. None developed serious symptoms, paving the way for further challenge trials.

Since the early months of the COVID-19 pandemic, some researchers and organizations have been mulling the possibility of organizing human challenge trials on the disease, meaning that people would be deliberately infected under controlled conditions in order to better study its course. The first such trial, using the original strain of SARS-CoV-2, got underway in April 2021. On February 1, the authors posted their results as a preprint. They report no safety issues in their study cohort of 36 young adults and some preliminary data on the trajectory of a bout of COVID-19.

“This study has already generated intriguing insights into the timeline of infection, particularly in the early phase,” Doug Brown, the chief executive of the British Society for Immunology who was not involved in the study, says in comments to the Science Media Centre. “In the longer-term, the hope is that these findings will now open up a new research avenue to develop a platform that will allow us to speed up the development of new vaccines, antivirals and diagnostics against COVID-19.”

Read more...