First COVID-19 Human Challenge Trial Reveals Uneven Susceptibility

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

Written byShawna Williams
| 2 min read
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Update (April 1): This study was published yesterday in Nature Medicine.

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, ...

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Meet the Author

  • Shawna was an editor at The Scientist from 2017 through 2022. She holds a bachelor’s degree in biochemistry from Colorado College and a graduate certificate in science communication from the University of California, Santa Cruz. Previously, she worked as a freelance editor and writer, and in the communications offices of several academic research institutions. As news director, Shawna assigned and edited news, opinion, and in-depth feature articles for the website on all aspects of the life sciences. She is based in central Washington State, and is a member of the Northwest Science Writers Association and the National Association of Science Writers.

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