Volunteers have been exposed to the coronavirus that causes covid-19 as part of a scientific study
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Deliberately exposing people to the coronavirus behind covid-19 in a so-called challenge study has helped us understand why some people seem to be immune to catching the infection.
As part of the first such covid-19 study, carried out in 2021, a group of international researchers looked at 16 people with no known health conditions who had neither tested positive for the SARS-CoV-2 virus nor been vaccinated against it.
The…
