When UK authorities granted permission in October 2020 for the first controlled infection study to be carried out to test the anti-Covid-19 vaccine Oxford University had just developed, reactions ranged from disbelief to disapproval.
Yet this type of experiment, which exposes healthy volunteers to an infection to assess the efficacy of a vaccine or treatment (it is sometimes called a ‘human infection challenge’), is not just a widespread practice but also an irreplaceable one in clinical research.
But involving healthy people in biomedical research is not risk-free, as recent tragedies have shown. In what context are these healthy volunteers enlisted? What motivates them? And how are they protected?
