The risk to young, healthy participants, the argument goes, is
small to start with and offset by the potentially massive benefit to
society
It began as a proposal on the fringes of science: deliberately exposing people to COVID-19 to speed up development of vaccines, even though there’s no sure-fire treatment for the potentially lethal bug.
But the controversial idea of so-called challenge trials to test coronavirus shots seems to be picking up steam, with one huge endorsement pushing the concept ahead in recent days.
