As most people obsess with avoiding COVID-19 at all costs, a rapidly growing group of people around the world says they are prepared to deliberately take on the virus.
Tens of thousands of people have signed up to a campaign by a group called 1 Day Sooner to take an experimental vaccine candidate and then face coronavirus in a controlled setting.
Among them is Estefania Hidalgo, 32, a photography student in Bristol, England.
Volunteers in challenge trials are typically compensated for their time and participation, experts say, but organizers must be careful not to pay an amount that could edge on coercive.
As of last month, however, the UK government said that it is in active conversations to collaborate on such a trial, which would be the first in the world for coronavirus.