Thousands of people have volunteered to be infected in the hope of finding a vaccine for the new coronavirus.

hVIVO, a clinical research group in London, has attracted more than 20,000 volunteers willing to be infected with tamer relatives of the virus that causes Covid-19 in exchange for a fee of £3,500 ($4,480). It says such experiments could play an important role in the development of a vaccine against the new coronavirus, for which there are no proven treatments or vaccines.