A coronavirus treatment that has already been approved in the UK has helped patients recover within three days. Convalescent plasma therapy involves giving people a dose of blood donated by Covid-19 survivors, which contains the antibodies their immune system needs to fight off the virus.
The technique was first introduced a century ago during the Spanish flu pandemic, and is already being used in China, Italy and the US.
Dr Mike Ryan, head of the World Health Organisation 's health emergencies program, has labelled the potentially lifesaving treatment a "very important area to pursue".
There's still not enough evidence to say whether it's effective yet, but with more than a million infections worldwide and no vaccine in sight, it's a