Tributes are being paid to world-renowned South African scientist Gita Ramjee, who has died from Covid-19-related complications."She dedicated many years of her life to finding HIV prevention solutions for women," her colleague and friend Gavin Churchyard told the BBC.
Head of UNAids Winnie Byanyima said Prof Ramjee's death was a huge loss at a time when the world needed her most.
South Africa has the largest number of people living with HIV in the world.
The country has begun a three-week lockdown as part of efforts to stop the spread of coronavirus.