Tributes are being paid to world-renowned South African scientist Gita Ramjee, who died on Tuesday of Covid-19 complications.

Prof. Ramjee had recently returned home from a trip to London and was admitted with pneumonia to a hospital in Umhlanga, in KwaZulu-Natal province, the Daily Maverick news site reports.

Her research, which focused on ways to prevent HIV transmissions in women in South Africa, earned her recognition around the world.

She was chief scientific officer at the Aurum Institute and former Chief Specialist Scientist and Director of an HIV research unit at the South African Medical Research Council (SAMRC).

Glenda Gray, SAMRC's president and CEO, said: "She was tireless in this pursuit. Her tenacity will never be forgotten. I have tremendous respect for her contribution and her passion to find solutions for women in our country."

Prof. Gavin Churchyard, CEO of the Aurum Institute where she worked, said: "Her ground-breaking research in HIV prevention contributed to the global response to HIV and Aids."

And Winnie Byanyima, the executive director of UNAids, tweeted that she was deeply saddened by the news, saying Dr Ramjee's death was a "huge loss at a time when the world needs her most".