This obituary is part of a series about people who have died in the coronavirus pandemic.

After earning a Ph.D. at the University of Natal in Durban, South Africa, in 1994 while raising two young children, Gita Ramjee was exhausted.

Her thesis had been on kidney diseases in children — she had worked in a pediatrics ward at a local hospital — but she took a job on a small research project in a different field, since it promised a less frantic pace. It was a life-changing choice.

The research involved whether a vaginal microbicide was useful against AIDS, which was rampant in South Africa. The research put her in contact with sex workers, who told chilling stories of economic hardship, high-risk behavior and men who were indifferent to using protection.

“It opened my eyes,” Dr. Ramjee told The Guardian in 2007.

“That’s when I knew I wanted to be involved in the prevention of H.I.V. infection in women,” she added.