World-renowned South African HIV/Aids researcher Professor Quarraisha Abdool Karim has made history as the first woman president of the World Academy of Sciences. Professor Abdool Karim succeeded Sudanese mathematician Professor Mohamed Hassan, who will sit on the 2023–2026 council as immediate past president alongside scientists from all regions of the world. Abdool Karim is a Professor in Clinical Epidemiology at Columbia University, USA, and pro-Vice Chancellor for African Health at the University of KwaZulu-Natal, South Africa. Her scientific excellence has been recognized through more than 30 honours and awards, including the 2014 TWAS-Lenovo Prize; the Order of Mapungubwe from the President of South Africa. Her new role will for the first time see the council include a Vice-President and council member from the Global North. In this conversation, we talk about her new role at the World Academy of Sciences, look at structural and biological risk factors that facilitate the spread of HIV in young people in South Africa and discuss the social and economic factors that contribute to the dramatic differences in HIV rates in women and men at different ages.