1. Quarraisha Abdool Karim (top) and Salim S. Abdool Karim (bottom) are professors at the Mailman School of Public Health at Columbia University, New York, NY, USA, and are the associate scientific director and director, respectively, of the Centre for the AIDS Programme of Research in South Africa (CAPRISA) at the University of KwaZulu-Natal, Durban, South Africa.