Exploring concurrent sexual partnerships: new definitions and estimates from a study of youth in urban Kenya • Hongwei Xu, Brown University ; Nancy Luke, Brown University ; Eliya M. Zulu, African Population and Health Research Center (APHRC)

Sexual behaviour patterns in South Africa and their effect on the spread of HIV: insights from a mathematical model • Leigh Johnson, University of Cape Town ; Debbie Bradshaw, Medical Research Council of South Africa ; Victoria Pillay-Van Wyk, Social Aspects of HIV/AIDS and Health, Human Sciences Research Council ; Thomas Rehle, Social Aspects of HIV/AIDS and Health, Human Sciences Research Council

Concurrency and HIV spread in sub-Saharan countries: biases from self-reported data and their implications for HIV prevention • Stephane Helleringer, Columbia University ; Linda Kalilani-Phiri, University of Malawi ; Jemima A. Frimpong, University of Pennsylvania

HIV/STI risk perceptions and protective actions among adults with concurrent sexual partnerships: a study of Mexican sexual biographies • Cecilia Gayet, Facultad Latinoamericana de Ciencias Sociales (FLACSO) ; Nancy Pedraza, El Colegio de México ; Marta Caballero, Instituto Nacional de Salud Pública (INSP) ; Carlos Magis Rodríguez, Centro Nacional para la Prevención y el Control del VIH/SIDA ; Michel Bozon, Institut National d'Études Démographiques (INED)