1. Division of Infectious Diseases: Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, USA
2. Center for Interdisciplinary Studies in Sexuality, AIDS and Society, Universidad Peruana Cayetano Heredia, Lima, Peru
3. Laboratory of Sexual Health, Universidad Peruana Cayetano Heredia, Lima, Peru
4. Department of Epidemiology, Fielding School of Public Health, University of California Los Angeles, USA