1. Department of Health, Behavior and Society, Johns Hopkins School of Public Health, Baltimore, MD, USA
2. Department of Health Behavior & Health Education, University of Michigan School of Public Health, Ann Arbor, MI, USA
3. Department of Health Behavior, Gillings School of Global Public HealthUniversity of North Carolina, Chapel Hill, NC, USA
4. HIV Vaccine Trials Unit, Instituto Dermatológico y Cirugía de Piel, Santo Domingo, Dominican Republic
5. Centers for Disease Control and Prevention, Santo Domingo, Dominican Republic
6. Division of Infectious Diseases, University of Illinois at Chicago, Chicago, IL, USA