1. Department of Health Behavior and Health Education, University of Michigan School of Public Health, Ann Arbor, MI, USA
2. Department of Health Behavior, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
3. Clinica de Familia La Romana, La Romana, Dominican Republic
4. HIV Vaccine Trials Unit, Instituto Dermatológico y Cirugía de Piel, Santo Domingo, Dominican Republic
5. Division of Infectious Diseases, University of Illinois at Chicago, Chicago, IL, USA