1. Department of Global Health and Population, Harvard T. H. Chan School of Public Health , Boston, Massachusetts , USA
2. Department of Health Policy and Management, Yale School of Public Health , New Haven, Connecticut , USA
3. Department of Health Policy and Management, Graduate School of Public Health, University of Pittsburgh , Pittsburgh, Pennsylvania , USA
4. Massachusetts Department of Public Health, Sexually Transmitted Disease Prevention and HIV/AIDS Surveillance , Boston, Massachusetts , USA
5. Division of STD Prevention, Centers for Disease Control and Prevention , Atlanta, Georgia , USA
6. Center for Health Policy/Center for Primary Care and Outcomes Research, Stanford University , Stanford, California , USA