1. Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
2. Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
3. Department of Medicine, Emory University, Atlanta, Georgia, USA
4. San Francisco Department of Public Health, San Francisco, California, USA
5. St. Louis County Sexual Health Clinic, St. Louis, Missouri, USA
6. Division of Infectious Diseases, Washington University, St. Louis, Missouri, USA
7. Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, Georgia, USA