1. Department of Preventive Medicine & Public Health, University of Kansas School of Medicine, 3901 Rainbow Boulevard, MS 1008, Kansas City, KS 66160, USA
2. City of Kansas City, Missouri, Health Department, 2400 Troost Avenue, Suite 3300, Kansas City, MO 64108, USA
3. Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San Francisco, CA, USA
4. Epidemiology, Research, & Surveillance, STD Prevention & Control Services, San Francisco Department of Public Health, San Francisco, CA, USA
5. Sexually Transmitted Disease Program, Division of HIV/STD Programs, Los Angeles County Department of Public Health, Los Angeles, CA, USA
6. Cardea Services, Seattle, WA, USA
7. Division of Epidemiology, University of California at Berkeley, CA, USA