[1] Harvard TH Chan Sch Publ Hlth, Dept Global Hlth & Populat, 90 Smith St,Room 330, Boston, MA 02120 USA
[2] Yale Sch Publ Hlth, Dept Hlth Policy & Management, New Haven, CT USA
[3] Univ Pittsburgh, Grad Sch Publ Hlth, Dept Hlth Policy & Management, Pittsburgh, PA USA
[4] Massachusetts Dept Publ Hlth, Sexually Transmitted Dis Prevent & HIV AIDS Surve, Boston, MA USA
[5] Ctr Dis Control & Prevent, Div STD Prevent, Atlanta, GA USA
[6] Stanford Univ, Ctr Hlth Policy, Ctr Primary Care & Outcomes Res, Stanford, CA 94305 USA