[1] Columbia Univ, Heilbrunn Dept Populat & Family Hlth, Mailman Sch Publ Hlth, New York, NY 10032 USA
[2] Columbia Univ, Dept Biostat, Mailman Sch Publ Hlth, New York, NY 10032 USA
[3] Columbia Univ, Dept Epidemiol, Mailman Sch Publ Hlth, New York, NY 10032 USA
[4] Uganda Virus Res Inst, Rakai Hlth Sci Program, Entebbe, Uganda
[5] Johns Hopkins Univ, Dept Epidemiol, Bloomberg Sch Publ Hlth, Baltimore, MD USA
[6] Makerere Univ, Sch Publ Hlth, Kampala, Uganda