[1] St Jude Childrens Res Hosp, Dept Infect Dis, Memphis, TN 38105 USA
[2] Univ Tennessee, Hlth Sci Ctr, Dept Pediat, Memphis, TN USA
[3] Univ Tennessee, Hlth Sci Ctr, Dept Prevent Med, Memphis, TN USA
[4] Duke Univ, Dept Pediat, Sch Med, Durham, NC 27706 USA
[5] NYU, Dept Pediat, Sch Med, New York, NY 10016 USA
[6] Univ Alabama Birmingham, Dept Epidemiol, Birmingham, AL USA
[7] Eunice Kennedy Shriver Natl Inst Child Hlth & Hum, Pediat Adolescent & Maternal AIDS Branch, NIH, Rockville, MD USA
[8] Westat Corp, Rockville, MD USA
[9] Core Ctr, Adolescent Div, Chicago, IL USA