Overall support for the International Maternal Pediatric Adolescent AIDS Clinical Trials Group (IMPAACT) was provided by the National Institute of Allergy and Infectious Diseases (NIAID) [U01 AI068632], the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), and the National Institute of Mental Health (NIMH) [AI068632]. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. This work was supported by the Statistical and Data Analysis Center at Harvard School of Public Health, under the NIAID cooperative agreement #5 U01 AI41110 with the Pediatric AIDS Clinical Trials Group (PACTG) and #1 U01 AI068616 with the IMPAACT Group. Support of the sites was provided by the NIAID (NIAID) the NICHD International and Domestic Pediatric and Maternal HIV Clinical Trials Network funded by NICHD (contract number N01-DK-9-001/HHSN267200800001C). The following institutions and individuals participated in PACTG Protocols 219 and/or 219C: Baylor Texas Children’s Hospital: F Minglana, ME Paul, CD Jackson; University of Florida, Jacksonville: MH Rathore, A Khayat, K Champion, S Cusic; Chicago Children’s Memorial Hospital: R. Yogev, E. Chadwick; University of Puerto Rico, University Children’s Hospital AIDS Program: I. Febo-Rodriguez, S. Nieves; Bronx Lebanon Hospital Center; M Purswani, S Baksi, E Stuard, M Dummit; San Juan Hospital: M Acevedo, M Gonzalez, L Fabregas, ME Texidor; University of Miami: GB Scott, CD Mitchell, L Taybo, S Willumsen; University of Medicine & Dentistry of New Jersey: L Bettica, J Amour, B Dashefsky, J Oleske; Charity Hospital of New Orleans & Earl K. Long Early Intervention Clinic: M Silio, T Alchediak, C Boe, M Cowie; UCSD Mother, Child & Adolescent HIV Program: SA Spector, R Viani, M Caffery, L Proctor; Howard University: S Rana, D Darbari, JC Roa, PH Yu; Jacobi Medical Center: M Donovan, R Serrano, M Burey, R Auguste; St. Christopher’s Hospital for Children, Philadelphia: J. Chen, J. Foster; Baystate Medical Center Children’s Hospital: BW Stechenberg, DJ Fisher, AM Johnston, M Toye; Los Angeles County Medical Center/USC: J Homans, M Neely, LS Spencer, A Kovacs; Children’s Hospital Boston:S Burchett, N Karthas; Children’s Hospital of Michigan: E. Moore, C. Cromer; St. Jude Children’s Research Hospital, Memphis: PM Flynn, N Patel, M Donohoe, S Jones; New York University School of Medicine/Bellevue Hospital: W Borkowsky, S Chandwani, N Deygoo, S Akleh; The Children’s Hospital at Downstate: E Handelsman, HJ Moallem DM Swindell, JM Kaye; The Columbia Presbyterian Medical Center & Cornell University New York Presbyterian Hospital: A Higgins, M Foca, P LaRussa, A Gershon; The Children’s Hospital of Philadelphia: RM Rutstein, CA Vincent, SD Douglas, GA Koutsoubis; Children’s Hospital of Oakland: A Petru, T Courville; UCSF, Moffitt Hospital: D Wara, D Trevithick; Children’s Hospital, University of Colorado, Denver: E. McFarland, C. Salbenblatt;Johns Hopkins University Pediatrics: N Hutton, B Griffith, M Joyner, C Kiefner; Children’s Hospital and Regional Medical Center, Washington: M Acker, R Croteau, C McLellan, K Mohan; Metropolitan Hospital Center: M. Bamji, I. Pathak, S. Manwani, E. Patel; Children’s National Medical Center: H. Spiegel, V. Amos; University of Massachusetts Medical School: K Luzuriaga; University of Alabama at Birmingham:R Pass, M Crain; University of Maryland Medical Center: J Farley, K Klipner; Schneider Children’s Hospital: VR Bonagura, SJ Schuval, C Colter, L Campbell; Boston Medical Center: SI Pelton, AM Reagan; University of Illinois: KC Rich, K Hayani, M Bicchinella; SUNY Stony Brook: S Nachman,, D Ferraro, S Madjar; North Broward Hospital District: A. Puga; Duke University: F Wiley, K Whitfield, O Johnson, R Dizney; Harlem Hospital: S Champion, M Frere, M DiGrado, EJ Abrams; Cook County Hospital: J. Martinez; University of South Alabama: M Mancao; Connecticut Children’s Medical Center: J. Salazar, G. Karas; University of North Carolina at Chapel Hill: T Belho, B Pitkin, J Eddleman; Ruiz Arnau University Hospital: W. Figueroa, E. Reyes; SUNY Upstate Medical University: LB Weiner, KA Contello, WA Holz, MJ Famiglietti; Children’s Medical Center of Dallas; University of Florida at Gainesville: R Lawrence, J Lew, C Delany, C Duff; Children’s Hospital at Albany Medical Center: AD Fernandez, PA Hughes, N Wade, ME Adams; Lincoln Medical & Mental Health Center; Phoenix Children’s Hospital: JP Piatt, J Foti, L Clarke-Steffen; Public Health Unit of Palm Beach County: J. Sleasman, C. Delaney; Medical College of Georgia: CS Mani; Yale University School of Medicine: WA Andiman, S Romano, L Hurst, J de Jesus; Vanderbilt University Medical Center: G Wilson; University of Rochester Medical Center: GA Weinberg, F Gigliotti, B Murante, S Laverty; St. Josephs Hospital and Medical Center, New Jersey: N. Hutchcon, A. Townley; Emory University Hospital: S. Nesheim, R. Dennis; University of South Florida: P Emmanuel, J Lujan-Zilberman, C Graisberry, S Moore; Children’s Hospital of the King’s Daughters: RG Fisher, KM Cunnion, TT Rubio, D Sandifer; Medical University of South Carolina: GM Johnson; University of Mississippi Medical Center: H. Gay, S. Sadler; Harbor-UCLA Medical Center: M Keller, J Hayes, A Gagajena, C Mink; Mount Sinai Medical Center: D. Johnson; Children’s Hospital of Los Angeles: J. Church, T. Dunaway, C. Salata; Long Beach Memorial: A. Deveikis, L. Melton; Robert Wood Johnson Medical School: S Gaur, P Whitley-Williams, A Malhotra, L Cerracchio; Sinai Children’s Hospital: M Dolan, J D’Agostino, R Posada; The Medical Center, Pediatric Columbus, Georgia: C. Mani, S. Cobb; Medical College of Virginia: SR Lavoie, TY Smith; Cooper Hospital - University Medical Center: A. Feingold, S. Burrows-Clark; University of Cincinnati: J. Mrus, R. Beiting; Columbus Children’s Hospital: M Brady, J Hunkler, K Koranyi; Sacred Heart Children’s CMS of Florida: W. Albritton; St. Luke’s/Roosevelt Hospital Center: R Warford, S Arpadi; Incarnation Children’s Center, New York: A. Gershon, P. Miller; Montefiore Medical – AECOM: A. Rubinstein, G. Krienik; Children’s Hospital of Los Angeles: A. Kovacs and E. Operskalski; San Francisco General Hospital: D. Wara, A. Kamrin, S. Farrales; Cornell University New York Presbyterian: R. Johan-Liang, K. O’Keefe; St. Louis Children’s Hospital: KA McGann, L Pickering, GA Storch; North Shore University Hospital: S. Pahwa, L. Rodriquez; Oregon Health and Science University: P. Lewis, R. Croteau.