[1] Univ Minnesota, Sch Publ Hlth, Div Epidemiol, Minneapolis, MN 55454 USA
[2] Columbia Univ Coll Phys & Surg, Dept Pediat, Div Infect Dis, New York, NY 10032 USA
[3] Harvard Univ, Sch Med, Beth Israel Deaconess Med Ctr, Div Infect Dis, Boston, MA USA
[4] Harvard Univ, Sch Med, Childrens Hosp, Div Infect Dis, Boston, MA USA
[5] NIH, Div Aids, Bethesda, MD 20892 USA
[6] Texas Childrens Hosp, Baylor Coll Med, Houston, TX 77030 USA
[7] SUNY, Brooklyn, NY USA
[8] NICHHD, Bethesda, MD 20892 USA
[9] Univ Illinois, Dept Pediat, Chicago, IL USA
[10] Univ Puerto Rico, San Juan, PR 00936 USA