[1] Childrens Hosp Philadelphia, Div Infect Dis, Philadelphia, PA 19104 USA
[2] Childrens Hosp Philadelphia, Ctr Pediat Clin Effectiveness, Philadelphia, PA 19104 USA
[3] Univ Penn, Sch Med, Dept Pediat & Epidemiol, Philadelphia, PA 19104 USA
[4] Goethe Univ Frankfurt, Frankfurt, Germany
[5] Univ Childrens Hosp Muenster, Munster, Germany
[6] Duke Univ, Dept Pediat, Div Pediat Infect Dis, Durham, NC 27706 USA
[7] Duke Univ, Dept Mol Genet & Microbiol, Div Pediat Infect Dis, Durham, NC USA
[8] Univ Texas SW Med Ctr Dallas, Dept Pediat, Div Pediat Infect Dis, Dallas, TX 75390 USA
[9] Univ Hosp Gasthuisberg, Dept Hematol, B-3000 Leuven, Belgium
[10] Merck Res Labs, Dept Clin Res, West Point, PA USA
[11] Merck Res Labs, Dept Biostat, West Point, PA USA
[12] Merck Res Labs, Dept Med Commun, West Point, PA USA