[1] Childrens Hosp Philadelphia, Div Infect Dis, Philadelphia, PA 19104 USA
[2] Childrens Hosp Philadelphia, Div Gen Pediat, Philadelphia, PA 19104 USA
[3] Childrens Hosp Philadelphia, Div Emergency Med, Philadelphia, PA 19104 USA
[4] Childrens Hosp Philadelphia, Clin Virol Lab, Philadelphia, PA 19104 USA
[5] Univ Penn, Sch Med, Ctr Clin Epidemiol & Biostat, Philadelphia, PA 19104 USA
[6] Univ Penn, Sch Med, Dept Pediat, Philadelphia, PA 19104 USA
[7] Univ Penn, Sch Med, Dept Biostat & Epidemiol, Philadelphia, PA 19104 USA
[8] Univ Penn, Sch Med, Dept Pathol, Philadelphia, PA 19104 USA