[1] Inst Nacl Pediat, Mexico City, DF, Mexico
[2] Hosp Infantil Mexico Dr Federico Gomez, Dept Infectol, Calle Dr Marquez 162, Mexico City 06720, DF, Mexico
[3] GSK, Panama City, Panama
[4] GSK, Mexico City, DF, Mexico
[5] Cerrada Merced Huertas 13, Mexico City 11340, DF, Mexico
[6] Univ Nacl Autonoma Mexico, Fac Quim, 54 Circuito Exterior S-N, Mexico City 04510 55, DF, Mexico