U.S. Government; Mexican Emerging Infectious Diseases Clinical Research Network; National Institute of Allergy and Infectious Diseases, NIAID; Ministry of Health Mexico; The Mexican Emerging Infectious Diseases Clinical Research Network; Universidad Autónoma de San Luis Potosí, UASLP; Instituto Nacional de Enfermedades Respiratorias, (C12-10); Hospital Infantil de México Federico Gómez, HIMFG, (HIM/2010/074); Hospital Infantil de México Federico Gómez, HIMFG; Instituto Nacional de Pediatria, INP, (INP 014/2010); Instituto Nacional de Pediatria, INP; Consejo Nacional de Humanidades, Ciencias y Tecnologías, Conahcyt, (127088, 71260); Consejo Nacional de Humanidades, Ciencias y Tecnologías, Conahcyt; Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, (116); World Medical Association, (NCT02378090); National Institutes of Health, NIH, (HHSN2722009000031, HHSN27200002); National Institutes of Health, NIH; National Cancer Institute, NCI, (75N91020F00004, 75N91019D00024, 75N91019F00130); National Cancer Institute, NCI Grant