[1] Univ Chile, Hosp Clin, Santos Dumont 999, Santiago, Chile
[2] Minist Salud, Dept Inmunizac, Monjitas 565,p7, Santiago, Chile
[3] Pontificia Univ Catolica Chile, Fac Med, Dept Salud Publ, Diagonal Paraguay 362, Santiago, Chile
[4] Minist Salud, Dept Epidemiol, Enrique Mac Iver 541, Santiago, Chile
[5] Univ Austral Chile, Fac Med, Inst Med, Coronel Santiago Bueras 1003, Valdivia, Chile
[6] Univ Chile, Fac Med, Av Independencia 1027, Santiago, Chile
[7] Clin Univ Los Andes, Av Plaza 2501, Santiago, Chile
[8] Univ La Frontera, Fac Med, Ave Francisco Salazar 01145, Temuco, Chile
[9] Clin Alemana, Unidad Infectol Pediat, Av Vitacura 5951, Santiago, Chile
[10] Inst Salud Publ Chile, Farmacovigilancia Vacunas, Av Marathon 1000, Santiago, Chile
[11] SEREMI Salud Reg Valparaiso, Melgarejo 669,Piso 6, Valparaiso, Chile
[12] WHO, Dept Family Hlth Promot & Life Course PAHO, 525 23rd St NW, Washington, DC 20037 USA