[1] Univ Fed Bahia, Sch Med, Dept Paediat, Salvador, BA, Brazil
[2] Univ Sao Paulo, Fac Publ Hlth, Sao Paulo, Brazil
[3] Adolfo Lutz Inst, Bacteriol Branch, Sao Paulo, Brazil
[4] Hosp Ninos Elizalde, Buenos Aires, DF, Argentina
[5] Univ Fed Minas Gerais, Sch Med, Dept Pediat, Belo Horizonte, MG, Brazil
[6] Santa Casa Sao Paulo Med Sch, Sao Paulo, Brazil
[7] Hosp Municipal Durand, Buenos Aires, DF, Argentina
[8] Martagao Gesteira Paediat Inst, Rio De Janeiro, Brazil
[9] Hosp Infantil Dr Robert Reid Cabral, Santo Domingo, Dominican Rep
[10] Inst Materno Infantil Pernambuco, Recife, PE, Brazil
[11] Pan Amer Hlth Org, Child & Adolescent Hlth Unit, Washington, DC USA