[1] Johns Hopkins Bloomberg Sch Publ Hlth, Baltimore, MD USA
[2] NICHD, NIH, Rockville, MD USA
[3] WHO, Child & Adolescent Hlth Dept, CH-1211 Geneva, Switzerland
[4] Cairo Univ, Cairo, Egypt
[5] Univ Infect Dis Hosp, Zagreb, Croatia
[6] Univ Fed Rio de Janeiro, Rio De Janeiro, Brazil