1 Department of Global Pediatric Medicine, St Jude Children's Research Hospital, Memphis, TN, USA. Electronic address: jane.hankins@stjude.org.
2 Instituto de Hematologia Arthur Siqueira Cavalcanti, HEMORIO, Rio de Janeiro, Brazil.
3 Universidade Federal de São Paulo, São Paulo, Brazil.
4 Department of Global Pediatric Medicine, St Jude Children's Research Hospital, Memphis, TN, USA.
5 Department of Global Pediatric Medicine, St Jude Children's Research Hospital, Memphis, TN, USA; School of Public Health, University of Memphis, Memphis, TN, USA.
6 Division of Public Health Sciences, Department of Surgery, Washington University in St Louis, St Louis, MO, USA.