2 Bill & Melinda Gates Foundation, Seattle, WA, USA.
3 Medical Research Council Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa.
4 ISGlobal, Barcelona Centre for International Health Research, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain; Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.
5 Division of Epidemiology, University of Toronto, ON, Canada.
6 University of Colorado Denver and Center for Global Health, Colorado School of Public Health, Aurora, CO, USA.
7 Fundación INFANT, Buenos Aires, Argentina; Department of Pediatrics, Vanderbilt University, Nashville, TN, USA. Electronic address: fernando.p.polack@vanderbilt.edu.