Funding for this research was provided by:
Bill and Melinda Gates Foundation
Agencia Española de Cooperación Internacional para el Desarrollo
Instituto Carlos Slim de la Salud
Received: 9 December 2016
Accepted: 2 March 2018
First Online: 20 March 2018
: Authors declare that no competing interests exist.
: The study received institutional review board approval from the University of Washington, partnering data collection agencies, and the Ministry of Health in each country. Participants were asked to sign a written consent form prior to taking part in the study.
: Not applicable.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.