Funding for this research was provided by:
Bill and Melinda Gates Foundation
John D. and Catherine T. MacArthur Foundation
Received: 7 June 2017
Accepted: 25 September 2017
First Online: 11 October 2017
Ethics approval and consent to participate
: This study was granted exemption from IRB review by the Harvard T.H. Chan School of Public Health Office of Human Research Administration.
: Not applicable.
: The authors declare that they have no competing interests.
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