Funding for this research was provided by:
Bill and Melinda Gates Foundation
Received: 29 August 2017
Accepted: 1 August 2018
First Online: 29 August 2018
Ethics approval and consent to participate
: Ethics approval was obtained from the Institutional Review Boards of the London School of Hygiene and Tropical Medicine and the Ministry of Science and Technology in Ethiopia. Written informed consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.
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