Funding for this research was provided by:
Bill and Melinda Gates Foundation (OOP1148464)
Received: 27 December 2019
Accepted: 19 November 2020
First Online: 2 December 2020
Ethics approval and consent to participate
: This study was conducted according to the guidelines laid down in the Declaration of Helsinki, and all procedures involving research study participants were approved by the Ethics Committee of Duke University (Ref number: 2017-1359). Verbal informed consent was obtained from all subjects. Verbal consent was witnessed and formally recorded.
: All authors reviewed this manuscript and provided consent for publication.
: The authors declare that they have no competing interests.