Funding for this research was provided by:
Bill & Melinda Gates Foundation (OPP1032350)
Received: 18 March 2019
Accepted: 22 July 2019
First Online: 30 July 2019
Ethics approval and consent to participate
: Ethical approval for initial data collection and secondary analysis was obtained in Zambia from the Research Ethics Committee (REC) at the University of Zambia. Ethical approval was also obtained from the Tulane Institutional Review Board and PATH.
: Not applicable.
: The authors declare that they have no competing interests.