Received: 6 June 2017
Accepted: 12 February 2018
First Online: 27 February 2018
: S-AO is a WHO staff member. The contents of this paper are the responsibility of the authors and do not necessarily reflect the decisions or policies of the WHO.
: The Ministry of Health Research Division Ethical Review Board gave ethical approval for the study. The study was a secondary data analysis and did not involve contact with individual patients so consent to participate was not applicable.
: Not applicable.
: The authors declare no competing interests.