Received: 7 March 2018
Accepted: 10 September 2019
First Online: 4 November 2019
Ethics approval and consent to participate
: Ethical approval for the study was obtained from the Ethical Review Committee (ERC) of icddr,b. Informed written consent was obtained from all the participants. None of the participants refused to participate.
: Not applicable.
: The authors declare that they have no competing interests.