Received: 9 May 2019
Accepted: 27 January 2020
First Online: 22 February 2020
Ethics approval and consent to participate
: The data was coded and any identifiers of the participant were removed from the data set and it was available for public use. So this study didn’t need local ethical approval but the LSHTM ethics committee had approved the study. The national statistics office granted us the data set after officially requested.
: Not applicable
: The authors declare that they have no competing interests.