Funding for this research was provided by:
Wellcome Trust (Asia Program Core Grant, Clinical Research Fellow)
Received: 8 September 2019
Accepted: 19 February 2020
First Online: 28 February 2020
Ethics approval and consent to participate
: Ethical approval and consent were not sought as all data was available open source and in aggregated form only.
: Not applicable.
: The authors declare that they have no competing interests.