Funding for this research was provided by:
WHO Regional Office for the Western Pacific (00000)
Received: 6 October 2019
Accepted: 11 February 2020
First Online: 12 March 2020
Ethics approval and consent to participate
: Ethics approval was waived for this work by the Western Pacific Regional Office Ethics Research Council (WPRO-ERC).
: Not applicable.
: The authors declare they have no competing interests.