Text and Data Mining valid from 2020-04-28
Received: 3 December 2019
Accepted: 8 April 2020
First Online: 28 April 2020
Ethics approval and consent to participate
: The study protocol was reviewed and granted ethics approval by the Institutional Review Board of National Institute of Hygiene and Epidemiology (code: 726/QDVSDTTU).
: Not applicable.
: The authors declare that they have no competing interests.