Funding for this research was provided by:
Deutscher Akademischer Austauschdienst (57445019)
Bundesministerium für Bildung und Forschung (BMBF01DP17047)
Received: 19 October 2020
Revised: 18 December 2020
Accepted: 18 December 2020
First Online: 31 December 2020
Ethics approval and consent to participate
: Informed written consent was obtained from all study participants. The study was approved by the Institutional Review Board of Vietnam Military Medical University, Hanoi, Vietnam.
: All authors have read and approved this submission. All authors have consented to publish this as an original article.
: All authors disclose no competing interests.