Ethics approvals and consent to participate
The study protocol has been approved by the Curtin Human Research Ethics Committee (Ref: HRE2019–0143-03) and the Ethical Review Board for Biomedical Research, Hanoi University of Public Health (Ref: 28/2019/YTCC-HD3). The trial’s registration number is ACTRN12619000531112. We obtained a written consent form from all participants before the interviews.