Received: 8 July 2019
Accepted: 15 September 2020
First Online: 5 November 2020
Ethics approval and consent to participate
: Informed written consent was obtained from all participants after explaining the purpose of the study. Participants, who were under 16 years old, informed written consent for the study was obtained from their parent or guardian. Ethical approval for the study was obtained by the Ethical Review Committee Faculty of Medicine, University of Kelaniya, Sri Lanka (Ref No: 193/07/2017).
: This research does not contain any individual data, images or videos. The institutional consent form is available.
: All authors declare that they have no competing interests.