Received: 18 October 2019
Accepted: 13 January 2020
First Online: 21 January 2020
Ethics approval and consent to participants
: The ethical approval was granted by the IHI ethical review board and the National Institute for Medical Research ethical committee (number NIMR/HQ/R.8c/Vol.II/370). Assent and written informed consent was obtained from participants and their parents/guardians, respectively.
: Not applicable.
: The authors declare that they have no competing interests.