Funding for this research was provided by:
Commission of Scientific Research and Innovation, Ministry of Higher Education and Scientific Research, Sudan (SRIC/2017/RP761)
Received: 7 October 2019
Accepted: 16 January 2020
First Online: 29 January 2020
Ethics approval and consent to participate
: This study was approved by the Ethical Committee of the Research Directorate, General Directorate of planning & International Health, Federal Ministry of Health, Republic of Sudan (fmoh/nhrc/rd/rec). Written signed informed consent was obtained from each participant or their guardians/parents before his/her enrolment in the study.
: Not applicable.
: The authors declare that they have no competing interests.