Received: 20 May 2019
Accepted: 30 January 2020
First Online: 5 March 2020
Ethics approval and consent to participate
: This study was approved by the Institutional Ethics Committee for Research on Human Health of the University of Douala (N° IEC-UD/454/02/2016/T). Administrative clearance was obtained from the authorities of the Douala General Hospital. Confidentiality, anonymity and privacy of all records were guaranteed at all levels of this study by using only specific codes. Written informed consent was obtained from all study participants before inclusion. For minors included in this study, written informed consent to participate was obtained from the parents/guardians in addition to assent from children aged 7 and above.
: Not applicable.
: The authors declare that they have no competing interests.