Received: 5 July 2019
Accepted: 7 January 2020
First Online: 15 January 2020
Ethics approval and consent to participate
: All information about this study was provided to parents in local languages. Written informed consent from parents for each patient in this study has been obtained. The Ethics Committee of Public Health School of University of Kinshasa approved the protocol under the number ESP/CE/027B/2011.
: Not applicable.
: The authors declare that they have no competing interests.