Received: 4 December 2019
Accepted: 15 July 2020
First Online: 22 July 2020
Ethics approval and consent to participate
: The protocol for this study was approved by the Ethics and Research Committees of the Ministry of Health of Delta, Bayelsa and Edo States with reference numbers CHW/VOL14/130, FMCY/REC/ECC/2017/OC/046 and 732/T/89 respectively. Consent to participate in this study were obtained from each parent or guardian on behalf of the participants.
: Not applicable.
: The authors declare that they have no competing interests.