Funding for this research was provided by:
Muhimbili University of Health and Allied Sciences
Received: 19 June 2016
Accepted: 6 February 2018
First Online: 13 February 2018
Ethics approval and consent to participate
: The study received ethical approval from the Research Ethics Review Committee of Muhimbili University of Health and Allied Sciences. A written informed consent to participate into the study was obtained from the parents/guardians of the selected children prior to the study. Children provide assent to participate.
: Not applicable
: The authors declare that they have no competing interest.
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