Funding for this research was provided by:
London School of Hygiene and Tropical Medicine
Received: 13 October 2016
Accepted: 18 January 2018
First Online: 1 February 2018
Ethics approval and consent to participate
: Ethical clearance was obtained from the London School of Hygiene and Tropical Medicine Ethical Committee, UK (reference 6503) and the Kenyatta National Hospital Ethical Review Committee, Kenya (reference KNH-ERC/A/402). Either parents or a primary guardian signed the consent forms.
: Not applicable.
: The authors declare that they have no competing interests.
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