Funding for this research was provided by:
DST-NRF Centre of Excellence in Human Development
Claude Leon Foundation
UK Medical Research Council (MC_UU_12015/3)
NIHR Biomedical Research Centre Cambridge (IS-BRC-1215-20014)
Text and Data Mining valid from 2018-06-25
Received: 30 November 2017
Accepted: 14 June 2018
First Online: 25 June 2018
Ethics approval and consent to participate
: Ethical approval was obtained from the Human Research Ethics Committee of the University of the Witwatersrand (ethics number M150632). All participants gave written and informed consent for participation in this study.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.