Funding for this research was provided by:
South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation of South Africa (98918)
Received: 20 June 2019
Accepted: 12 November 2019
First Online: 9 January 2020
Ethics approval and consent to participate
: Ethics approval for the study was obtained from the University of the Western Cape Biomedical Health Committee (BM17/10/9) and the Provincial Department of Health (WC_201712_026).
: Not applicable. Table removed
: The authors declare that they have no competing interests.