Received: 25 March 2019
Accepted: 9 October 2019
First Online: 22 October 2019
Ethics approval and consent to participate
: This study was ethically reviewed and approved by the University of KwaZulu-Natal Biomedical Research Ethics Committee (approval number BE005/15). This is a literature review, there were no study participants. Hence consent to participate was not necessary.
: Not applicable, no individual data was used.
: The authors declare that they have no competing interests.