Article History
Received: 22 July 2019
Accepted: 10 July 2020
First Online: 17 November 2020
Ethics approval and consent to participate
: Ethical approval was obtained from the University of Cape Town Health Sciences Research Committee and the World Health Organization Ethics Review Committee (0003034). This was a systematic review; there were no primary study subjects from whom consent needed to be obtained.
: Not applicable
: The authors declare that there are no financial or non-financial competing interests.