Funding for this research was provided by:
South African Medical Research Council (494184)
Received: 21 February 2020
Accepted: 22 June 2020
First Online: 6 July 2020
Ethics approval and consent to participate
: The protocol was approved by the University of Cape Town and University of the Witwatersrand’s human research ethics committees. All participants provided written informed consent.
: The authors have no conflict of interest to declare.