Funding for this research was provided by:
Poliomyelitis Research Foundation (16/83, 17/11)
National Research Foundation (100442)
Text and Data Mining valid from 2019-11-08
Received: 7 March 2019
Accepted: 29 October 2019
First Online: 8 November 2019
Ethics approval and consent to participate
: An ethics waiver (ref: W-CBP-180305-02) was applied for and granted by the Human Research Ethics Committee (Medical), Faculty of Health Sciences, University of the Witwatersrand.
: Not applicable.
: The authors declare that they have no competing interests.