Funding for this research was provided by:
Poliomyelitis Research Foundation (13/09)
Harry Crossley Foundation
National Health Laboratory Services Research Trust (004-94518)
Text and Data Mining valid from 2018-05-08
Received: 5 January 2018
Accepted: 25 April 2018
First Online: 8 May 2018
Ethics approval and consent to participate
: Participants were recruited following written informed consent according to the Declaration of Helsinki 2008. Ethical approval for the study was obtained from the health research ethics committee at Stellenbosch University (S13/04/072).
: The authors declare that they have no competing interests.
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