1 Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
2 National Priority Programme, National Laboratory Services, Johannesburg, South Africa.
3 Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
4 Division of Medical Virology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa.
5 National Health Laboratory Service, Cape Town, South Africa.