1. Division of Virology, Faculty of Health Sciences, University of The Free State, Bloemfontein, 9301, Free State, South Africa
2. Free State Department of Health, Bloemfontein, 9301, Free State, South Africa
3. Department of Biostatistics, Faculty of Health Sciences, University of The Free State, Bloemfontein, 9301, Free State, South Africa
4. DST-NRF Centre of Excellence in Epidemiological Modelling & Analysis (SACEMA), Stellenbosch University, Stellenbosch, 7600, Western Cape, South Africa
5. Division of Virology, National Health Laboratory Service, Bloemfontein, 9301, Free State, South Africa