1. Stellenbosch University; Centre for Evidence-based Health Care, Faculty of Medicine and Health Sciences; PO Box 241 Tygerberg Cape Town Western Cape South Africa 8000
2. University of Sydney; Marie Bashir Institute for Infectious Diseases and Biosecurity; Sydney Australia
3. University of Sydney; Children’s Hospital at Westmead; Sydney Australia
4. University of Cape Town/Western Cape Department of Health; P.O. Box 768 Rondebosch South Africa 7701