By Alimuddin I. Zumla, BSc, MBChB, MSc, PhD(Lond), FRCP(Lond), FRCP(Edin), Professor of Infectious Disease and International Health, University College London, Royal Free and University College, London Medical School; Director, Centre for Infectious Diseases and International Health, Windeyer Institute of Medical Sciences, University College London, London, UK; Honorary Consultant in Infectious Diseases, University College London Hospitals NHS Trust, London, UK; Honorary consultant physician, St. Luke’s Hospital for the Clergy, London; Honorary Professor, Liverpool School of Tropical Medicine, University of Liverpool, UK; Honorary Professor, Centre for International Child Health, Institute of Child Health, London, UK; Visiting Professor, University of Zambia School of Medicine, Lusaka, Zambia; Honorary Professor, University of Cape Town, Department of Medicine, Cape Town, South Africa, Member of Court of Governors, London School of Hygiene and Tropical Medicine, London, UK; Formerly, Associate Professor, Center for Infectious Diseases, University of Texas Health Science Center at Houston, School of Medicine and Public Health, Houston, TX, USA; Vice President and Council Member, Royal Society of Tropical Medicine, London, UK (2003-2006) and H. Simon Schaaf, MBChB(Stellenbosch), MMed Paed(Stellenbosch), DCM(Stellenbosch), MD Paed(Stellenbosch), Professor of Paediatrics and Child Health, Desmond Tutu Tuberculosis Centre and Department of Pediatrics and Child Health, Stellenbosch University and Tygerberg Children’s Hospital, Western Cape, South Africa.