1. Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
2. Influenza Program, Centers for Disease Control and Prevention, Pretoria, South Africa
3. US Public Health Service, Rockville, Maryland
4. Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases of the National Health Laboratory Service
5. School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
6. Global Immunization Monitoring and Surveillance Team, Expanded Programme on Immunization, Department of Immunization, Vaccines and Biological, World Health Organization, Geneva
7. Technical Research and Development, Novartis Pharma AG, Basel, Switzerland
8. School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg
9. Department of Paediatrics, Pietermaritzburg Metropolitan Hospitals, University of KwaZulu-Natal
10. Department of Paediatrics, Klerksdorp Hospital, North West Province
11. Emerging Vectorborne and Respiratory Virus Program, Center for Viral Zoonoses, Department of Medical Virology, University of Pretoria
12. Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand
13. Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa