Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, Australia. Disease Elimination Program, Burnet Institute, Melbourne, Australia. School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia. Homeless Healthcare, West Leederville, Perth, Australia. School of Public Health, Curtin University, Bentley, Australia. Department of Gastroenterology and Hepatology, Royal Perth Hospital, Perth, Australia. UWA Medical School, University of Western Australia, Perth, Australia. School of Medical and Health Sciences, Edith Cowan University, Perth, Australia. St John of God Hospital, Subiaco, Perth, Australia. Epworth HealthCare, Eastern Clinical School of Monash University, Melbourne, Australia. eResearch Office, Queensland University of Technology, Brisbane, Australia. Berry Consultants, Austin, TX, USA. Department of Infectious Diseases, The Alfred and Monash University, Melbourne, Australia. Peter Doherty Institute for Infection and Immunity, Melbourne, Australia. School of Population and Global Health, University of Melbourne, Melbourne, Australia. Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, Australia. tom.snelling@sydney.edu.au. School of Public Health, Curtin University, Bentley, Australia. tom.snelling@sydney.edu.au. Menzies School of Health Research, Charles Darwin University, Darwin, Australia. tom.snelling@sydney.edu.au. Department of Infectious Diseases, Perth Children's Hospital, Perth, Australia. tom.snelling@sydney.edu.au. School of Public Health, University of Sydney, Camperdown, Sydney, New South Wales, 2006, Australia. tom.snelling@sydney.edu.au.