1. WHO Collaborating Centre for Reference and Research on Influenza, Peter Doherty Institute for Infection and Immunity, 792 Elizabeth St, Melbourne, Victoria 3000, Australia
2. School of Population and Global Health, University of Melbourne, Australia Fielding School of Public Health, University of California, Los Angeles, CA, USA
3. WHO Collaborating Centre for Reference and Research on Influenza, Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
4. School of Public Health, Texas A&M University, College Station, TX, United States; School of Public Health, Curtin University, Perth, Western Australia, Australia, and Wesfamers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Crawley, Western Australia, Australia