1. Sydney Medical School, Faculty of Medicine and Health, University of Sydney , Sydney , Australia
2. Blacktown Hospital, Western Sydney Local Health District , Sydney , Australia
3. Sydney Infectious Disease Institute, Faculty of Medicine and Health, University of Sydney , Sydney , Australia
4. School of Public Health, Faculty of Medicine and Health, The University of Sydney , Sydney , Australia
5. National Centre for Immunisation Research and Surveillance, The Children's Hospital at Westmead , Westmead , Australia
6. School of Population Health, University of New South Wales , Sydney , Australia
7. Dalla Lana School of Public Health, University of Toronto , Toronto, Ontario , Canada
8. Immunization, Vaccines and Biologicals Department, World Health Organization , Geneva , Switzerland