1. Vaccine Uptake Group Murdoch Children's Research Institute Melbourne Victoria Australia
2. Department of Paediatrics University of Melbourne Melbourne Victoria Australia
3. National Centre for Immunisation Research and Surveillance Kids Research, Sydney Children's Hospitals Network Sydney New South Wales Australia
4. The Children's Hospital at Westmead Clinical School, Faculty of Medicine and Health The University of Sydney Sydney New South Wales Australia
5. Clinical Epidemiology and Biostatistics Unit Murdoch Children's Research Institute Melbourne Victoria Australia
6. School of Psychology and Public Health La Trobe University Melbourne Victoria Australia
7. Department of General Medicine Royal Children's Hospital Melbourne Victoria Australia