1. Discipline of General Practice, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
2. Adelaide Rural Clinical School, The University of Adelaide, Adelaide, Australia
3. National Centre for Immunisation Research and Surveillance, Westmead, Australia
4. Children's Hospital Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Westmead, Australia
5. School of Public Health, Faculty of Medicine, University of New South Wales, Sydney, Australia