1. The National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases (NCIRS) Sydney, New South Wales, Australia
2. Discipline of Paediatrics and Child HealthThe Children's Hospital at Westmead, and the University of Sydney, Sydney
3. Centre for Disease Control, Northern Territory Department of Health, Darwin, NT, Australia
4. Applied Epidemiology training programAustralian National University, Canberra, Australia
5. Communicable Disease Control Branch, South Australian Department of Health and Ageing, Adelaide, SA, Australia