1. Hunter New England Population Health, Hunter New England Area Health Service, Newcastle, NSW.
2. Epidemiology Unit, Victorian Infectious Diseases Reference Laboratory, Melbourne, VIC.
3. School of Population Health, University of Melbourne, Melbourne, VIC.
4. Public Health Unit, South Eastern Sydney and Illawarra Area Health Service, Wollongong, NSW.
5. School of Public Health and Community Medicine, University of New South Wales, Sydney, NSW.
6. Vaccine‐Preventable Disease Laboratory Network, Expanded Programme for Immunization, World Health Organization, Geneva, Switzerland.