Measuring immunisation coverage in Australia. A review of the Australian Childhood Immunisation Register.

BACKGROUND: Before the establishment of the Australian Childhood Immunisation Register (ACIR)- measurement of childhood immunisation coverage in Australia involved a variety of methods at varying intervals by general practice (GP) divisions- state health departments and the Australian Bureau of Statistics. Such surveys may underestimate (child health records) or overestimate (parental recall) true immunisation coverage. OBJECTIVE: The establishment of the ACIR in 1996 (a world first)- was a huge undertaking involving 15-000 immunisation providers (60% GPs) notifying over 3 million immunisations annually. This review summarises the operation of the ACIR- how it calculates coverage- the accuracy of estimates from the ACIR and how Australia's immunisation coverage compares with that of other similar countries. Currently- the accuracy of the records on the register is questioned- especially in urban areas- but available data suggest that failure to report to the ACIR is the main source of data discrepancies. DISC