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. DISCUSSION: The ACIR has the potential to measure immunisation coverage at any practice or local level with accuracy and timeliness. With full provider participation, the ACIR is capable of identifying areas of low immunisation coverage for targeted interventions and will play a key role in the current measles campaign, the General Practice Immunisation Incentives scheme and in payments to parents. Achieving the highest possible completeness and timeliness of the ACIR is in the interests of providers, consumers and health planners.