Coverage information
The Australian Childhood Immunisation Register
The Australian Childhood Immunisation Register (ACIR) was established on 1 January 1996, and includes all children under the age of 7 years enrolled in Medicare. Participation in the ACIR is opt-out so it constitutes a nearly complete population register, as approximately 99% of children are registered with Medicare by 12 months of age. Children not enrolled in Medicare can also be added to the ACIR via a supplementary number. Since 2001, immunisations given overseas may be recorded if a provider endorses their validity. Data are transferred nightly from the Medicare database to the ACIR when a recognised immunisation provider supplies details of an eligible immunisation either through the Internet using the Medicare Australia website or by submitting paper encounter forms which are scanned at a central location. The existence of medical contraindications and conscientious objection to immunisation is also recorded on the ACIR. All vaccination records for a child remain on the register indefinitely, but no new immunisation encounter records are added after the 7th birthday.
For an immunisation to be recorded on the Register as a valid dose, it must be given in accordance with current National Health and Medical Research Council guidelines published in The Australian Immunisation Handbook. Notifications falling outside these guidelines or duplicate notifications prompt an enquiry with the provider and, if their validity cannot be established, they are rejected.
Measuring immunisation coverage using the Australian Childhood Immunisation Register
The cohort method has been used for calculating coverage at the population level (national and state or territory) since the ACIR's inception, with each cohort defined by date of birth in 3-month age groups. Cohort immunisation status is assessed at 12 months of age (for vaccines due at 6 months), 24 months of age (for vaccines due at 12 months), and 5 years of age (for vaccines due at 4 years). A minimum 3-month lag period is allowed for late notification of immunisations to the Register, but only immunisations given on or before a child's 1st, 2nd or 5th birthday are considered. If a child's records indicate receipt of the last dose of a vaccine that requires more than 1 dose to complete the series, it is assumed that earlier vaccinations in the sequence have been given. This assumption has been shown to be valid.
The proportion of children designated as 'fully immunised' is calculated using the number of Medicare-registered children completely immunised with the vaccines of interest by the designated age as the numerator and the total number of Medicare-registered children in the age cohort as the denominator. 'Fully immunised' at 12 months of age is defined as a child having a record on the ACIR of 3 doses of a diphtheria (D), tetanus (T) and pertussis-containing (P) vaccine, 3 doses of polio vaccine, 2 or 3 doses of PRP-OMP containing Haemophilus influenzae type b (Hib) vaccine or 3 doses of any other Haemophilus influenzae type b (Hib) vaccine, and 2 or 3 doses of Comvax hepatitis B vaccine or 3 doses of all other hepatitis B vaccines. 'Fully immunised' at 24 months of age is defined as a child having a record on the ACIR of 3 doses of a DTP-containing vaccine, 3 doses of polio vaccine, 3 or 4 doses of PRP-OMP containing Haemophilus influenzae type b (Hib) vaccine or 4 doses of any other Haemophilus influenzae type b (Hib) vaccine, 3 or 4 doses of Comvax hepatitis B vaccine or 4 doses of all other hepatitis B vaccines, and 1 dose of a measles, mumps and rubella-containing (MMR) vaccine. 'Fully immunised' at 5 years of age is defined as a child having a record on the ACIR of 4 or 5 doses of a DTP-containing vaccine, 4 doses of polio vaccine, and 2 doses of an MMR-containing vaccine.
Table 1 shows the Australian National Immunisation Program Schedule (NIPS) in 2008. Only those vaccines that were on the schedule prior to 1993 are considered when determining whether a child is 'fully immunised' for the calculation of coverage rates and payment of parental and provider incentives. The Australian Government had not made a decision to include vaccines added after this date in the assessment of vaccination status.
| Australian National Immunisation Program Schedule for Children in 2008 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Age | Vacinne | |||||||
| Birth | Hep B | |||||||
| 2 months | Hep B | DTPa | Hib | Polio | 7vPCV | Rotavirus | ||
| 4 months | Hep B | DTPa | Hib | Polio | 7vPCV | Rotavirus | ||
| 6 months | Hep B | DTPa | Hib* | Polio | 7vPCV | Rotavirus€ | ||
| 12 months | Hib | MMR | Hep A± | |||||
| 18 months | VZV | Hep A§ ± | 23vPPV± | |||||
| 24 months | Hep A§ | 23vPPV§ | ||||||
| 4 years | DTPa | Polio | MMR | |||||
* 3rd dose of Hib vaccine at 6 months of age is dependent on vaccine brand used in state or territory
† 3rd dose of rotavirus vaccine at 6 months of age is dependent on vaccine brand used in state or territory
± Aboriginal and Torres Strait Islander children in Western Australia and the Northern Territory
§ Aboriginal and Torres Strait Islander children in Queensland and South Australia
An immunisation coverage annual report has been prepared by NCIRS and published in Communicable Diseases Intelligence (CDI) in 2009. The first report can be found on the Department of Health and Ageing (CDI) website.
Research Group Coordinator
Brynley Hull
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