Fri, 12/06/2019 | News

New NCIRS report: Exploratory analysis of the first 2 years of adult vaccination data recorded on AIR

NCIRS conducted an exploratory analysis of adult vaccination data for selected vaccines recorded on the Australian Immunisation Register (AIR) for the first 2 years of its establishment (October 2016 – September 2018). 

Overall it was found that population-level vaccination uptake recorded on AIR substantially underestimates true uptake in adults, which could be up to double that recorded on AIR. There was considerable geographic variation in vaccine uptake at both state/territory and Primary Health Network levels, which may reflect true differences in uptake and/or differences in completeness of reporting.

A higher level of vaccination uptake was recorded in Aboriginal and Torres Strait Islander people, for both influenza and zoster vaccines. 

It is noted that AIR data completeness should improve over time as GP practice management software packages are updated and as registration and transfer of data from other provider groups expands. 

Providers are encouraged to submit all immunisation data to AIR to ensure accuracy of AIR information at both the individual and the population level.

Report highlights include the following:

Influenza vaccination coverage 

  • The proportion of adults aged ≥18 years recorded on AIR as having received a dose of influenza vaccine increased from 11.5% in 2017 to 18.8% in 2018.
  • Recorded uptake was highest in the ≥65 years age group at 31.5% in 2017 and 46.3% in 2018.
  • Recorded uptake was substantially higher in Aboriginal and Torres Strait Islander adults than in non-Indigenous adults – three times higher in the 18–<65 years age groups in which all Aboriginal and Torres Strait Islander people are eligible for NIP-funded vaccine, and 64.9% for those aged ≥65 years in 2018.
  • These influenza vaccination uptake figures likely substantially underestimate true uptake because of underreporting to AIR. 
  • It is difficult to assess the level of underreporting for quadrivalent influenza vaccine which is used in the private market in large quantities. However, for enhanced- immunogenicity trivalent influenza vaccine, which is funded on the NIP for all adults aged ≥65 years and registered for use only in this age group, the number of doses recorded on AIR was 44% lower than the number distributed under the National Immunisation Program (NIP) in 2018.  

Zoster vaccination coverage 

  • Approximately 2 years after the implementation of the national zoster immunisation program, 31.2% of adults aged 70–<80 years were recorded on AIR as vaccinated at some point over the 1 October 2016 – 30 September 2018 period.
  • The proportion recorded as vaccinated was higher for Aboriginal and Torres Strait Islander adults (36.7%) than for non-Indigenous adults (31.1%).
  • AIR data show that zoster vaccination uptake peaked in May in both 2017 and 2018, likely because of older adults presenting to providers for influenza vaccination.
  • Given that over 90% of zoster vaccine doses recorded on AIR were in the target age group (adults aged 70–<80 years), it is likely that these represent largely NIP-funded vaccine.
  • True zoster vaccine uptake in Australia is likely to be considerably higher than the figures presented here, given that the number of zoster vaccine doses recorded on AIR was approximately half the number of doses distributed under the NIP over the study period.

Pneumococcal polysaccharide vaccine coverage

  • The number of pneumococcal vaccine doses given, as recorded on AIR, peaked in May in both 2017 and 2018, as with zoster vaccination, suggesting that attendance for seasonal influenza vaccination prompts concomitant zoster and pneumococcal vaccination. 
  • In all jurisdictions except the Northern Territory (NT), the highest number of doses recorded was administered to adults aged ≥65 years.
  • A much higher percentage of doses recorded was given to younger adults in the NT, likely because of the high proportion of the NT’s population that are Aboriginal and Torres Strait Islander, and the high prevalence of risk factors for pneumococcal disease among them (pneumococcal polysaccharide vaccine is funded under the NIP for all Aboriginal and Torres Strait Islander people aged ≥50 years and all aged 15-49 years who have medical risk factors).

Click here to view the full report.