Notes:
- A COVID-19 related hospitalisation is a hospitalisation related in time to a COVID-19 diagnosis and has a COVID-19 ICD-10-AM diagnosis code (U07.1, U07.2). See Technical notes for further details.
- This analysis is based on people who had their first reported COVID-19 diagnosis during the Omicron wave (15 December 2021 to 1 July 2022). Hospitalisations that occur after subsequent diagnoses for the same person are not included in this analysis.
- Number of vaccine doses is calculated as the total number of COVID-19 vaccination doses recorded on the Australian Immunisation Register 14 days or more prior to diagnosis. See Technical notes for further details.
Interpreting COVID-19 related hospitalisations by vaccine dose
COVID-19 vaccination status is based on the number of COVID-19 vaccination doses recorded 14 days or more prior to a COVID-19 diagnosis, to account for a vaccination taking 14 days to become effective (see Technical notes for details). In this report, COVID-19 vaccination status is categorised into people who were:
- unvaccinated (0 doses)
- partially vaccinated (1 dose)
- vaccinated (2 or 3 or more doses).
These groups might differ from other published studies where ‘unvaccinated’ may have included people who received less than 2 doses. It should be noted the definitions of vaccination by number of doses has evolved over time based on the rollout of COVID-19 vaccines so this may not align with current definitions.
To aid in interpreting findings, 95% confidence intervals are included to show the range of uncertainty around each estimate (that is, that 95 out of 100 times the estimate will fall between the upper and lower values). A wider confidence interval band means greater uncertainty. In this report, when confidence intervals of two different estimates do not overlap, the difference between estimates is likely to be statistically significant.
When interpreting results in this report, it is important to consider:
- staged rollout of COVID-19 vaccination, where selected groups, usually those at highest risk of severe disease, were recommended and prioritised for vaccination.
- findings have not been adjusted to account for age, pre-existing health conditions and/or other characteristics (such as geographical location or living in a residential aged care facility) which may predispose these groups to vaccination or increased hospitalisation.
- people who died during the study period were included in the analysis. People who died, particularly in the oldest age groups, may be more vulnerable and susceptible to hospitalisation than others.
- data in this report cannot be used to infer vaccine effectiveness.
See Data tables to access downloadable data containing COVID-19 related hospitalisations and vaccination status.
Remoteness area and socioeconomic groups
As older people were more likely to have a COVID-19 related hospitalisation, hospitalisations among people aged 60 and over by remoteness areas and socioeconomic groups of residence of the person hospitalised were examined by vaccination status (Figure 8).
For people with a COVID-19 notification aged 60 and over in Major cities and regional areas, and across all socioeconomic groups, those who were vaccinated with at least 2 doses had fewer COVID-19 related hospitalisations compared with those who received 0 or 1 dose.
See Data tables to access downloadable data containing COVID-19 related hospitalisations and vaccination status.
