Background

The COVID-19 pandemic represented an unprecedented health emergency in Australia and around the world, with substantial individual and health system impacts (Moynihan et al. 2021). COVID-19 is a communicable respiratory disease caused by SARS-CoV-2, a member of the coronavirus family. It commonly causes fevers and cough that can lead to pneumonia and respiratory distress. Some people can subsequently experience post COVID-19 condition, a chronic multisystem illness that develops in some people following infection and can last for months or years (Soriano et al. 2022).

COVID-19 in Australia

The first confirmed case of COVID-19 was reported in Australia on 25 January 2020 (Hunt 2020). By 12 March 2020, 140 cases had been confirmed in Australia (WHO 2020). A human biosecurity emergency response was subsequently issued, and a range of public health and social measures were established to contain the spread of SARS-CoV-2. More information on the timeline of the COVID-19 response in Australia is available from the AIHW’s COVID-19 topic summary (AIHW 2024b).

There have been several different COVID-19 ‘waves’ corresponding to the emergence of different variants and sub-variants of SARS-CoV-2 as it adapts and changes over time. In the first 3 years of the pandemic, the majority of COVID-19 notifications occurred from early 2022 onwards when the Omicron variant dominated (AIHW 2024b, Department of Health and Aged Care 2024).

Although the end of the emergency response was declared on 20 October 2023, COVID-19 remains an important issue particularly with older and/or at-risk individuals, with a large wave occurring at the end of 2023 and into 2024 (VRDEST 2024).

COVID-19 Register: using linked data to monitor COVID-19

The pandemic demonstrated the need for strengthened national data infrastructure in Australia to inform decision making and assist with current and future evidence-based planning and policy setting (Basseal et al. 2022). Through data linkage, the health service use and health outcomes of individuals affected by COVID-19 can be monitored and tracked over time.

The COVID‑19 Register (the Register) is the largest source of linked COVID‑19 case information in Australia that researchers can access to explore these questions in an Australian setting. It consists of de-identified COVID-19 case data from the National Notifiable Diseases Surveillance System (NNDSS) derived from COVID-19 notifications data from state and territory notifiable disease registers (from 7 out of 8 participating states and territories) linked to a range of administrative health data sets, including the National Death Index (NDI), the National Hospital Morbidity Database (NHMD), the Australian Immunisation Register (AIR), the Medicare Benefits Schedule (MBS), the Pharmaceutical Benefits Scheme (PBS) and several others (AIHW 2024a) (see Technical notes for details on data source and coverage).

Large health databases that link COVID‑19 case information to administrative datasets have been used in international studies to assess the impacts of COVID-19, including health care utilisation and mortality (Murch et al. 2022).

About this report

The focus of this report is to explore hospitalisation and mortality outcomes for people with a COVID-19 notification to the end of 2022. This report:

  • outlines COVID-19 notifications in Australia and notified reinfection rates from the start of the pandemic to the end of 2022
  • investigates hospitalisations (including intensive care and continuous ventilatory support) and deaths following a COVID-19 diagnosis during the height of the pandemic (Omicron period)
  • provides an overview of COVID-19 vaccination and antiviral use in Australians experiencing these outcomes
  • presents findings for population groups including by age, sex, remoteness area of residence and socioeconomic groups based on areas of usual residence.

To assist in interpreting findings, 95% confidence intervals

A range determined by variability in data, within which there is a specified (usually 95%) chance that the true value of a calculated parameter lies.

have been included in selected figures and data tables 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). In this report, when confidence intervals of two different estimates do not overlap, the difference between estimates is likely to be statistically significant. Further, there are several important considerations to note (such as data quality and data availability) when interpreting information presented in this report, see Technical notes for details.


This report is a collaboration between the Australian Institute of Health and Welfare (AIHW) and the National Centre for Immunisation Research and Surveillance (NCIRS).

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