HIV cascade, key indicators, and other epidemiological metrics in Australia (2004-2023): a retrospective analysis

We aimed to describe Australia's overall progress towards ending AIDS as a public health threat between 2004 and 2023 using a retrospective analysis of the HIV cascade, key indicators, and other epidemiological metrics.

We used mathematical modelling, national HIV notifications, cohort, and administrative data to calculate annual estimates for the HIV cascade of care, the number of annual new HIV infections, and related HIV epidemic metrics between 2004 and 2023, for the overall population and males and females. We used piecewise negative binomial regression to determine changes in trajectory and annual rate ratios (ARRs) for each cascade step and metric.

We estimated there were 30,010 (range: 26,700-35,220) people living with HIV in Australia at the end of 2023 with 25,650 males (85.5%) and 4080 females (13.6%). The percentage diagnosed increased slowly over time and remained below the first UNAIDS 95 target (93.0% of 30,010 people living with HIV in 2023). The percentage diagnosed and on treatment crossed the second UNAIDS 95 target in 2023, reaching 96.6% of 27,650 people diagnosed with HIV, following a large fall in the number untreated between 2010 and 2015. The percentage of people treated with a suppressed viral load first achieved the third UNAIDS 95 target in 2017 (and was 97.5% of 26,700 people on ART in 2023). Changes in the cascade gaps coincided with an increase, stabilisation, and then fall in HIV notifications and estimated new HIV infections in Australia. Most metrics showed substantial improvement over the 2004-2023 period, including during the COVID-19 era. However, there was a large increase in notifications in 2023 following the easing of COVID-19 restrictions, and the number of people living with undiagnosed HIV has remained steady. The metrics for males had very similar trends to the overall population whereas among females the HIV epidemic showed a continuous growth since 2004. Females had a smaller diagnosis gap than males (94.3% vs 91.6%) but a larger treatment gap (94.1% vs 98.2%).

While Australia saw substantial progress in the HIV cascade metrics since 2004, it is not on track to reach all 95-95-95 targets by 2025. Despite large falls in new infections, there are persistent gaps in the cascade related to diagnosis. Further efforts and investments are needed to address barriers to care and ensure the end of HIV as a public health threat in Australia.

Australian Centre for Disease Control and the Australian National Health and Medical Research Council (NHMRC).