A Decade of HIV Pre-Exposure Prophylaxis (PrEP) Cascade Monitoring: National Trends and Persistent Gaps in PrEP Use Among Gay, Bisexual and Queer Men and Non-Binary People in Australia.

We have monitored Australia's maturing HIV pre-exposure prophylaxis (PrEP) program for the past decade, providing a unique view of long-term implementation among gay, bisexual and queer men and non-binary people. Using two national surveys, the GBQ + Community Periodic Surveys (GCPS, 2014-2023, N = 78,378) and the PrEPARE Project (2017-2023, N = 5,278), we constructed and iteratively refined cascades to monitor PrEP suitability, awareness, use, and service engagement. The PrEPARE cascade also included willingness, provider engagement and psychosexual benefits of PrEP. By 2023, both cascades showed near-universal PrEP awareness among PrEP-suitable participants. In the GCPS cascade, PrEP use increased from < 1% of PrEP-suitable participants in 2014 to 30% in 2023, while in PrEPARE it increased from 21% in 2017 to 46% in 2023. However, in 2023, 29% of GCPS participants who were suitable and aware were not using PrEP, and 14% of PrEPARE participants who were PrEP-suitable and aware were unwilling to use it. PrEP use was lower among younger participants, bisexual and queer-identified participants compared with gay-identified participants, those outside metropolitan areas, and migrants without government-subsidised healthcare. Australia is among the few countries with repeated PrEP cascades that have been revised as implementation has evolved. We show that Australia has achieved near-universal PrEP awareness but highlight persistent inequities in uptake. Our findings demonstrate the value of long-term cascade monitoring and the need to address financial, geographic, and risk-perception barriers to close remaining gaps.