Evidencing work: implementing HIV pre-exposure prophylaxis and on-demand dosing in Australia

HIV pre-exposure prophylaxis (PrEP), the use of antiretroviral drugs to prevent HIV infection, was initially implemented in Australia as a daily regimen, transforming HIV prevention. However, the process of implementation, and key shifts in the delivery of PrEP, such as the introduction of on-demand (non-daily) dosing, are not well understood. This study aimed to understand how key stakeholders put PrEP into practice, and the 'evidencing work' that underpinned these processes. Evidencing work refers to how actors mobilise 'local orders of evidence' to understand and assess how an intervention, like PrEP, performs in its local context. We conducted 21 interviews in 2021-2022 with key stakeholders representing research, clinical practice, policymaking, health education and promotion, and community engagement. The analysis shows how stakeholders worked with and understood evidence, the prominence of (and departure from) clinical guidelines, and the growth in and recognition of on-demand dosing. Participants described translational, authorising, and localising evidencing work, overlapping practices necessary to create 'evidence enough' to proceed with implementation. The generation of national, local, and peer- and expertise-based evidence was particularly important to reassure participants that PrEP use was safe and effective in Australia, and to provide evidence that on-demand dosing could be successfully practiced. Encouraging localising evidencing work with less familiar prescribers (e.g. sharing peer-, patient- and expertise-based evidence about PrEP) could enable PrEP rollout and support for different dosing regimens, such as on-demand dosing.