Adherence to HIV pre-exposure prophylaxis in New South Wales, Australia

Pre-exposure prophylaxis (PrEP) is a highly efficacious HIV prevention strategy. The caveat, however, is that PrEP requires high adherence to antiretroviral medications during periods when a person is at risk of acquiring HIV. Identifying who is at risk of HIV and ensuring adequate coverage during these risk periods is a key challenge of PrEP implementation. The overarching objective of this thesis was to examine adherence to PrEP among gay and bisexual men (GBM) in New South Wales, Australia. This body of research comprises four projects. Data for three projects came from the PrELUDE Demonstration Project (2014 – 2017), while data for the fourth project was drawn from SIN-PrEP (2015 – 2018). The first project assessed the NSW PrEP guidelines and found that individuals at high risk of HIV could be identified and enrolled into a PrEP demonstration project. The second project investigated PrEP dosing preferences and found that one-third of GBM expressed a preference for non-daily PrEP. A preference for taking daily PrEP was associated with lower levels of education, having an HIV-positive partner, and rating oneself better at taking medications. The third project compared four different adherence measures and found that in our setting, facilitated recall to clinicians was as good as biological measures in identifying adherent individuals. Over 90% of participants remaining under follow-up after 12 months reported taking seven PrEP pills per week throughout the year. A generalised estimating equation model identified that practices such as group sex were associated with taking daily PrEP. The fourth project used qualitative data from interviews with current and previous PrEP users to explore in-depth issues relating to PrEP adherence. Although most participants reported encountering barriers to PrEP use, they had developed effective strategies to ensure that high levels of adherence to PrEP could be maintained. This thesis assesses the interplay between social, behavioural, and biomedical factors that impact PrEP adherence, and how the influence of each of these factors may fluctuate during PrEP use. The high level of adherence in this cohort I have described through this thesis underpins the success of PrEP as an HIV prevention intervention in GBM in Australia