 By rapidly rolling out this new intervention as rapidly as feasible, and following participants for up to two years on treatments, we expect a reduction in new HIV diagnoses in WA due to decreased infection in the on-treatment cohort, and to the interruption of chains of transmission to others not receiving PrEP. The rapid and large-scale roll-out of PrEP is a critical component of working towards the virtual elimination of HIV transmission by 2020. 