The aims of this study are to estimate the effect of the medically supervised injecting room (MSIR) in North Richmond, Melbourne on primary and secondary health outcomes, amongst cohort members of The Melbourne Injecting Drug User Cohort Study (SuperMIX). Namely, these health outcomes are overdose- related ambulance attendance, emergency department attendance and oral health related quality of life (OHRQoL). This will be achieved via target trial emulation, utilising available primary and linked data.