This report could not have been prepared without the collaboration of a large number of organisations throughout Australia. The ongoing contribution of all collaborating organisations listed in the Acknowledgements section of the report to national surveillance for HIV, viral hepatitis and sexually transmissible infections is gratefully acknowledged. Unless specifically stated otherwise, all data provided in the report are to the end of 2017, as reported by 31 March 2018. All data in this report are provisional and subject to future revision. The Kirby Institute is funded by the Australian Government Department of Health and is affiliated with the Faculty of Medicine, UNSW Sydney. The Surveillance, Evaluation and Research Program at the Kirby Institute is responsible for the public health monitoring and evaluation of patterns of transmission of blood-borne viral and sexually transmissible infections and is a research associate of the Australian Institute of Health and Welfare.