Dr Au is a specialist in Public Health Medicine. He has worked in various areas of public health in the Department of Health since 2003. He currently serves in the Emergency Response and Programme Management Branch of the Centre for Health Protection, where his principal responsibilities encompass the development of contingency plans and the orchestration of drills and exercises to bolster public health crisis preparedness and response mechanisms. Additionally, he oversees the planning, implementation, and enhancement of various vaccination programmes. Before assuming his current role, he had worked in several areas related to disease prevention and control including epidemiological investigation of outbreaks, surveillance of communicable diseases, prevention of HIV/AIDS, environmental health and toxicovigilance.