The University of Hong Kong's Department of Microbiology is recognized around the world for its achievements in the study of infectious diseases, particularly in communicable diseases that are prevalent in this region. It has a cohesive team of clinical microbiologists, clinicians and basic scientists who have helped to bring emerging infectious diseases, notably avian flu and SARS, under control.

Professor Yuen, who graduated from the University of Hong Kong in 1981 and heads the Department of Microbiology, has the rare distinction of being a surgeon, physician and microbiologist. He has achieved spectacular success in these three areas. He has the unusual honor of being Fellows of the Hong Kong College of Pathologists, Surgeons and Physicians. He has also received Fellowships at the American College of Physicians, the Hong Kong College of Physicians, and the Royal College of Physicians in both Edinburgh and London.

Widely known among specialists in infectious diseases, Professor Yuen catapulted to world fame in the dark days of 2003 when the outbreak of Severe Acute Respiratory Syndrome, or SARS, gripped the globe. He led the team at the University of Hong Kong that first discovered the agent causing SARS, the SARS coronavirus, thus leading to measures that were crucial to containing the outbreak of the disease. He and his team went on to pioneer other developments in the diagnosis, management and control of SARS. Much earlier, in 1997, Professor Yuen was instrumental in developing rapid tests for avian influenza A H5N1, when the disease first broke out in Hong Kong. In 2004, he was honored with the Silver Bauhinia Award for his contributions to the control of emerging infectious diseases.

Professor Yuen has also led his team in the discovery of other disease agents, including the novel coronavirus HKU1, Laribacter hongkongensis, and other bacteria. He has published more than 300 papers in renowned journals throughout the world, including the Lancet, with over 3000 citations.

True to his calling as a microbiologist, physician and surgeon, he spends half his time seeing patients with important medical problems related to emerging infectious diseases, and half researching and teaching the scientific solutions to the problems.