Graduating with honours at the Medical Faculty, University of Hong Kong in 1970, I then joined the Medical Department of the University of Hong Kong in 1971, and have been working there since then. I started my research on liver diseases in the late 1970s. I was the co-author of the study showing the deleterious effect of prednisolone on HBsAg-positive chronic active hepatitis. In the 1980s, I was involved in various studies on the hepatitis vaccine and hepatocellular carcinomas.

I was the world's first person to conduct placebo-controlled studies of the effect of recombinant alpha2 interferon in HBsAg carrier children and in hepatocellular carcinoma. Subsequently, I concentrated on the use of nucleos/tide analogues in chronic hepatitis B, being the principle investigator for phase 3 studies of lamivudine, entecavir and telbivudine and phase 2b study of besifovir. I've been published extensively on the natural progression of chronic hepatitis B, and co-edited with Professor Stephen Locarnini two editions of the book 'Hepatitis B Virus' (International Medical Press).

I had been invited to write an editorial on tenofovir disoproxil fumarate when the phase 3 study was published, and to give the prestigious Leon Schiff State-of-the-Art Lecture at the '2005 AASLR Annual Meeting', and the Okuda Lecture Lecture at the '2017 APDW Meeting'. I'm still actively investigating the long-term effects of nucleos/tide analogues in chronic hepatitis B patients, especially the effect on cccHBV DNA. I've also been involved in the study of chronic hepatitis C, its transmission, the natural history and the use of direct acting antivirals.

There were a few colleagues whose examination techniques were sub-optimal. After 2 to 3 sessions of training for the membership examination, they quite suddenly became very efficient and competent. Such 'quantum' jumps in performances are quite frequent and always tremendously satisfying to the doctors.