Chair Professor of Paediatrics and Doris Zimmern Professor in Community Child Health of The University of Hong Kong (HKU)
Member of the WHO (WPRO) Technical Advisory Group for Immunisation and Vaccine Preventable Diseases
Member of the Advisory Panel on COVID-19 Vaccine for the HKSAR Government
Chair of Scientific Committee on Vaccine Preventable Diseases
Chair of Working Group on Pneumococcal Vaccination at initiated universal childhood PCV vaccination
Introduce the universal screening for maternal HIV infection as Chair of the Scientific Committee on AIDS
Founding President of the Asia Pacific Society for Immunodeficienc