Dr Nancy Leung is an Assistant Professor in the Division of Epidemiology and Biostatistics at the School of Public Health, The University of Hong Kong. Her research focuses on the epidemiology of respiratory virus infections, and she serves as Principal Investigator for several community-based longitudinal observational cohorts, randomised vaccine trials, and household transmission studies involving over 4,000 participants. These studies investigate individual and population immunity, vaccine response, transmission, and disease burden associated with influenza, COVID-19, and other respiratory viruses. She is interested in adopting causal inference analysis on data from these studies. Dr Leung has taught an introductory epidemiology course at the graduate level (class size 200+) and supervised research postgraduates.

Dr Leung's research has been recognised globally, including being featured as one of the "Five science stars making their mark in China" by Nature Index. She has received two Best Abstract Awards and three Fellowships for her research (h-index of 18 with 3,640+ citations, including 2 Highly Cited Papers), and her work was highlighted as a Research Case by the Hong Kong government. Dr Leung was Co-Chair/ Member of two WHO expert advisory groups on SARS-CoV-2 indoor airborne risk assessment (ARIA) and standardising terminology for pathogen transmission through the air (TTAT). Dr Leung currently serves as an Editor for the International Journal of Epidemiology (IJE), and is a popularly elected Council member of the International Society for Influenza and other Respiratory Virus Diseases (ISIRV), one of the largest international societies on respiratory virus research.

Dr Leung has 10+ years of experience on multinational and interdisciplinary collaborative research, with funding support from major local and international grants including NIH R01/U01. She has reviewed articles for journals across multiple disciplines, including JAMA, BMJ, Lancet Microbe, Nature Microbiology, Science Translational Medicine, American Journal of Epidemiology, Frontiers in Immunology, BMJ Global Health, and American Journal of Infection Control. She has also reviewed funding proposals for agencies such as the UK Medical Research Council and Wellcome Trust.

Dr Leung had diverse research training in epidemiology, immunology and virology. She conducted wet-lab experiments to study the molecular mechanism of antibody-dependent enhancement of SARS (MPhil, HKU-Pasteur Research Centre). She designed and set up hospital-based field studies in Hong Kong and mainland China to examine the aerosol transmission of influenza, coronavirus and other respiratory viruses, and community-based cohort studies and randomised vaccine trials to investigate the disease burden of influenza, COVID-19 and RSV and effects of repeated vaccination (PhD/postdoc, HKU School of Public Health). She adopted causal inference methods to evaluate vaccine correlates of protection to inform global health policies (Takemi Fellow, Harvard T. H. Chan School of Public Health). Dr Leung has a strong interest in field epidemiology and has designed electronic systems for data capture and quality control, specimen tracking, and workflow monitoring to effectively manage large-scale studies.

Fellowships and Awards:

1. Takemi Fellowship Program in International Health, Harvard T. H. Chan School of Public Health, United States, 2022 (as Visiting Scholar at Department of Global Health and Population, and CAUSALab/ Center for Communicable Disease Dynamics, Department of Epidemiology)
2. Research Fellowship Scheme, Health and Medical Research Fund (HMRF), Hong Kong, 2021
3. Faculty Outstanding Research Output Award, LKS Faculty of Medicine, The University of Hong Kong, 2021
4. Best Poster Award in the category ‘Public Health’, Options for the Control of Influenza X, 2019
5. Best Abstract in the category ‘Infection Control’, 17^th Asia-Pacific Congress of Clinical Microbiology and Infection cum 8^th International Infection Control Conference, 2018
6. Sino-British Fellowship Trust Visitorship, Sino-British Fellowship Trust, United Kingdom, 2016 (for academic visit at University College London)

1. Leung NHL* & Milton DK. New WHO proposed terminology for respiratory pathogen transmission. Nat Rev Microbiol 2024; 22:453-4.
   [2023 IF 69.2, ranked 1/161 (Q1) in Microbiology; Times cited: 1]
2. Leung NHL*, Cheng SMS*, Cohen CA*, Martín-Sánchez M, Au NYM, Luk LLH, Tsang LCH, Kwan KKH, Chaothai S, Fung LWC, Cheung AWL, Chan KCK, Li JKC, Leung YWY, Ng YY, Kaewpreedee P, Jia JZ, Ip DKM, Poon LLM, Leung GM, Peiris JSM, Valkenburg SA, Cowling BJ. Comparative antibody and cell-mediated immune responses, reactogenicity and efficacy of homologous and heterologous boosting with CoronaVac and BNT162b2: a randomized trial (the Cobovax study). Lancet Microbe 2023;4(9):e670-e82.
   [2023 IF 20.9, ranked 2/132 (Q1) in “Infectious diseases”; Times cited: 8]
3. Leung NHL*. Transmissibility and transmission of respiratory viruses. Nat Rev Microbiol 2021; 19(8): 528-45.
   [2023 IF 69.2, ranked 1/161 (Q1) in Microbiology; Times cited: 484]
   (Highly Cited Paper)
4. Xiao C*, Leung NHL*, Cheng Y*, Lei H, Ling S, Lin X, Tao R, Huang X, Guan W, Yang Z, Cowling BJ, Zanin M, Wong S-S. Seroprevalence of antibodies to SARS-CoV-2 in Guangdong Province, China between March to June 2020. Pathogens 2021; 10:1505. (*Joint first author)
   [2023 IF 3.3, ranked 70/161 (Q2) in Microbiology; Times cited: 1]
5. Leung NHL*, Chu DKW, Shiu EYC, Chan KH, McDevitt JJ, Hau BJP, Yen HL, Li Y, Ip DKM, Peiris JSM, Seto WH, Leung GM, Milton DK, Cowling BJ. Respiratory Virus Shedding in Exhaled Breath and Efficacy of Face Masks. Nat Med 2020; 26(5): 676-80.
   [2023 IF 58.7, ranked 1/189 (Q1) in Medicine, Research & Experimental; Times cited: 1,647]
   (Highly Cited Paper; Altmetric score Top 40 of all time; Described as one of 2020’s most significant coronavirus research papers by Nature Podcast)
6. Shiu EYC, Huang W, Ye D, Xie Y, Mo J, Li Y, Cowling BJ, Yang Z, Leung NHL^†. Frequent recovery of influenza A but not influenza B virus RNA in aerosols in pediatric patient rooms. Indoor Air 2020; 30(5): 805-15. (†Senior/Corresponding author)
   [2023 IF 4.3, ranked 47/403 (Q1) in Public, Environmental & Occupational Health; Times cited: 11]
7. Fong MW, Leung NHL, Xiao J, Chu DKW, Cheng SMS, So HC, Li Y, Ip DKM, Peiris JSM, Cowling BJ. Presence of influenza virus on touch surfaces in kindergartens and primary schools. J Infect Dis 2020; 222(8): 1329-33.
   [2023 IF 5.0, ranked 15/132 (Q1) in Infectious Diseases; Times cited: 18]
   (Editor’s Choice)
8. Lim WW, Leung NHL^†, Sullivan SG, Tchetgen Tchetgen EJ, Cowling BJ. Distinguishing causation from correlation in the use of correlates of protection to evaluate and develop influenza vaccines. Am J Epidemiol 2020; 189(3): 185-92. (†Corresponding author)
   [2023 IF 5.0, ranked 33/403 (Q1) in Public, Environmental & Occupational Health; Times cited: 9]
9. Leung NH*, Xu C, Ip DK, Cowling BJ. Review Article: The Fraction of Influenza Virus Infections That Are Asymptomatic: A Systematic Review and Meta-analysis. Epidemiology 2015; 26(6): 862-72.
   [2023 IF 4.7, ranked 40/403 (Q1) in Public, Environmental & Occupational Health; Times cited: 105]
10. Yip MS*, Leung NH*, Cheung CY, Li PH, Lee HH, Daeron M, Peiris JS, Bruzzone R, Jaume M. Antibody-dependent infection of human macrophages by severe acute respiratory syndrome coronavirus. Virol J 2014; 11(1): 82. (*Joint first author)
    [2023 IF 4.0, ranked 14/41 (Q2) in Virology; Times cited: 188]