About the Authors
Department of Community Medicine and School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
Department of Epidemiology and Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
Statistics, Modelling, and Bioinformatics Department, Centre for Infections, Health Protection Agency, London, United Kingdom
ML received consulting fees from the Pandemic Flu Registry, which is sponsored in part by Roche.
ICMJE criteria for authorship read and met: JTW GML ML BSC SR. Agree with the manuscript's results and conclusions: JTW GML ML BSC SR. Designed the experiments/the study: JTW GML SR. Analyzed the data: JTW BSC. Collected data/did experiments for the study: JTW. Wrote the first draft of the paper: JTW SR. Contributed to the writing of the paper: JTW GML ML BSC SR. Collected and analyzed aviation network data: BSC.