Over the past few decades, global metapopulation epidemic simulations built with worldwide air-transportation data have been the main tool for studying how epidemics spread from the origin to other parts of the world (e.g., for pandemic influenza, SARS, and Ebola). However, it remains unclear how disease epidemiology and the air-transportation network structure determine epidemic arrivals for different populations around the globe. Here, we fill this knowledge gap by developing and validating an analytical framework that requires only basic analytics from stochastic processes. We apply this framework retrospectively to the 2009 influenza pandemic and 2014 Ebola epidemic to show that key epidemic parameters could be robustly estimated in real-time from public data on local and global spread at very low computational cost. Our framework not only elucidates the dynamics underlying global spread of epidemics but also advances our capability in nowcasting and forecasting epidemics.
Dr Joseph Wu leads the infectious disease modeling research in the HKU School of Public Health. His primary research is in influenza epidemiology and control with a focus on pandemic preparedness and response. He earned his PhD in Operations Research from MIT in 2003 and BS in Chemical Engineering from MIT in 1999. His work primarily entails developing mathematical models to assess the potential benefits and resource requirement of mitigation and surveillance strategies for communicable diseases including influenza, hand-foot-and-mouth disease, HPV infection and yellow fever. Since 2013, he has been working closely with the China CDC on the risk assessment and management of avian influenza A/H7N9 epidemics and health economic evaluation of vaccination against hand-foot-and-mouth disease in China. He is the producer of HKU's first Massive Open Online Courseware (MOOC) Epidemics which has had more than 16,000 people enrolled since its first launch on the edX platform in 2014. He is the director of the Croucher Summer Course Vaccinology for Public Health and Clinical Practice. He is an affiliated faculty member of the Center for Communicable Diseases Dynamics (CCDD) at the Harvard School of Public Health. He is an associate editor of the American Journal of Epidemiology and a Fellow of the UK’s Faculty of Public Health. He is a member of the Technical Working Group for the WHO Public Health Research Agenda for Influenza. He is a member of the Scientific Committee for the Center for Health Protection in Hong Kong. He was a recipient of Outstanding Young Researcher Award from HKU in 2015.