Movies like Contagion and Outbreak play on our fears of enclosed spaces and portray airplanes—with their tight quarters and recirculated air—as major players in the spread of contagious disease. But rather than the planes, a it’s airports themselves that may deserve a closer look.
Epidemiologists and other public health specialists know that international travel plays a major role in the rapid spread of epidemics such as SARS and the swine flu (H1N1) virus. But research to date has largely focused on the later stages of disease, analyzing those cities that end up experiencing the most infections. The new model, developed by researchers at the Massachusetts Institute of Technology, aims to understand the spread of infection during the first few days of an outbreak so as to better understand how to strategically treat patients and even prevent it from expanding into pandemic proportions.
Building on the scientists’ prior work—which examines how fluids flow through fractured rock and how cellphone and other useage data can track and predict human movement—the new research looked at people’s travel patterns as they move among airports. Unlike earlier studies that assumed random movement, this one accounts for the fact that travelers usually fall into patterns that are reproducible and predictable, similar to the way fluids flow through cracks in solid rock. It also incorporates airport locations and their waiting times.
The results implicate New York City’s John F. Kennedy airport, Los Angeles International, and Honolulu International as the three airports in the country most likely to influence the spread of contagious disease. While they’re not the busiest in terms of flights or total passenger traffic, the number of international connections they provide create ideal hubs from which epidemics can rapidly disperse to multiple continents.
Knowing which airports serve as transmission hotspots can be essential in developing the best strategies for treatment and vaccine distribution during the earliest stages of an epidemic. "Characterizing early-time behavior of epidemic spreading is critical to inform decisions during public-health emergencies, and to design regulations aimed at mitigating global pandemics," the authors write. During an outbreak, such knowledge could help change the hazards of international travel from public-health worker’s nightmare into a strategic advantage.