How big is the pandemic hazard through infected air travelers  
Scientists at the Max Planck Institute for Informatics have calculated the role of each of the world's airports in this particular risk.

The growth of international air travel has increased the threat of pandemics. Thousands of daily flight connections carrying tens of thousands of passengers in close physical contact can rapidly transform local events into worldwide phenomena. Scientists at the Max Planck Institute for Informatics have developed an algorithm that predicts the risk of a pandemic from the connectedness of the starting airport.

Scientists in the Bioinformatics Department of the MPI for Informatics in Saarbrücken can model how diseases or social phenomena spread over networks.
    They have developed a measure for each node's influence in a network. The metric, termed expected force, approximates the expected force of infection a node generates by summarizing the size, density, and diversity of the node's neighborhood. The metric assigns each node a score between 0 and 100. A node's expected force has over 90 percent correlation with its potential to trigger a spreading cascade. Twitter retweets are an example of a spreading cascade on a social network. In the case of infectious diseases on a global net-work, a spreading cascade generates a pandemic.
    Dr. Glenn Lawyer applied this metric to the worldwide network of air transportation and made the results available on a web page. The expected force (ExF) of each airport was calculated based on a database of 3,458 airports connected by 68,820 scheduled commercial routes and featuring 171 different aircraft types. Airport ExF values account for the number of flight routes to other airports as well as the seating capacity of the planes on each route.  Highly interconnected airports such as Frankfurt, Atlanta, or Beijing have an ExF close to 100. Extremely remote airports, such as Mount Pleasant on the Falkland Islands, have an ExF near zero.
    "The web-enabled tool lets users explore how contagion spreads within the world airline network," says Dr. Lawyer. "You can see how the starting point affects the probability of worldwide impact." The web page shows that the spread is slow until it reaches the core of the network. From this point, it explodes worldwide. The web page offers two modes: SI mode assumes a pandemic occurs and simulates the delay until the network core is saturated; in the SIS mode, a pandemic only occurs if the disease can reach enough nodes be-fore the initial nodes recover. The simulation measures the probability of a pandemic happening.

Further Information at:

Dr. Glenn Lawyer
Max-Planck-Institut für Informatik
Tel.: +49.681.9325-3007

Computer Science on the Saarland University Campus
The Max Planck Institute for Informatics is just one of several institutes on Saarland Univer-sity's campus devoted to research in computer science. In the direct vicinity are also located: the Department of Computer Science of Saarland University, the Max Planck Institute for Software Systems, the Center for Bioinformatics, the Center for IT-Security, Privacy and Accountability, the recently renewed Cluster of Excellence "Multimodal Computing and Interaction", the German Research Center for Artificial Intelligence (DFKI), and the Intel Visual Computing Institute.

Press contact:
Bertram Somieski (
Max Planck Institute for Informatics
Max Planck Institute for Software Systems
Joint Administration
 - public relations -
Tel +49.681.9325-5710