Can plane travel spread deadly viruses?

Remember H1N1 flu in 2009 and SARS in 2003? Remember the concern about airports, and how plane travel could spread newly emerging viruses and bacteria around the world rapidly? Did you see the film Contagion, which demonstrates how a killer bat virus could mutate into a killer human virus and circle the globe (by plane) in a matter of days?

Of course science fiction is not real life, and SARS, though it did spread to 37 countries, ended up spreading a lot more panic than virus and killing less than one thousand. H1N1 killed almost 300,000 people around the world, but that is less than many yearly seasonal flu strains.

Still, the lesson of airports being hubs to spread contagions as well as the panic that accompanies it remains a great concern. A new mathematical model from MIT, just published in PLoS One, reveals that JFK in New York, LAX in Los Angeles, and Honolulu International Airport would be the top three airports in terms of potential spread of a new contagion. Though Atlanta's airport actually has more flights, it is lower down on the list.

The study is more sophisticated than most mathematical models of this sort because it includes waiting times, traffic at airports, as well as the countries the airports service. Honolulu and LAX are gateways not only to the west coast of the U.S. but to the far east, where many new viruses originate. JFK is a gateway to Europe, from where a new pathogen can easily spread around the globe.

But though there are certainly lessons to be learned here about potential patterns of contagion, at the same time, as we also learned from SARS, models do not make a pandemic.

It is too easy to read this study and become unduly afraid of infectious spread on planes. Keep in mind that studies from the Centers for Disease Control have demonstrated that tuberculosis is very rarely transmitted on planes, despite the close proximity of passengers. Major diseases like malaria and dengue have never spread effectively on planes, because they require a vector (mosquitoes). The big HEPA air filters effectively eliminate the vast majority of viruses and bacteria.

So the new study on airports as hubs for pandemics is both instructive as well as anxiety-provoking and easily exaggerated. It is important to remember that fear is even more viral than the worst virus.