In a 2007 paper, [computer scientist Alessandro] Vespignani's team modelled the spread of influenza pandemics of varying severities in 3100 urban centres in 220 countries. They also looked at the effectiveness of countermeasures including vaccination, administration of antiviral drugs such as Tamiflu, and travel restrictions.
A Draconian 10-fold reduction in airline travel would delay a pandemic by only a few weeks and have no effect on its overall health impact, Vespignani's team concluded. Other measures—particularly widespread administration of antiviral drugs—proved far more effective at limiting the spread of hypothetical pandemics.
A 2006 study led by Ben Cooper at the Health Protection Agency in London, UK, suggests that travel limitations would have to be implemented extremely early in a pandemic, when just a handful of people in a city are infected, to dramatically slow the spread. And even with a dramatic 99.9 per cent drop in airline traffic, most cities will eventually succumb to an influenza pandemic, Cooper's models indicate.
According to the researchers, such restrictions aren't just ineffective. They're harmful:
Modellers have also attempted to measure the economic cost of widespread travel bans in response to pandemic flu. In 2007, a team led by Joshua Epstein of the Brookings Institution in New York estimated that a 95 per cent reduction in air travel in the US could cost about $100 billion per year, or a little less than 1 per cent of the US gross national product.