A ban on domestic travel could delay the spread of a flu pandemic

A near total ban on domestic travel could delay the spread of a flu pandemic by a week or more, particularly if the outbreak originates in a regional town or small city such as Darwin, according to new modelling by Australian researchers.

Regional and inland communities could be virtually quarantined from a pandemic if travel controls are rigidly applied and introduced very early on in an outbreak, according to Dr James Wood, a lecturer at the University of Sydney.

Dr Wood, who is also a researcher at the university's National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, said: "Travel would need to be reduced to 10% to 1% of normal travel volumes to be effective."

"Even a delay of a few days or a week would give health authorities crucial time to prepare responses such as distributing anti-viral drugs and emergency resources."

Writing in the latest issue of the journal Emerging Infectious Diseases , Dr Wood and colleagues argue that as Australia is an island with a relatively low population density, travel restrictions could be particularly effective in preventing the spread of a pandemic.

"The population is concentrated in five large cities, along with smaller centres, primarily along its eastern and southern coastline. These centres are widely separated and travel between them is primarily by air."

They acknowledge the "benefits from delaying the domestic spread of an epidemic" must be balanced with the economic and social disruption that would be caused, as occurred in nations affected by the SARS virus.

The economic impacts of travel restrictions make it most suitable for small, relatively isolated areas; these areas are also less likely to have the health and other resources to respond effectively.

Their modelling also suggests that if an epidemic originates in a smaller town or a small city such as Darwin, travel restrictions would be particularly effective. "Restricting visitors from entering or leaving that town is important."

In larger centres and major cities and ports, where large volumes of international traffic are coming in, domestic travel restrictions are unlikely to be effective, they say.