Livescience has a sobering summary of a US avian flu pandemic simulation that has the flu infecting the entire continental US after only 90 days (starting with 10 highly infectious influenza cases in Los Angeles). In addition to concluding that the production of a modestly effective vaccine ahead of time is preferable to waiting to see what the exact strain turns out to be, the researchers also stated that quarantines, school closures, and travel restrictions are the obvious means to slow the spread.
Of course, disrupting our social and economic networks via such government imposed means (as well as by the pandemic itself), will have drastic consequences from the local to global levels. As a species, we're regionally and globally integrated at a scale never seen before in human history. The disruption of our social and economic networks will probably have longer lasting social, cultural, and economic consequences than the pandemic itself, depending on the severity.