Are we ready for swine flu's second wave? No one really knows

With kids back in school and winter on its way, swine flu is expected to spread big time. Some forecasts warn the H1N1 virus could potentially infect half the U.S. population by the end of the year. The question is, are we ready?

The H1N1 virus first emerged in Mexico earlier this year, setting off panic around the globe. But the initial scare subsided after the virus turned out to be less severe than originally feared. Still, it has spread at an alarming rate, sickening children and young adults more frequently than the typical seasonal flu. And now with the second wave starting to hit, officials still don't agree on how serious it will be. In short, they're racing against time to meet an enemy who remains a rapidly moving target.