Obama vows 'vigilance' as flu spreads

WASHINGTON " President Barack Obama pledged "great vigilance" in confronting the swine flu outbreak Wednesday night as it began hitting home across the U.S. The outbreak spread to 11 states and closed schools amid confirmation of the first U.S. death " a Mexican toddler who visited Texas with his family " and the confinement of dozens of Marines after one came down with the disease in California.

Some 100 schools were closed, and more might need to be shut down temporarily, Obama said, declaring, "This is obviously a very serious situation." The total confirmed cases in the U.S. rose to nearly 100, with many more suspected.

At a prime-time news conference, Obama said health officials weren't recommending closing the border with Mexico, where the strain of the flu is believed to have originated, even though some lawmakers have called for such a course.

From the standpoint of health professionals, "it would be akin to closing the barn door after the horses are out, because we already have cases here in the United States," Obama said.

Instead, he said his administration had ramped up screening efforts and made sure needed medical supplies were on hand. "The key now is to just make sure we are maintaining great vigilance, that everybody responds appropriately when cases do come up. And individual families start taking very sensible precautions that can make a huge difference."

He praised the Bush administration for making preparations for such a crisis, including stockpiling 50 million doses of antiviral medications.

"Because this is a new strain, we have to be cautious," Obama said. "If this was a strain we were familiar with, then I think we wouldn't see the kind of alert levels that we're seeing, for instance, with the World Health Organization."

He spoke just hours after the Geneva-based WHO, a United Nations agency, sounded its own ominous alarm, raising its alert level to one notch below a full-fledged global pandemic. Said WHO Director General Margaret Chan: "It really is all of humanity that is under threat during a pandemic."