"We want to make sure we are not promoting panic, but we are promoting vigilance and preparation," Obama told the gathering.

State officials welcomed the funds but had more practical questions for the feds, starting with what they learned from the chaos when swine flu first burst on the scene last spring and schools around the country closed because of sick students.

Since then, the virus has infected an estimated 1 million Americans and still is spreading, remarkable considering influenza usually can't tolerate summer's heat and humidity.

"What I need from all of you is an idea of when it is best to close, when it is necessary to close and when it's not," said Belinda Pustka, superintendent of Texas' Schertz-Cibolo-Universal City Independent School District.

"Closing school is a last resort, not a first resort," Duncan stressed, but he said schools need to plan how they'll keep students learning if they do have to close for extended periods.

An even bigger problem: When schools close and working parents need to stay home — or any worker gets sick — too often, they don't get paid, said Paul Jarris of the Association of State and Territorial Health Officials. So they come to work, spreading infection.

"How are we going to assist people who don't have benefits?" he asked.

Homeland Security Secretary Janet Napolitano said she was working with the Labor Department to address that question, and she urged employers to allow telecommuting and make other provisions should swine flu hit their workplaces this fall.

Swine flu outbreaks in the fall are all but certain given its continued spread here — 50 outbreaks in children's summer camps so far — and abroad, with major problems in parts of the Southern Hemisphere.