WASHINGTON — Closing schools won't necessarily stop the spread of swine flu.

What about the younger sister in a private day care center? And how to keep teens who are sent home from getting together at the mall or at each other's houses?

So far, only about 100 of the nation's 132,000 schools have closed. But they include schools on both coasts and in the nation's heartland, and more are likely to shut their doors in coming days. Texas officials just suspended all high school sports — smack in the middle of baseball season.

Local officials make the decisions on schools, after weighing conditions in their cities, towns and counties. But President Barack Obama says parents everywhere should start preparing for the possibility that their children may be sent home.

That would raise a whole new set of questions.

"There is a large ripple effect," acknowledged Kathleen Sebelius, Obama's newly approved health secretary. "What happens to the parents? Where do those children go? Do you close the day care center if a younger sibling is there?"

So far, closings have affected fewer than 60,000 students out of a total of 56 million enrolled nationwide in K-12 education in public and private schools. Most of the closings are individual schools, not entire systems. Most are expected to be short-term, a week or so. Some of the children who got sick are already recovering.