The Centers for Disease Control said today that schools should not close for the H1N1/swine flu virus unless a large number of students are infected.

The guidelines are a little different than ones issued earlier in the year.

In addition to recommendations on school closures, CDC officials also advised parents that sick children can return to school 24 hours after a fever is gone. Previously the recommendation had been that students stay out of school for a full week.

The information on keeping kids out of school came from former city Health Commissioner Tom Frieden, who is now head of the CDC, and Department of Homeland Security Secretary Janet Napolitano.

“The guidance we’re announcing today will give local school officials the tools they need to make informed decisions about how to decrease exposure to the flu while limiting day-to-day interruption in schools,” Napolitano said.

The new head of the city’s Department of Health says if H1N1 remains mild it is unlikely school closures will be recommended. However, that could change if the virus becomes more severe and widespread.

As for children staying home, the Health Department recommends they stay out of school if they have symptoms, slightly different than the CDC guidelines.

The H1N1 virus has not disappeared during the warm, humid days of summer. And the question is how the virus will react this fall.

Speaking on CBS’s “The Early Show,” Education Secretary Arne Duncan said he would like schools to be used as vaccination sites once the vaccine is available in October.

Meanwhile, a French drugmaker says it began testing its H1N1 vaccine on about 2,000 people in the United States yesterday.

Sanofi Pasteur is testing the vaccine’s safety and how many doses would be needed. Most experts think two doses will be necessary.

The World Health Organization says the first batches of the vaccine should be delivered in September.

Pasteur has applied to the U.S. Food and Drug Administration for fast-track licensing for the vaccine.

(Source: NY1)