Crews are cleaning three public schools closed Tuesday due to swine flu, and a private school that planned to stay closed until next week has re-evaluated that decision after federal officials said schools don't need to close in response to confirmed cases of flu.

Oak Hill School planned to remain closed through May 11. In light of a new recommendation by the Centers for Disease Control, the school plans to resume classes on Wednesday, May 6.

Cleaning crews went through Kelly Middle School, the French Immersion School and Harris/Eastside Elementary Tuesday. The Eugene School District announced Tuesday that the schools will re-open on Wednesday.

On Monday, the CDC advised schools that have had confirmed cases of swine flu should close for up to two weeks. The CDC now says schools do not need to close after a confirmed case.

"We no longer feel that school closure is warranted," said Dr. Richard Besser, acting director of the Centers for Disease Control and Prevention.

Health and Human Services Secretary Kathleen Sebelius said the swine flu virus had turned out to be milder than feared and the government decided to change its advice. So far, the virus has not proved to be more infectious or deadly than the seasonal flu.

The CDC said parents should still make sure to keep sick children with flulike symptoms at home for seven days.

As the threat seemed to diminish, health officials also considered the problems the closings were creating for parents, Besser said. Officials were hearing about children getting dropped off at libraries, or parents who couldn't take sick leave to care for their children.

"The downsides of school closure start to outweigh the benefits," Besser said.

The change in guidance was made in consultation with the White House and other officials, Besser and others said.

An estimated 726 public and nonpublic schools were closed Tuesday for flu-related reasons, in 24 states and the District of Columbia, according to the Education Department. In total, these schools enroll approximately 468,000 students on a typical day. (There are more than 100,000 schools in the U.S., with about 55 million students.)

The number of confirmed swine flu cases in the United States is now over 400, with hundreds more probable cases. The CDC knows of 35 swine flu-related hospitalizations and one death, a Mexican toddler who died in Texas.

Nearly two of every three cases are under the age of 18, CDC officials said.

Local school officials still have the ultimate say in whether to close or not, CDC officials noted.

In the new guidance, the CDC recommends that when children or school staff are sick, they stay home. Those who do go to school should practice good hygiene — like coughing into their sleeve or shoulder instead of their hands or the air, and washing their hands well and often.