Bay Area health officials reacted quickly.
"No schools will be closed and any schools closed currently will re-open tomorrow," said Dr. Marty Fenstersheib from the Santa Clara County Health Office.
All 15 schools in the Bay Area that were closed will reopen right away.
Federal officials now say this particular strain of the H1N1 virus does not seem to be as severe as they once thought it could be.
"So there is new guidance being out as we speak, that will recommend that schools stop closing the school itself with affected cases," said Health and Human Services Secretary Kathleen Sebelius.
Shortly after, some city and county health departments began giving schools the green light to reopen.
Berkeley Unified School District announced students from Malcolm X Elementary School should report to classes on Wednesday after being away for two days.
"I'm sure it is a big relief for a lot of our families to be able to come back to school tomorrow. I think they anticipated a whole week of being out, but this is good news," said Malcolm X Elementary School Principal Cheryl Chinn.
The school principal wasted no time sending e-mails. Parents were expected to get an automated phone call by the end of the day.
All five schools closed in contra Costa County also got clearance to reopen.
"One to three cases is not sufficient to close an entire school. The further we get into it, the more we realize that this is acting more like a mild seasonal flu virus," said Contra Costa County Health Officer Dr. William Walker.
In Santa Clara County, Daves Avenue Elementary School in Monte Sereno will allow students to come back after being away for only one day.
Mark Coplan of the Berkeley Unified School District says at the time, closing schools was the right thing to do.
"At this point they have enough information that they know where they are and they made that decision nationally on a pretty sound basis, but up until this point they took the very best precaution," said Coplan.
While most schools are preparing for classes to resume, principals are urging students to stay home if they're still sick.
All the schools that had to close will receive their average daily attendance money from the state. That's the money they receive per pupil, per day, so this should not turn into a budget issue.