Cities should close schools for up to three months in the event of a severe flu outbreak, ball games and movies should be canceled ... the federal government advised today in issuing new pandemic flu guidelines to states and cities. Health officials acknowledged that such measures would hugely disrupt public life, but they argued that these measure would buy the time needed to produce vaccines and would save lives. We have to be prepared for a Category 5 pandemic," said Dr. Martin Cetron, director of global migration and quarantine for the Centers for Disease Control and Prevention. "It's not easy. The only thing that's harder is facing the consequences." The new guidelines also advocate having sick people and all their families' even apparently healthy members stay home for 7 to 10 days. Any pandemic is expected to move faster than a new vaccine can be produced. Current experimental vaccines against H5N1 avian flu are in short supply and based on strains isolated in 2004 or 2005. Although the government is creating a $4 billion stockpile of the antiviral drug Tamiflu, it is only useful when taken within the first 48 hours, and Tamiflu-resistant flu strains have already been found. The historian John Barry, author of "The Great Influenza," a history of the 1918 flu, questioned an idea underpinning the study's conclusions. There is evidence, he said, that some cities with low sickness and death rates in 1918 ... were hit by a milder spring wave of the virus. That would have, in effect, inoculated their citizens against the more severe fall wave and might have been more important than their public health measures.