Don't let down your guard. Keep washing your hands and coughing into your sleeve and keeping your distance from those who appear ill. But go ahead and exhale.

While it will take weeks, or maybe longer, for the H1N1 swine flu to run its course, the worst is over. By "worst," we mean the fear that gripped many Americans when it appeared that a potentially deadly strain of the virus would sweep the nation.

The national Centers for Disease Control and Prevention has toned down the alarm after it became apparent that the virus in its current form would be no more deadly in the U.S. than typical seasonal influenzas.

CDC experts are still working feverishly to develop a vaccine, which should be formulated in about two weeks and would be mass-produced and distributed if more severe cases surface. And they warn against complacency, and advise those exhibiting symptoms to stay home. But schools that the CDC ordered closed at the first sign of illness have been allowed to reopen.

A mild form of the virus is still spreading, with more than 1,100 confirmed or probable cases reported in at least 44 states, and two deaths attributed to the flu in Texas.

In Utah, where schools in Park City and the Salt Lake Valley have reopened, eight cases of swine flu have been confirmed and the results on 30 other cases are pending. But, thankfully, it appears we'll be spared the worst of the flu.

Consider it practice, a pandemic drill, and a highly successful one. The CDC responded quickly, coordinating containment efforts with world and state public health authorities, developing a vaccine, distributing anti-viral medication to state and local health departments, and providing states with kits to conduct their own testing.

Locally, schools where suspected cases were discovered were quick to close and slow to open, taking prudent and appropriate steps to prevent the spread of the virus.

In other schools, careful screening was conducted to keep sick kids and staff at home, and isolation rooms were promptly prepared in the event of sudden illness. Plus, students got a crash course in cough etiquette and hand hygiene, lessons that will serve them well and should be repeated often.

The possibility exists that the flu will return in the fall or winter, and if it mutates into a more virulent strain, it could return with a vengeance. Hopefully, that won't happen. But if it does, you can rest assured we'll be ready. We've already been through the drill.