Researchers have known that flu season traditionally occurs in winter, and from year to year they've had a pretty good idea of which strains will be dominant. But predicting the path of illness has been difficult. So researchers at Tufts University attempted to establish a pattern for flu outbreaks' timing and intensity.
They analyzed older adults' hospitalization records for the 1991 through 2004 flu seasons. (This means the new H1N1 strain was not part of the equation.) And they found that flu seasons typically peaked first in the Western states and later in Eastern states. Nevada, Utah and California led the way; Rhode Island, New Hampshire and Maine wrapped things up.
