Gallup: U.S. flu season lasting longer

WASHINGTON, May 6 (UPI) -- The U.S. flu season started slow last fall in September, October, and November, but extended longer into spring this year, a Gallup poll indicates.

The Gallup-Healthways Well-Being Index data measures the self-reports of colds and flu from 1,000 U.S. adults daily. Measuring cold versus flu is complex because of the overlapping symptoms and many Americans' misunderstanding what symptoms constitute "the flu" versus "a cold." The poll provides a picture of cold and flu prevalence trends.

Influenza peaked at 3.3 percent in February, higher than the 2.2 percent in February last year, with 2.1 percent reporting flu last April compared to 1.5 percent in April 2010.

Nearly 6 percent of American adults reported having a cold in April this year, versus 4.7 percent last April.

People living in the states of Alaska, West Virginia and Vermont were the most likely to report daily colds and flu this season, with some 13 percent of residents in each state reporting illness on any given day, while 7.4 percent of Nevadans reported either of these conditions on average each day -- the lowest in the nation.

Overall, the margin of error is 0.6 percentage point. For large states, the margin of error is 1 percentage point to 2 percentage points while small states have a margin of error as high as 4 percentage points.