(WEATHER CHANNEL) The flu season is officially underway, marking the earliest start to widespread flu outbreaks in more than 15 years.
While flu season doesn't have a set start and end date, health officials consider it to kick off when a significant number of doctor's office visits are related to flu-like illnesses for three weeks in a row, according to the Associated Press. That threshold has now been met.
Data from the U.S. Centers for Disease Control and Prevention shows that flu cases have risen steadily over the past few weeks and continue to increase.
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