Symptoms of the flu don't only include a high fever, weak muscles and a sore throat. The ramifications spread to the workplace, schools, family and other segments of people's everyday lives, according to the 2013 Flu Impact Report from Walgreens.

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The report describes last flu season (2012-13) as one of the most severe in the U.S. in over a decade. The number of people who missed vacation time nearly tripled, while students missed 91 million days of school and employees lost out on 230 million days of work.

In 2010-11, according to the report, 20 percent of respondents suffered from the flu. Last season, the percentage jumped to 46.

"The flu hit early last year," said Dr. Harry Leider, Chief Medical Officer of Walgreens. "It peaked in December, so lots of people weren't vaccinated and they got the flu."

Dr. Leider said a large number of people panicked and received their vaccinations in January, but they missed out on the maximum opportunity for protection.

"This is the time to get (a shot)," Leider continued. "There's no reason to wait."

He noted it generally takes someone two weeks to build immunity after a shot, and that's why acting early is the smarter route.

The flu season is always unpredictable, the report stated. Health experts can't tell at this point whether the 2013-14 season will be mild or severe.