After last year's mildest flu season on record, influenza has returned with a vengeance.

A "moderately severe outbreak" of "old-fashioned influenza" is filling emergency rooms across the region and the country.

According to Dr. William Schaffner, Chair of the Department of Preventative Medicine at Vanderbilt University, this year's influenza outbreak began on the East Coast in November and quickly spread westward.

The Philadelphia region, among other East Coast metropolitan areas, "is having a harder time" with the flu than many other parts of the country, Schaffner said in an interview with the Huffington Post.

At Lehigh Valley Hospital, medical officials opened a "flu tent" outside the emergency room to handle the overflow. 

"If you haven't been vaccinated, still get vaccinated," Schaffner said. "If you haven't gotten it, wash your hands and keep your distance from people who are coughing and sneezing. Instead of going to the movies, rent a movie and watch it at home."

Watch the video to learn more.

Montgomery County officials on Friday announced that they were increasing the hours of availability for free flu vaccinations at locations in Norristown, Pottstown, and Willow Grove.

“There has been an increase in influenza activity in all regions of the state, including Montgomery County,” said Josh Shapiro, chair of the Montgomery County Commissioners.

“More than 7,000 flu cases were reported in Pennsylvania during the last two weeks of December 2012. Because the flu does not typically peak until mid-January or February, now is the time to get vaccinated. It is not too late,” Shapiro said in a statement issued by the county.

As of Wednesday, at least 22 people in Pennsylvania had died of causes related to this season's influenza outbreak.

The updated Montgomery County flu vaccine hours and locations are as follows:

Norristown Health Center

1430 DeKalb Street, Norristown, PA 19404

610-278-5145

Mondays— children under 19 years old by appointment only (times vary), please call for an appointment

Tuesdays-Fridays— all ages on a walk-in basis from 9:00am-3:00pm

Pottstown Health Center

364 King Street, Pottstown, PA 19464

610-970-5040

Mondays & Thursdays— all ages on a walk-in basis from 9:00am-3:00pm

Wednesdays—children under 19 years old by appointment only (times vary), please call for an appointment

Willow Grove Eastern Courthouse Annex

102 York Road, Suite 401, Willow Grove, PA 19090

215-784-5415

Thursdays— all ages by appointment from 9:00am-12:30pm, please call for an appointment and on a walk-in basis from 2:00pm-3:30pm on 1/17, 1/24 & 1/31