As summer fades and leaves begin to change colors, students might begin to feel the chill of more than just falling temperatures, as flu season is right around the corner.

Students can take their first step in preventing the flu by getting a free flu shot from University Health Services and clinics around campus throughout the month of October, UHS epidemiologist Craig Roberts said.

Free cookies AND hand sanitizer bottles? Stop by our first flu shot clinic this Friday to get yours! #ImmunityBoost pic.twitter.com/fpYRM53MlY

— UHS UW-Madison (@UHSMadison) September 23, 2015

Typically each year, between 12,000 to 13,000 students receive a flu shot. Last year about13,500 students received a flu shot, Roberts said.

Although it’s difficult to determine exactly how many students were sick with the flu last year, UHS diagnoses an average of 600 to 700 cases of the flu each year, and last year diagnosed 621 students, Roberts said.

The flu vaccination varied in effectiveness each year, Roberts said. The effectiveness of the vaccine always depends on what flu strains are circulating and how the vaccine is made.

A flu virus may change and mutate each season, infectious disease associate professor Nasia Safdar said. The vaccine may be effective if the virus from the previous year does not change as much.

“[We] cannot predict what this year’s will look like until flu starts circulating, but any kind of vaccine for the flu is more efficacious than no vaccine against it,” Safdar said.

Last year the flu vaccine was almost ineffective because the predominate flu strain was not included in the vaccine, making the shot only about 20 percent effective, Roberts said.

But there are some other factors to include when considering the effectiveness of the vaccine.

“For younger people the vaccines work a lot better,” Roberts said. “For college students, usually it’s probably 50 to 60 percent effective in reducing the chances of the influenza illness.”

This year, Roberts said the vaccine has been modified to include the type of influenza that circulated last year, and the vaccination is expected to more effective.

Other preventative measures students can take to combat the flu include avoiding exposures to those who are sick and making sure to wash hands frequently because viruses may easily be picked up from objects that are touched, Roberts said.

UHS has four outreach clinics that will provide free flu shots through the end of October.

The first clinic opens at the Serf Sept. 25. UHS will also accept walk-ins.

After early November, students will need to make an appointment to receive their flu shot.