CHICAGO (CBS)—Mumps cases keep popping up at college campuses across the Chicago area, and even at a local high school.

Students at Lewis University started hearing about mumps warnings last week, but the word ‘outbreak’ started being used a few days ago after several possible cases came up. University officials have since started requiring students to show proof of vaccinations.

Lewis University announced Wednesday the decision to provide an immunization pop-up clinic on campus for students and staff to receive the MMR booster.

The pop-up clinics will be available De. 6 and Dec 7 in the University Dining Room.

Student Jerome Tolentino said he’s tried to stay away from other sick students.

“I’m definitely keeping away,” Tolentino said.

Cases have also been reported at Columbia College and Loyola University.

mumps cases Mumps Cases Reported At Chicago Area Campuses Just In Time For Finals Week

Dr. Laura McIntrye of Northwestern Medicine says the disease is transmitted though saliva, including coughing, sneezing or sharing utensils.

“(College campuses) are very easy place for mumps to spread because people are so close to each other,” McIntyre said.

The best way to prevent it from spreading is by making sure you’re properly immunized, she said.

“For people who have been vaccinated, they’re a lot less likely to get mumps,” she said. “Almost every case we see is with people who are unvaccinated.”

Next week students who don’t show evidence of immunity to the mumps will be restricted from Lewis University.

A Lewis University spokesperson said the university is working with public health officials to make sure high-traffic areas are sanitized and that the campus stays healthy.