CHICAGO (CBS) — Hundreds of students at Northern Illinois University have received booster shots, as the university tries to keep a mumps outbreak under control.

The university has confirmed 10 cases of mumps, most recently on Friday.

“So far, all the confirmed cases are among athletes”, according to NIU spokesman Joe King.

To his knowledge, all the students who came down with mumps had been inoculated as children.

More than 650 student-athletes and the people they come in contact with most — girlfriends, boyfriends, and roommates, etc. — were given booster shots. They’ve also been told to watch for symptoms of mumps; which include swollen glands under one or both ears, fever, headaches, muscle aches, fatigue, and loss of appetite.

King said ways to help prevent the spread of mumps include good handwashing, coughing into your arm, and not rubbing your eyes. He also pointed out mumps has been going around elsewhere in Illinois, with a big outbreak earlier in the year at the University of Illinois at Urbana-Champaign, and with some cases at Illinois State University and Quincy College.