Updated

Loyola University says more than a dozen students have come down with mumps or suspected mumps cases.

University officials say the cases began in mid-February, and they are advising students on ways to avoid spreading the virus. The university says affected students live on and off campus, and the Baltimore city and Maryland health departments are investigating possible links among the students.Baltimore’s health department says 12 of the cases have been confirmed. The federal Centers for Disease Control says mumps was once common but has become rare because most are now vaccinated against the disease. Loyola says vaccination for the disease is required for enrollment in the university.

Assistant Health Commissioner Patrick Chaulk says the mumps vaccine is about 90 percent effective, and outbreaks most often occur at universities.