Caroline Brown, a sophomore at the University of Missouri, got a fever over Thanksgiving break. Soon it became painful to bite down, and her cheek began to swell. A trip to her physician confirmed it: she had the mumps.
"Mumps kind of sounds like this archaic thing," Brown said. "We get vaccinated for it; it just sounds like something that nobody gets. So I just didn't think that it was possible that I would get it."
But mumps is back, and is having its worst year in a decade, fueled in part by its spread on college campuses. Since classes began at the University of Missouri in August, school officials have identified 193 mumps cases on campus. Nationwide, more than 4,000 cases have been reported to the Centers for Disease Control and Prevention - nearly triple the number in 2015 and the largest increase in 10 years.
Some public health officials are asking questions about the vaccine protocol.
Dr. Susan Even, executive director of the University of Missouri's Student Health Center, said she hasn't seen anything like the current outbreak in her 31 years at the school. She said all of the students her team treated for mumps had two MMR (Measles, Mumps and Rubella) vaccine doses - a school requirement - but they got sick anyway.
"The fact that we have mumps showing up in highly immunized populations likely reflects something about the effectiveness of the vaccine," Even said.
Outbreaks are affecting several other universities..