Learning Objectives for this Presentation:
By the end of the presentation, participants will be able to:
1. Describe mumps
2. Discuss the University of Kansas mumps outbreak
3. Understand the importance of vaccination


Background:
Mumps is the only known cause of epidemic parotitis. Incidence has declined by >99% since the live-attenuated vaccine was licensed in 1967. In April 2006, the University of Kansas reported the first mumps outbreak in Kansas since 1989. This school has had a two-dose measles-mumps-rubella (MMR) vaccination requirement since 1992. By May 8, 2006, 173 cases were reported among 25,379 students.

Objectives:
We conducted a case-control study to identify risk factors associated with disease.

Methods:
We interviewed cases and controls. A case was defined as an undergraduate student with disease onset during January 1 to May 8, 2006, who had parotitis for two or more days, males with orchitis, or identification of mumps virus from a clinical specimen. Controls were randomly selected from undergraduate students and denied mumps symptoms upon interview.

Results:
For the 97 cases and 147 controls, 96% had complete immunization records. Of these, 99% of the cases and 99% of the controls had at least two doses of MMR vaccine. By univariate analysis, cases were more likely to be freshman (34% of the cases; odds ratio [OR]=3.2; 95% confidence interval [CI]=1.7-6.4), report exposure to mumps (33%; OR=2.8; 95% CI=1.4-5.5), live in a dormitory (26%; OR=2.1; 95% CI=1.0-4.2), and be female (62%; OR=2.0; 95% CI=1.2-3.6). Factors not associated with disease included traveling, sharing a bedroom, eating or working on campus.

Conclusions:
A mumps outbreak occurred in a highly vaccinated university population. Congregate settings may have increased risk for such outbreaks. Known exposure to mumps was associated with disease. Living in dormitories, being female or freshman were also risk factors. These characteristics may be associated with increased likelihood or increased intensity of mumps exposure.