title: Mumps vaccine performance among university students during a mumps outbreak.
abstract: BACKGROUND
  The largest reported mumps outbreak at a US college in 19 years occurred in 2006 at a Kansas university with a 2-dose measles-mumps-rubella (MMR) vaccination policy. We assessed vaccine performance and mumps risk factors, including the possibility of waning vaccine protection.
  
  
  METHODS
  Case students were compared with a cohort of the university's approximately 19,000 undergraduates. The secondary attack rate for clinical mumps was determined among roommates exposed to case students. Time from receipt of the second dose of MMR vaccine was compared between case students and roommates without mumps.
  
  
  RESULTS
  Coverage with > or =2 dose of MMR vaccine was > or =95% among 140 undergraduate case students and 444 cohort students. The secondary attack rate for clinical mumps among roommates who had received 2 doses of vaccine ranged from 2.2% to 7.7%, depending on the case definition. Compared with roommates without mumps, case students were more likely (odds ratio, 2.46; 95% confidence interval, 1.25-4.82) to have received their second dose of MMR vaccine > or =10 years earlier. The odds of being a case student increased with each 1-year increase in time from receipt of the second dose of MMR vaccine (odds ratio, 1.36; 95% confidence interval, 1.10-1.68) among case students and roommates aged 18-19 years but not among those aged > or =20 years. Students aged 18-19 years had a higher risk of mumps (risk ratio, 3.14; 95% confidence interval, 1.60-6.16), compared with students aged > or =22 years; women living in dormitories had increased risk of mumps (risk ratio, 1.95; 95% confidence interval, 1.01-3.76), compared with men not living in dormitories.
  
  
  CONCLUSIONS
  High 2-dose MMR coverage protected many students from developing mumps but was not sufficient to prevent the mumps outbreak. Vaccine-induced protection may wane. Similar US settings where large numbers of young adults from wild-type naive cohorts live closely together may be at particular risk for mumps outbreaks.
authors.affiliation: National Center for Immunization and Respiratory Diseases, Office of Workforce and Career Development, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. mcortese@cdc.gov
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Cortese
authors.forename: Hannah T
authors.initials: HT
authors.lastname: Jordan
authors.forename: Aaron T
authors.initials: AT
authors.lastname: Curns
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Quinlan
authors.forename: Kim A
authors.initials: KA
authors.lastname: Ens
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Denning
authors.forename: Gustavo H
authors.initials: GH
authors.lastname: Dayan
mesh_terms: D015331:Cohort Studies; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007615:Kansas / Q000453:epidemiology; D008297:Male; D022542:Measles-Mumps-Rubella Vaccine / Q000008:administration & dosage / Q000276:immunology*; D009107:Mumps / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control; D009108:Mumps Vaccine / Q000008:administration & dosage / Q000276:immunology*; D013334:Students / Q000706:statistics & numerical data*; D014495:Universities
chemical_list: D022542:Measles-Mumps-Rubella Vaccine; D009108:Mumps Vaccine