title: Mumps antibody levels among students before a mumps outbreak: in search of a correlate of immunity.
abstract: BACKGROUND
  In 2006, a mumps outbreak occurred on a university campus despite ≥ 95% coverage of students with 2 doses of measles-mumps-rubella (MMR) vaccine. Using plasma samples from a blood drive held on campus before identification of mumps cases, we compared vaccine-induced preoutbreak mumps antibody levels between individuals who developed mumps (case patients) and those who did not develop mumps (nonpatients).
  
  
  METHODS
  Preoutbreak samples were available from 11 case patients, 22 nonpatients who reported mumps exposure but no mumps symptoms, and 103 nonpatients who reported no known exposure and no symptoms. Antibody titers were measured by plaque reduction neutralization assay using Jeryl Lynn vaccine virus and the outbreak virus Iowa-G/USA-06 and by enzyme immunoassay (EIA).
  
  
  RESULTS
  Preoutbreak Jeryl Lynn virus neutralization titers were significantly lower among case patients than unexposed nonpatients (P = .023), and EIA results were significantly lower among case patients than exposed nonpatients (P = .007) and unexposed nonpatients (P = .009). Proportionately more case patients than exposed nonpatients had a preoutbreak anti-Jeryl Lynn titer < 31 (64% vs 27%, respectively; P = .065), an anti-Iowa-G/USA-06 titer < 8 (55% vs 14%; P = .033), and EIA index standard ratio < 1.40 (64% vs 9%; P = .002) and < 1.71 (73% vs 14%, P = .001).
  
  
  CONCLUSIONS
  Case patients generally had lower preoutbreak mumps antibody levels than nonpatients. However, titers overlapped and no cutoff points separated all mumps case patients from all nonpatients.
authors.affiliation: Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Atlanta, Georgia, USA. mcortese@cdc.gov
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Cortese
authors.forename: Albert E
authors.initials: AE
authors.lastname: Barskey
authors.forename: Gary E
authors.initials: GE
authors.lastname: Tegtmeier
authors.forename: Cheryl
authors.initials: C
authors.lastname: Zhang
authors.forename: Laurie
authors.initials: L
authors.lastname: Ngo
authors.forename: Moe H
authors.initials: MH
authors.lastname: Kyaw
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Baughman
authors.forename: Jay E
authors.initials: JE
authors.lastname: Menitove
authors.forename: Carole J
authors.initials: CJ
authors.lastname: Hickman
authors.forename: William J
authors.initials: WJ
authors.lastname: Bellini
authors.forename: Gustavo H
authors.initials: GH
authors.lastname: Dayan
authors.forename: Gail R
authors.initials: GR
authors.lastname: Hansen
authors.forename: Steven
authors.initials: S
authors.lastname: Rubin
mesh_terms: D000293:Adolescent; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood*; D015415:Biomarkers; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007484:Iowa / Q000453:epidemiology; D008297:Male; D022542:Measles-Mumps-Rubella Vaccine / Q000008:administration & dosage / Q000276:immunology; D009107:Mumps / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control*; D013334:Students; D010948:Viral Plaque Assay; D055815:Young Adult
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D015415:Biomarkers; D022542:Measles-Mumps-Rubella Vaccine