title: Risk of hospitalization because of aseptic meningitis after measles-mumps-rubella vaccination in one- to two-year-old children: an analysis of the Vaccine Safety Datalink (VSD) Project.
abstract: OBJECTIVE
  To assess the level of increased risk, if any, of hospitalizations for aseptic meningitis after Jeryl-Lynn mumps strain measles-mumps-rubella (MMR) vaccine in the Vaccine Safety Datalink population.
  
  
  METHODS
  A possible increased risk of aseptic meningitis 8 to 14 days after receipt of MMR was observed in a preliminary screening analysis of automated data from the Vaccine Safety Datalink (VSD) project Year 2 analysis. To further evaluate this association a retrospective 10-year matched case-control study was undertaken in the four health maintenance organizations (HMOs) in the VSD project. Cases ascertained from a broad scan of the automated data were validated against a standard case definition. Two controls matched on age, sex, HMO and HMO membership were assigned per case.
  
  
  RESULTS
  The VSD project involves the cooperative collection of automated vaccination and medical outcome data from four large HMOs that currently have 500,000 children younger than 7 years of age under surveillance. Review of automated screening results from the first 2 years of data revealed a possible increased risk of aseptic meningitis 0 to 14 days after MMR with a relative risk of 3.61 (95% confidence interval, 1.0 to 13.1) although the total number of cases was small. Although the automated data had suggested a possible association of aseptic meningitis with MMR containing the Jeryl-Lynn strain of mumps, review of validated hospitalized cases during the observation period did not reveal evidence of an increased risk of aseptic meningitis after MMR containing the Jeryl-Lynn strain of mumps (odds ratio < 1.0 for all analyses).
  
  
  CONCLUSIONS
  Although it is recognized that hospitalized cases represent a minority of the total cases of aseptic meningitis, it is reassuring that in this evaluation no increased risk of aseptic meningitis after MMR vaccine was found.
authors.affiliation: Kaiser Permanente Vaccine Study Center, Oakland, CA, USA. steve.black@ncal.kaiperm.org
authors.forename: S
authors.initials: S
authors.lastname: Black
authors.forename: H
authors.initials: H
authors.lastname: Shinefield
authors.forename: P
authors.initials: P
authors.lastname: Ray
authors.forename: E
authors.initials: E
authors.lastname: Lewis
authors.forename: R
authors.initials: R
authors.lastname: Chen
authors.forename: J
authors.initials: J
authors.lastname: Glasser
authors.forename: S
authors.initials: S
authors.lastname: Hadler
authors.forename: J
authors.initials: J
authors.lastname: Hardy
authors.forename: P
authors.initials: P
authors.lastname: Rhodes
authors.forename: E
authors.initials: E
authors.lastname: Swint
authors.forename: R
authors.initials: R
authors.lastname: Davis
authors.forename: R
authors.initials: R
authors.lastname: Thompson
authors.forename: J
authors.initials: J
authors.lastname: Mullooly
authors.forename: M
authors.initials: M
authors.lastname: Marcy
authors.forename: C
authors.initials: C
authors.lastname: Vadheim
authors.forename: J
authors.initials: J
authors.lastname: Ward
authors.forename: S
authors.initials: S
authors.lastname: Rastogi
authors.forename: R
authors.initials: R
authors.lastname: Wise
mesh_terms: D016022:Case-Control Studies; D002675:Child, Preschool; D016001:Confidence Intervals; D005260:Female; D006279:Health Maintenance Organizations; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008458:Measles Vaccine / Q000009:adverse effects*; D022542:Measles-Mumps-Rubella Vaccine; D008582:Meningitis, Aseptic / Q000453:epidemiology* / Q000209:etiology*; D009108:Mumps Vaccine / Q000009:adverse effects*; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D012411:Rubella Vaccine / Q000009:adverse effects*; D013223:Statistics as Topic; D014481:United States / Q000453:epidemiology; D017778:Vaccines, Combined / Q000009:adverse effects
chemical_list: D008458:Measles Vaccine; D022542:Measles-Mumps-Rubella Vaccine; D009108:Mumps Vaccine; D012411:Rubella Vaccine; D017778:Vaccines, Combined