title: Effectiveness of Early Measles, Mumps, and Rubella Vaccination Among 6-14-Month-Old Infants During an Epidemic in the Netherlands: An Observational Cohort Study.
abstract: Routinely, the first measles, mumps, and rubella (MMR) vaccine dose is given at 14 months of age in the Netherlands. However, during a measles epidemic in 2013-2014, MMR vaccination was also offered to 6-14-month-olds in municipalities with <90% MMR vaccination coverage. We studied the effectiveness of the early MMR vaccination schedule.
  
  
  
  Parents of all infants targeted for early MMR vaccination were asked to participate. When parent(s) suspected measles, their infant's saliva was tested for measles-specific antibodies. The vaccine effectiveness (VE) against laboratory-confirmed and self-reported measles was estimated using Cox regression, with VE calculated as 1 minus the hazard ratio.
  
  
  
  Three vaccinated and 10 unvaccinated laboratory-confirmed cases occurred over observation times of 106631 and 23769 days, respectively. The unadjusted VE against laboratory-confirmed measles was 94% (95% confidence interval [CI], 79%-98%). After adjustment for religion and sibling's vaccination status, the VE decreased to 71% (-72%-95%). For self-reported measles, the unadjusted and adjusted VE was 67% (40%-82%) and 43% (-12%-71%), respectively.
  
  
  
  Infants vaccinated between 6 and 14 months of age had a lower risk of measles than unvaccinated infants. However, part of the effect was caused by herd immunity, since vaccinated infants were more likely to be surrounded by other vaccinated individuals.
authors.affiliation: Epidemiology and Surveillance Unit and.
authors.forename: Tom
authors.initials: T
authors.lastname: Woudenberg
authors.affiliation: Epidemiology and Surveillance Unit and.
authors.forename: Nicoline A T
authors.initials: NAT
authors.lastname: van der Maas
authors.affiliation: Epidemiology and Surveillance Unit and.
authors.forename: Mirjam J
authors.initials: MJ
authors.lastname: Knol
authors.affiliation: Epidemiology and Surveillance Unit and.
authors.forename: Hester
authors.initials: H
authors.lastname: de Melker
authors.affiliation: Center for Infectious Diseases Research, Diagnostics, and Screening, National Institute for Public Health and the Environment, Bilthoven, the Netherlands.
authors.forename: Rob S
authors.initials: RS
authors.lastname: van Binnendijk
authors.affiliation: Epidemiology and Surveillance Unit and.
authors.forename: Susan J M
authors.initials: SJM
authors.lastname: Hahné
mesh_terms: D000914:Antibodies, Viral / Q000032:analysis; D005260:Female; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D008297:Male; D008457:Measles / Q000453:epidemiology* / Q000517:prevention & control*; D022542:Measles-Mumps-Rubella Vaccine / Q000627:therapeutic use*; D009107:Mumps / Q000517:prevention & control*; D009426:Netherlands / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012409:Rubella / Q000517:prevention & control*; D012463:Saliva / Q000276:immunology; D057566:Self Report; D014611:Vaccination / Q000706:statistics & numerical data*
chemical_list: D000914:Antibodies, Viral; D022542:Measles-Mumps-Rubella Vaccine
keywords: Measles; early MMR; infants; vaccination.; vaccine effectiveness