title: Countywide school-based influenza immunization: direct and indirect impact on student absenteeism.
abstract: OBJECTIVE
  Live attenuated influenza vaccine was given to 5319 (44%) of the 12090 students enrolled in public elementary schools in Carroll County, Maryland, during the fall of 2005. We examined the impact of this community-based intervention on countywide student absenteeism during the subsequent influenza outbreak.
  
  
  METHODS
  This study used existing, anonymous information: census data, community influenza tests, and public school absenteeism data. The intervention group was Carroll County, years 2005-2006. The control group included Carroll County, years 2001-2005, and adjacent Frederick County, years 2001-2006. Weekly student absenteeism was determined during baseline influenza-free periods and influenza outbreak periods for all of the public schools.
  
  
  RESULTS
  The absolute change in absenteeism during the influenza outbreak periods over baseline in elementary schools was 0.61% for the intervention group and 1.79% for the control group. Similarly, the change in absenteeism during the influenza outbreak period over baseline for high schools was 0.32% for the intervention group and 1.80% for the control group. Although not statistically significant, trends in middle schools were similar.
  
  
  CONCLUSIONS
  Countywide school-based influenza vaccination was associated with reduced absenteeism during an influenza outbreak. The data suggest not only a direct impact on elementary schools but also an indirect impact on high schools. School-based programs provide an efficient method of providing influenza vaccination to children, and protection may extend to unvaccinated community members. Additional research is needed to determine whether school-based vaccination of children reduces morbidity and mortality associated with influenza outbreaks.
authors.affiliation: Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland 21205, USA. mdavis93@jhmi.edu
authors.forename: Mollie M
authors.initials: MM
authors.lastname: Davis
authors.forename: James C
authors.initials: JC
authors.lastname: King
authors.forename: Lauren
authors.initials: L
authors.lastname: Moag
authors.forename: Ginny
authors.initials: G
authors.lastname: Cummings
authors.forename: Laurence S
authors.initials: LS
authors.lastname: Magder
mesh_terms: D000041:Absenteeism; D000293:Adolescent; D002648:Child; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D017589:Immunization Programs; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D008396:Maryland / Q000453:epidemiology; D012572:School Health Services / Q000706:statistics & numerical data