Countywide school-based influenza immunization: direct and indirect impact on student absenteeism.
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.
Davis
Mollie M
MM
Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland 21205, USA. mdavis93@jhmi.edu
King
James C
JC
Moag
Lauren
L
Cummings
Ginny
G
Magder
Laurence S
LS
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