Prospective Study of School-based Influenza Vaccination's Impact on School Populations

This prospective cohort study will evaluate rates of virologically confirmed influenza in children attending schools with and without school-based vaccination programs. Eight schools (4455 students) in two school districts matched for size, race/ethnicity, socioeconomic status, and location will serve as intervention and control schools. During influenza season defined by local surveillance data, nasal/throat swabs will be obtained for rapid influenza detection assays from all children with fever and respiratory symptoms identified by teachers for evaluation in the school nurse's office. Absent children will be offered testing at a central location within the schools' communities.Rates of confirmed influenza illness in vaccinated and non-vaccinated children will be compared between schools with and without vaccination programs. Rates of absenteeism also will be evaluated. The investigators hypothesize that in addition to lowering rates of influenza in vaccinated children, raising vaccination rates by 30-40% through school-based vaccination programs will decrease incidence of influenza in non-vaccinated children attending those schools compared to non-vaccinated children in schools with low vaccination rates.