School-Based Influenza Vaccination: Health and Economic Impact of Maine's 2009 Influenza Vaccination Program.

<bold>Objective: </bold>To estimate the societal economic and health impacts of Maine's school-based influenza vaccination (SIV) program during the 2009 A(H1N1) influenza pandemic.<bold>Data Sources: </bold>Primary and secondary data covering the 2008-09 and 2009-10 influenza seasons.<bold>Study Design: </bold>We estimated weekly monovalent influenza vaccine uptake in Maine and 15 other states, using difference-in-difference-in-differences analysis to assess the program's impact on immunization among six age groups. We also developed a health and economic Markov microsimulation model and conducted Monte Carlo sensitivity analysis.<bold>Data Collection: </bold>We used national survey data to estimate the impact of the SIV program on vaccine coverage. We used primary data and published studies to develop the microsimulation model.<bold>Principal Findings: </bold>The program was associated with higher immunization among children and lower immunization among adults aged 18-49 years and 65 and older. The program prevented 4,600 influenza infections and generated $4.9 million in net economic benefits. Cost savings from lower adult vaccination accounted for 54 percent of the economic gain. Economic benefits were positive in 98 percent of Monte Carlo simulations.<bold>Conclusions: </bold>SIV may be a cost-beneficial approach to increase immunization during pandemics, but programs should be designed to prevent lower immunization among nontargeted groups. [ABSTRACT FROM AUTHOR]