Impact of a school-based influenza immunization program on disease burden: Comparison of two Tennessee counties

Departments of Pediatrics and Epidemiology and Prevention, Wake Forest University School of Medicine, Winston-Salem, NC, United States.
Vaccine (Impact Factor: 3.62). 06/2009; 27(20):2695-700. DOI: 10.1016/j.vaccine.2009.02.043
Source: PubMed


Outpatient burden of laboratory-confirmed influenza among children in Knox and Davidson Counties was compared in 2006-2007 when only Knox County had a school-based influenza vaccine campaign. Of 1016 eligible children seeking outpatient care, 87% were enrolled and 20% were influenza-positive. Estimated influenza vaccination coverage was similar in Knox and Davidson for preschool-age children (36% versus 33%) but higher in Knox County for school-age children (44% versus 12%). Influenza detection was higher among Knox than Davidson County preschool-age children (18% versus 10%) but similar among school-age children (28% versus 27%). These data are consistent with a direct effect of the campaign in school-age children.

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Available from: Yuwei Zhu, Nov 10, 2014
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    • "School children drive influenza epidemics through virus transmission to their contacts1234. Mathematical models and field research suggest that vaccinating school children provides indirect protection (herd immunity) to both household members and the community at large56789, thereby reducing the burden of influenza. However, influenza vaccine coverage in children is suboptimal for various reasons, including accessibility, competing demands, and fear of needles among children[. "
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    ABSTRACT: Children are key drivers of influenza transmission. Vaccinating school age children decreases influenza in the community. To pilot-test the methods for a future trial to compare the direct and indirect benefits of inactivated influenza vaccine (IIV) vs. live attenuated influenza vaccine (LAIV) in preventing influenza infection. During the 2013-14 influenza vaccination campaign, we piloted an open-label cluster randomized trial involving 10 elementary schools in Peterborough, Ontario, Canada. We randomized schools on a 1:1 basis to have students receive IIV or LAIV. We invited a subset of vaccinated students and their households to participate in a surveillance sub-study, which involved completing daily symptom diaries during influenza season and collecting mid-turbinate swabs from symptomatic individuals to detect influenza infection. The main outcome measure confirmed influenza infection using a real-time reverse transcriptase polymerase chain reaction (PCR) assay. One hundred and nineteen households (166 students and 293 household members) participated. During 15 weeks of surveillance, we detected 22 episodes of PCR-confirmed influenza (21 influenza A/H1N1 and 1 influenza B). The incidence of influenza per 1000 person-days was 1.24 (95% CI, 0.40-2.89) for IIV-vaccinated students, compared to 0.13 (95% CI, 0.003-0.72) for LAIV-vaccinated students; the incidence rate ratio was 0.10 (95% CI, 0.002-0.94). Similarly, the incidence of influenza per 1000 person-days was 1.33 (95% CI, 0.64-2.44) for IIV household members, compared to 0.47 (95% CI, 0.17-1.03) for LAIV household members; the incidence rate ratio was 0.36 (95% CI, 0.11-1.08). The overall incidence rate ratio (combining students and household members) was 0.27 (95% CI, 0.09-0.69). Household surveillance involving participant monitoring and reporting of symptoms and self-collection of mid-turbinate swabs is feasible. A larger study is required to validate the suggestion that vaccinating children with LAIV might confer more protection against influenza for both children and their household contacts, compared to IIV. NCT01995851. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
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    • "This was for the direct benefit to the immunized child which has been demonstrated in several studies. Immunization of children enrolled in day-care centers [6] and schools [7] [8] [9] has been found to reduce illness, absenteeism, medical care and OTC medication use in the families of both immunized and unimmunized students. Modeling has suggested that vaccinating school children could reduce the spread of pandemic influenza with as low a coverage rate as 20% [10]. "
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    ABSTRACT: Models predict that immunizing as few as 20% of school children, important transmitters of influenza, will reduce influenza-related illness in the elderly. We evaluated the potential herd immunity during three influenza seasons, 2005-2006, 2006-2007 and 2007-2008, which followed the immunization of>40% of school children in Knox County (KC), TN, with live, attenuated influenza vaccine. Individual-level demographic, health status and health service utilization information about KC residents>65 years and those residing in the 8 surrounding counties was obtained from the United States Medicare Program's administrative data. Influenza seasons were identified based on virus isolation. Pneumonia and influenza (P&I) hospitalization rates per 1,000 were compared between the elderly residing in the two areas for the three influenza seasons, and the 3 prior seasons. Differences-in-difference multivariate analysis allowed us to estimate the effect of the school-based immunization program on P&I hospitalization rates simultaneously adjusting for other important individual-level covariates. The age-adjusted rates among the KC residents were significantly lower, 4.62 and 6.02 versus 6.54 and 7.58 than in the residents of the comparison counties during the first two intervention seasons, p=0.001 and 0.037, respectively, but not in the third. However, after adjusting for the traditionally lower rates of P&I hospitalization in the comparison counties, as well as for the other covariates, we were not able to demonstrate a statistically significant effect of the vaccination program in reducing the rates in either group of the elderly. The impact of the covariates was as expected. Those associated with increased P&I hospitalization rates were increasing age, lower income, poorer health status, prior hospitalization (particularly for P&I), and high prior use of physician services. Influenza immunization of an elderly person reduced his/her probability of being hospitalized for P&I. In conclusion, Immunization of>40% of school children did not result in a reduction of P&I hospitalization rates among the elderly. We believe that the failure to show an impact was likely due to the high level of immunization among the elderly (> 60%). Administration of influenza vaccine to children as a way to protect the elderly in situations where vaccine supplies are limited or the elderly are not accustomed to receiving influenza vaccine may still be appropriate.
    Preview · Article · Dec 2011 · Procedia in Vaccinology
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    ABSTRACT: This work describes the development of a tool that predicts the coverage and performance of sensor networks. Specifically it examines weapon locating radars and acoustic sensors in different terrain and weather conditions. The computer environment and multiple sensor models are presented. Fusion of sensors takes multiple predicted accuracy metrics from the single sensor performance models and combines them to show networked performance. Calculations include Cramer-Rao lower bound computation of the sensors and the fused sensors' source location error. Results are presented showing the outputs of the models in the form of sensor accuracy maps superimposed onto terrain maps and early conclusions assessing feasibility of model reduction to simple algorithms are given.
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