C.H. Tran, J.D. Sugimoto, J.R.C. Pulliam, K.A. Ryan, P.D. Myers,
J.B. Castleman, R. Doty, J. Johnson, J. Stringfellow,
N. Kovacevich, J. Brew, L.L. Cheung, B. Caron, G. Lipori,
C.A. Harle, C. Alexander, Y. Yang, I.M. Longini Jr.,
M.E. Halloran, J.G. Morris Jr., P.A. Small Jr.
PLOS ONE
December 9, 2014
Background
School-located influenza vaccination (SLIV) programs can substantially enhance the sub-optimal coverage achieved under existing delivery strategies. Randomized SLIV trials have shown these programs reduce laboratory-confirmed influenza among both vaccinated and unvaccinated children. This work explores the effectiveness of a SLIV program in reducing the community risk of influenza and influenza-like illness (ILI) associated emergency care visits.
Methods
For the 2011/12 and 2012/13 influenza seasons, we estimated age-group specific attack rates (AR) for ILI from routine surveillance and census data. Age-group specific SLIV program effectiveness was estimated as one minus the AR ratio for Alachua County versus two comparison regions: the 12 county region surrounding Alachua County, and all non-Alachua counties in Florida.
Results
Vaccination of ~50% of 5–17 year-olds in Alachua reduced their risk of ILI-associated visits, compared to the rest of Florida, by 79% (95% confidence interval: 70, 85) in 2011/12 and 71% (63, 77) in 2012/13. The greatest indirect effectiveness was observed among 0–4 year-olds, reducing AR by 89% (84, 93) in 2011/12 and 84% (79, 88) in 2012/13. Among all non-school age residents, the estimated indirect effectiveness was 60% (54, 65) and 36% (31, 41) for 2011/12 and 2012/13. The overall effectiveness among all age-groups was 65% (61, 70) and 46% (42, 50) for 2011/12 and 2012/13.
Conclusion
Wider implementation of SLIV programs can significantly reduce the influenza-associated public health burden in communities.