A Retrospective Test-Negative Case-Control Study to Evaluate Influenza Vaccine Effectiveness in Preventing Hospitalizations in Children

Abstract

Background Vaccination is the primary strategy to reduce influenza burden. Influenza vaccine effectiveness (VE) can vary annually depending on circulating strains. Methods We used a test-negative case-control study design to estimate influenza VE against laboratory-confirmed influenza-related hospitalizations among children (6 months-17 years) across 5 influenza seasons in Atlanta, Georgia from 2012-13 to 2016-17.Influenza-positive cases were randomly matched to test-negative controls based on age and influenza season in a 1:1 ratio. We used logistic regression models to compare odds ratios (OR) of vaccination in cases to controls. We calculated VE as [100% x (1-adjusted OR)] and computed 95% confidence intervals (CIs) around the estimates. Results We identified 14,596 hospitalizations of children who were tested for influenza using multiplex respiratory molecular panel; influenza infection was detected in 1,017 (7.0%). After exclusions, we included 512 influenza-positive cases and 512 influenza-negative controls; median age was 5.9 years (IQR 2.7-10.3); 497 (48.5%) were female, 567 (55.4%) were non-Hispanic Black and 654 (63.9%) children were unvaccinated. Influenza A accounted for 370 (72.3%) of 512 cases and predominated during all five seasons. The adjusted VE against influenza-related hospitalizations during 2012-13 to 2016-17 was 51.3% (95% CI 34.8-63.6%) and varied by season. Influenza VE was 54.7% (95% CI 37.4-67.3%) for influenza A and 37.1% (95% CI 2.3–59.5%) for influenza B. Conclusions Influenza vaccination decreased the risk of influenza-related pediatric hospitalizations by >50% across five influenza seasons.

Resurgence of influenza during COVID‐19 in Chongqing, China: A retrospective analysis

“…33 The effectiveness of influenza vaccination in preventing hospitalization and influenza-related death in children was supported by a robust body of evidence. [34][35][36] Influenza vaccination of school-aged children benefits the children themselves, as well as helps reduce community-level influenza transmission, whereas the early influenza vaccination rates in children declined in a year with a concurrent COVID-19 pandemic. 37,38 Thus, it is essential to prioritize influenza vaccination (cell-culture-derived quadrivalent inactivated influenza vaccine (IIV4c) was prioritized 39 ) and implement comprehensive interventions to mitigate the impact of influenza.…”

“…All children over 6 months old without medical contraindications were recommended annual influenza vaccination, following the American Academy of Pediatrics’ advice 33 . The effectiveness of influenza vaccination in preventing hospitalization and influenza‐related death in children was supported by a robust body of evidence 34–36 . Influenza vaccination of school‐aged children benefits the children themselves, as well as helps reduce community‐level influenza transmission, whereas the early influenza vaccination rates in children declined in a year with a concurrent COVID‐19 pandemic 37,38 .…”

The clinical predictors of and vaccine protection against severe influenza infection in children

“…Influenza vaccine offered significant protection against laboratory‐confirmed influenza‐related hospitalizations. The vaccine effectiveness was over 50% among children across five influenza seasons from 2012–2013 to 2016–2017 7 . The coadministration of pneumococcal conjugate vaccines (PCVs) with influenza vaccines may provide additional benefits.…”

“…The vaccine effectiveness was over 50% among children across five influenza seasons from 2012-2013 to 2016-2017. 7 The coadministration of pneumococcal conjugate vaccines (PCVs) with influenza vaccines may provide additional benefits. Streptococcus pneumoniae is one of the leading causes of secondary bacterial pneumonia after influenza infection.…”

COVID-19 vaccine effectiveness studies in Nigeria: Quo vadis?

“…), time since vaccination, and viral strain. The TNCC study design is commonly used in estimating the VE of Influenza vaccines, and it is now being increasingly used in COVID-19 VE studies [2][3][4][5][6].…”