Paper Information

Vaccination is the primary strategy to reduce influenza burden. Influenza vaccine effectiveness (VE) can vary annually depending on circulating strains.

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.

Influenza vaccination decreased the risk of influenza-related pediatric hospitalizations by >50% across five influenza seasons.

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.