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Table 4 Vaccine effectiveness (VE) of TIV against influenza-related hospitalization in patients ≥16–64 years (younger adults group)

From: Influenza vaccine effectiveness against influenza-related hospitalization during a season with mixed outbreaks of four influenza viruses: a test-negative case-control study in adults in Canada

  Cases Controls Unadjusted Adjusted
  N N VE, % 95% CI VE, % 95% CI
All strains 208 271 35.8 4.5, 56.8 33.2a −6.7, 58.2
Influenza A 86 110 48.5 1.4, 73.1 42.2b −24.2, 73.1
 A/H1N1 55 68 57.8 2.7, 81.7 68.7c 6.4, 89.5
 A/H3N2 13 18 38.2 −599.5, 94.5
Influenza B 122 161 26.2 −22.2, 55.4 25.4d −35.4, 58.9
 B/Victoria 37 48 25.6 −82.8, 69.7 9.7e −161.6, 68.9
 B/Yamagata 53 70 16.6 −81.1, 61.6 36.9f −72.5, 76.9
  1. N number of patients, CI Confidence Interval, TIV trivalent influenza vaccine, VE vaccine effectiveness
  2. Covariate (p-value in model):
  3. a Influenza vaccination (0.092), age (0.018), anti-viral use before admission (0.881), seniors including patient living in dwelling (0.020), pregnancy (0.045);
  4. b Influenza vaccination (0.160), age (0.192), anti-viral use before admission (0.874) seniors including patient living in dwelling (0.188), pregnancy (0.991);
  5. c Influenza vaccination (0.038), age (0.173), anti-viral use before admission (0.895) seniors including patient living in dwelling (0.201), pregnancy (0.994);
  6. d Influenza vaccination (0.335), age (0.045), seniors including patient living in dwelling (0.046), pregnancy (0.099);
  7. e Influenza vaccination (0.850), age (0.054), seniors including patient living in dwelling (0.888), pregnancy (0.996);
  8. f Influenza vaccination (0.370), age (0.783), seniors including patient living in dwelling (0.037), pregnancy (0.740)