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Table 3 Vaccine effectiveness (VE) of TIV against influenza-related hospitalization in patients ≥16 years (all 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 528 835 41.8 26.0, 54.3 42.8a 23.8, 57.0
Influenza A 182 301 50.4 23.9, 67.6 55.6b 23.4, 74.3
A/H1N1 89 142 71.7 41.7, 86.3 72.5c 30.5, 89.1
A/H3N2 56 105 31.0 −45.9, 67.5 86.1d 40.1, 96.8
Influenza B 346 534 37.3 16.0, 53.2 36.2e 10.0, 54.7
B/Victoria 81 126 47.1 3.4, 71.0 40.5f −28.9, 72.6
B/Yamagata 188 292 28.7 −5.4, 51.8 32.3g −8.3, 57.7
  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 (<0.001), age (0.378), anti-viral use before admission (0.902), admission from long term care facility (0.005), obesity (0.119), exposed to children aged <5 years in household (0.034), current or past smoker (0.000), medications before onset of illness (0.011);
  4. b Influenza vaccination (0.004), age (0.264), anti-viral use before admission (0.766), admission from long term care facility (0.592), obesity (0.633), exposed to children aged <5 years in household (0.157), current or past smoker (0.376), medications before onset of illness (0.191);
  5. c Influenza vaccination (0.006), age (0.093), anti-viral use before admission (0.814), admission from long term care facility (0.993), obesity (0.199), exposed to children aged <5 years in household (0.311), current or past smoker (0.188), medications before onset of illness (0.046);
  6. d Influenza vaccination (0.008), age (0.022), admission from long term care facility (0.419), obesity (0.998), exposed to children aged <5 years in household (0.046), current or past smoker (0.571), medications before onset of illness (0.560);
  7. e Influenza vaccination (0.010), age (0.791), anti-viral use before admission (0.471), admission from long term care facility (0.001), obesity (0.143), exposed to children aged <5 years in household (0.096), current or past smoker (0.000), medications before onset of illness (0.023);
  8. f Influenza vaccination (0.188), age (0.215), admission from long term care facility (0.794), obesity (0.750), exposed to children aged <5 years in household (0.184), current or past smoker (0.025), medications before onset of illness (0.093);
  9. g Influenza vaccination (0.103), age (0.021), anti-viral use before admission (0.456), admission from long term care facility (0.002), obesity (0.319), exposed to children aged <5 years in household (0.005), current or past smoker (0.004), medications before onset of illness (0.087);