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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);