Table 3.
Vaccine effectiveness (VE) of TIV against influenza-related hospitalization in patients ≥16 years (all adults group)
| 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 |
N number of patients, CI Confidence Interval, TIV trivalent influenza vaccine, VE vaccine effectiveness
Covariate (p-value in model):
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);
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);
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);
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);
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);
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);
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);