Table 2.
The effect of smoking on the incidence rate of influenza in people not previously vaccinated and stratified according to current vaccination status (rate as %)
| Number of people (rate) |
Influenza in smokers compared to non-smokers |
|||||
|---|---|---|---|---|---|---|
| Influenza according to | Vaccine or placebo | smoker (n=321)a | non-smoker (n=1152)b | rate difference (95% CI)c,d | odds ratio (95% CI)c,e | logistic regression odds ratio (95% CI)c,f |
| Serology | vaccine | 4/151 (3%) | 34/578 (6%) | −3% (−6%–2%) | 0.44 (0.15–1.25) | 0.51 (0.18–1.50) |
| placebo | 21/166 (13%) | 44/552 (8%) | 5% (−1%–11%) | 1.67 (0.96–2.90) | 1.61 (0.91–2.83) | |
| Sentinel stations | vaccine | 8/153 (5%) | 37/590 (6%) | −1% (−5%–3%) | 0.82 (0.38–1.80) | 0.89 (0.39–2.00) |
| placebo | 16/168 (10%) | 57/562 (10%) | 0% (−5%–5%) | 0.93 (0.52–1.67) | 0.96 (0.53–1.75) | |
a
Includes 4 missing values for serological influenza.
bIncludes 22 missing values for serological influenza.
cCI indicates confidence interval.
dAccording to Ref[14].
eNot corrected for covariables.
fCorrected for age, sex and risk group, but not for protective titre before vaccination (possible intermediate factor).