Table 2.
Cox multivariate regression model indicating associations between the occurrence of breakthrough infection with SARS-CoV-2 and characteristics evaluated (N = 309).
| Variable | Hazard Ratio | SE | 95% CI | p-Value |
|---|---|---|---|---|
| Log likelihood = −507.17; χ2 = 27.39 (4 df); p-value < 0.0001 | ||||
| Previous infection with SARS-CoV-2 | 0.01 | |||
| No | Ref. | - | - | |
| Yes | 0.32 | 0.15 | 0.13–0.80 | |
| Age (continuous, in years) | 0.97 | 0.01 | 0.96–0.99 | 0.01 |
| Professional role | 0.001 | |||
| Non-HCWs | Ref. | - | - | |
| HCWs | 0.49 | 0.11 | 0.32–0.76 | |
| Smoking habits | 0.08 | |||
| Never/former smoker | Ref. | - | - | |
| Cigarette smoker | 0.61 | 0.17 | 0.35–1.06 | |
| E-cigarette user/Dual user | Omitted for p-value > 0.4 | |||
Abbreviations: HCWs, healthcare workers; SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus 2; Ref., reference category; 95% CI, 95% confidence interval; SE, standard error; df, degrees of freedom.