Table 3.
Characteristics associated with presence of antibodies against severe acute respiratory syndrome coronavirus-2 spike protein among health care workers, February–May 2021a.
| Characteristics N = 1493 | Antibodies against SARS-CoV-2 spike protein |
Unadjusted Odds Ratio (OR) |
Adjusted Odds Ratio (aOR) |
|||
|---|---|---|---|---|---|---|
| Negative N = 417 (%) | Positive N = 1076 (%) | OR (95% CI) | p-value | aOR (95% CI) | p-value | |
| Age group (years) | – | – | – | – | – | – |
| ≤34 (n = 416) | 103 (24.8) | 313 (75.2) | Reference | – | Reference | – |
| 35–59 (n = 972) | 282 (29.0) | 690 (71.0) | 0.81 (0.62–1.05) | 0.105 | 0.88 (0.67–1.16) | 0.362 |
| ≥60 (n = 105) | 32 (30.5) | 73 (69.5) | 0.75 (0.47–1.20) | 0.233 | 0.85 (0.52–1.40) | 0.529 |
| Gender | – | – | – | – | – | – |
| Male (n = 316) | 111 (35.1) | 205 (64.9) | Reference | – | Reference | – |
| Female (n = 1177) | 306 (26.0) | 871 (74.0) | 1.54 (1.18–2.01) | 0.001 | 1.22 (0.90–1.65) | 0.210 |
| Smoking habits | – | – | – | – | – | – |
| Never smoked (n = 1224) | 320 (26.1) | 904 (73.9) | Reference | – | Reference | – |
| Previous smoker (n = 68) | 14 (20.6) | 54 (79.4) | 1.36 (0.74–2.49) | 0.31 | 1.74 (0.94–3.22) | 0.080 |
| Current smoker (n = 201) | 83 (41.3) | 118 (58.7) | 0.50 (0.37–0.69) | <0.001 | 0.55 (0.40–0.75) | <0.001 |
| Study site | – | – | – | – | – | – |
| Fier Hospital (n = 296) | 96 (32.4) | 200 (67.6) | Reference | – | Reference | – |
| Durres Hospital (n = 262) | 85 (32.4) | 177 (67.6) | 1.00 (0.70–1.43) | 0.998 | 1.04 (0.72–1.50) | 0.847 |
| Tirana University Hospital (n = 935) | 236 (25.2) | 699 (74.8) | 1.42 (1.07–1.89 | 0.015 | 1.46 (1.09–1.96) | 0.011 |
| Occupation | – | – | – | – | – | – |
| Physicians (n = 296) | 95 (32.1) | 201 (67.9) | Reference | – | Reference | – |
| Nurse, midwifes (n = 713) | 164 (23.0) | 549 (77.0) | 1.58 (1.17–2.14) | 0.003 | 1.45 (1.05–2.02) | 0.026 |
| Support staff (n = 195) | 55 (28.2) | 140 (71.8) | 1.20 (0.81–1.79) | 0.360 | 1.57 (1.03–2.41) | 0.039 |
| Administrative staff (n = 289) | 103 (35.5) | 186 (64.5) | 0.85 (0.61–1.20) | 0.365 | 1.02 (0.71–1.50) | 0.886 |
| Regular performance of aerosol generating procedures | – | – | – | – | – | – |
| No (n = 741) | 243 (32.8) | 498 (67.2) | Reference | – | Reference | – |
| Yes (n = 752) | 174 (23.1) | 578 (76.9) | 1.62 (1.29–2.04) | <0.001 | 1.40 (1.01-1.94) | 0.044 |
| Patient-facing Role | – | – | – | – | – | – |
| No (n = 594) | 192 (32.3) | 402 (67.7) | Reference | – | Reference | – |
| Yes (n = 899) | 225 (25.0) | 674 (75.0) | 1.43 (1.13–1.80) | 0.002 | 1.01 (0.62–1.63) | 0.976 |
| Influenza vaccination 2020/2021 | – | – | – | – | – | – |
| No (n = 1075) | 287 (26.7) | 788 (73.3) | Reference | – | Reference | – |
| Yes (n = 418) | 130 (31.1) | 288 (68.9) | 0.81 (0.63–1.03) | 0.089 | 0.82 (0 59–1.15) | 0.254 |
| Any patient contact | – | – | – | – | – | – |
| No (n = 70) | 21 (30.0) | 49 (70.0) | Reference | – | – | – |
| Yes (n = 1423) | 396 (27.8) | 1027 (72.2) | 1.11 (0.66–1.88) | 0.693 | – | – |
| Care for older patients (≥65 years) | – | – | – | – | – | – |
| No (n = 682) | 195 (28.6) | 487 (71.4) | Reference | – | – | – |
| Yes (n = 811) | 222 (27.4) | 589 (72.6) | 1.06 (0.85–1.33) | 0.601 | – | – |
| Body mass indexb | – | – | – | – | – | – |
| ≤24.9 (n = 633) | 187 (29.5) | 446 (70.5) | Reference | – | – | – |
| ≥25.0–29.9 (n = 589) | 157 (26.7) | 432 (73.3) | 1.15 (0.90–1.48) | 0.262 | – | – |
| ≥30.0 (n = 271) | 73 (26.9) | 198 (73.1) | 1.13 (0.83–1.56) | 0.428 | – | – |
| Pre-existing conditions | – | – | – | – | – | – |
| No (n = 1203) | 337 (28.0) | 866 (72.0) | Reference | – | – | – |
| Yes (n = 290) | 80 (27.6) | 210 (72.4) | 1.02 (0.77–1.36) | 0.884 | – | – |
| Household size | – | – | – | – | – | – |
| Live with 1 person (n = 23) | 7 (30.4) | 16 (69.6) | Reference | – | – | – |
| Live with 2 people (n = 166) | 41 (24.7) | 125 (75.3) | 1.33 (0.51–3.47) | 0.555 | – | – |
| Live with 3 people (n = 385) | 114 (29.6) | 271 (70.4) | 1.04 (0.42–2.60) | 0.933 | – | – |
| Live with 4 people (n = 475) | 125 (26.3) | 350 (73.7) | 1.23 (0.50–3.05) | 0.663 | – | – |
| Live with ≥5 people (n = 444) | 130 (29.3) | 314 (70.7) | 1.06 (0.42–2.63) | 0.906 | – | – |
a
Excluding 11 participants who received their first COVID-19 vaccine >5 days before enrollment in the study.
b
Body mass index was calculated based on self-reported height and weight and grouped into the following three categories: 1) underweight (<18.5) and healthy weight (18.5–24.9), 2) overweight (25.0–29.9), and 3) obesity (≥30.0).