Table 3.
Frequencies of positive antibody tests stratified according to exposure
| Seronegative, n (%) | Seropositive, n (%) | OR (95% CI) | P-value | |
|---|---|---|---|---|
| Number of close physical contacts per day outside work | ||||
| <10 | 2515 (98.5%) | 39 (1.5%) | 1.00 (Ref.) | |
| 11–50 | 4855 (97.7%) | 116 (2.3%) | 1.54 (1.07; 2.22) | 0.021 |
| 51–100 | 309 (97.5%) | 8 (2.5%) | 1.67 (0.77; 3.61) | 0.192 |
| >100 | 36 (94.7%) | 2 (5.3%) | 3.58 (0.83; 15.40) | 0.086 |
| Working from home 4 weeks up to answered questionnaire | ||||
| No | 6607 (97.8%) | 146 (2.2%) | 1.00 (Ref.) | |
| Yes, mainly | 456 (98.9%) | 5 (1.1%) | 0.50 (0.20; 1.22) | 0.125 |
| Yes, partly | 634 (98.1%) | 12 (1.9%) | 0.86 (0.47; 1.55) | 0.609 |
| Working from home in the period from mid-March to mid-April 2020 | ||||
| No | 6128 (97.8%) | 135 (2.2%) | 1.00 (Ref.) | |
| Yes, mainly | 752 (98.7%) | 10 (1.3%) | 0.60 (0.32; 1.15) | 0.126 |
| Yes, partly | 817 (97.8%) | 18 (2.2%) | 1.00 (0.61; 1.64) | 1.000 |
| Any travel history 2020 | ||||
| No | 5071 (98.0%) | 102 (2.0%) | 1.00 (Ref.) | |
| Yes | 2713 (97.7%) | 64 (2.3%) | 1.17 (0.86; 1.61) | 0.323 |
| Any travel history 2020 (within Europe) | ||||
| No | 5382 (98.0%) | 110 (2.0%) | 1.00 (Ref.) | |
| Yes | 2402 (97.7%) | 56 (2.3%) | 1.14 (0.82; 1.58) | 0.428 |
| Travel history within 2020, but before serological testing | ||||
| Italy | 138 (97.2%) | 4 (2.8%) | 1.37 (0.50; 3.74) | 0.542 |
| Austria | 484 (98.2%) | 9 (1.8%) | 0.86 (0.44; 1.70) | 0.674 |
| Spain | 308 (98.7%) | 4 (1.3%) | 0.60 (0.22; 1.63) | 0.315 |
| France | 118 (99.2%) | 1 (0.8%) | 0.39 (0.05; 2.84) | 0.355 |
| Belgium | 8 (80.0%) | 2 (20.0%) | 11.85 (2.50; 56.25) | 0.002 |
| Netherlands | 42 (100.0%) | 0 (0.0%) | - | - |
| Great Britain | 88 (96.7%) | 3 (3.3%) | 1.61 (0.50; 5.14) | 0.422 |
| Other European countries | 1575 (97.8%) | 35 (2.2%) | 1.05 (0.72; 1.54) | 0.787 |
| China | 5 (100.0%) | 0 (0.0%) | - | - |
| Iran | 1 (100.0%) | 0 (0.0%) | - | - |
| Asia (except China and Iran) | 209 (98.6%) | 3 (1.4%) | 0.67 (0.21; 2.11) | 0.490 |
| Australia | 20 (95.2%) | 1 (4.8%) | 2.35 (0.31; 17.63) | 0.405 |
| Africa | 75 (97.4%) | 2 (2.6%) | 1.25 (0.31; 5.15) | 0.754 |
| North America | 69 (100.0%) | 0 (0.0%) | - | - |
| South America | 27 (93.1%) | 2 (6.9%) | 3.50 (0.83; 14.86) | 0.089 |
| None of the above | 5004 (98.0%) | 101 (2.0%) | 0.86 (0.63; 1.18) | 0.360 |
| Geographical workplace | ||||
| Funen | 3484 (97.9%) | 74 (2.1%) | 1.00 (Ref.) | |
| Lillebælt | 2152 (97.6%) | 53 (2.4%) | 1.16 (0.81; 1.66) | 0.416 |
| Southern Jutland | 888 (99.2%) | 7 (0.8%) | 0.37 (0.17; 0.81) | 0.013 |
| South West Jutland | 918 (97.2%) | 26 (2.8%) | 1.33 (0.85; 2.10) | 0.213 |
| Other | 342 (98.3%) | 6 (1.7%) | 0.83 (0.36; 1.91) | 0.655 |
| Area of residence | ||||
| Funen | 3621 (97.8%) | 83 (2.2%) | 1.00 (Ref.) | |
| South Jutland | 3746 (98.1%) | 73 (1.9%) | 0.85 (0.62; 1.17) | 0.317 |
| Region Central Jutland | 281 (97.9%) | 6 (2.1%) | 0.93 (0.40; 2.15) | 0.868 |
| Region Northern Jutland | 3 (100.0%) | 0 (0.0%) | - | - |
| Region Zealand | 18 (100.0%) | 0 (0.0%) | - | - |
| Capital Region | 24 (92.3%) | 2 (7.7%) | 3.64 (0.85; 15.64) | 0.083 |
| Outside Denmark | 25 (96.2%) | 1 (3.8%) | 1.75 (0.23; 13.03) | 0.587 |
| Unknown | 66 (98.5%) | 1 (1.5%) | 0.66 (0.09; 4.82) | 0.683 |
OR, odds ratio; CI, confidence interval.