Data of volunteers providing skin swab samples with concomitant reverse transcriptase-polymerase chain reaction (RT-PCR) verification
| Characteristics | Skin swab samples used in the validation study | Skin swab samples sniffed by the validated dogs during operational work | ||||
| Overall (n=420) | RT-PCR negative (n=306) | RT-PCR positive (n=114) | Overall (n=303) | RT-PCR negative (n=300) | RT-PCR positive (n=3) | |
| Age, median (IQR) | 38 (21) | 40 (23) | 34 (18) | 42 (22) | 42 (23) | 48 (NA) |
| Child, 0–12 years, n (%) | 15 (3.6) | 2 (0.7) | 13 (11.4) | 2 (0.7) | 2 (0.7) | 0 (0) |
| Sex, female, n (%) | 226 (53.8) | 168 (54.9) | 58 (50.9) | 192 (63.4) | 191 (63.7) | 1 (33.3) |
| Male, n (%) | 192 (45.7) | 137 (44.8) | 55 (48.2) | 111 (36.6) | 109 (36.3) | 2 (66.7) |
| Sample obtained, n (%) | ||||||
| Healthy screened | 301 (71.7) | 301 (98.3) | 0 (0) | 303 (100) | 300 (100) | 3 (100) |
| Hospitalised (non-COVID respiratory disease) | 2 (0.5) | 2 (0.7) | 0 (0) | 0 (0) | 0 (0) | 0 (0) |
| Outpatient | 117 (27.9) | 3 (1.0) | 114 (100) | 0 (0) | 0 (0) | 0 (0) |
| Days between PCR test and sampling, days, median (IQR) | 0 (2) | 0 (1) | 2 (1) | 0 (0) | 0 (0) | 0 (0) |
| Symptoms, n (%) Asymptomatic | 304 (72.4) | 297 (97.1) | 7 (6.1) | 293 (96.7) | 291 (97.0) | 2 (66.7) |
| Respiratory infection | 116 (27.6) | 9 (2.9) | 107 (93.9) | 10 (3.3) | 9 (3.0) | 1 (33.3) |
| Days between start of symptoms and sampling, days, median (IQR) | 4 (3) | 3 (17) | 4 (3) | NA | NA | NA |
| SARS-CoV-2 variant*, n (%) | ||||||
| Wild-type† | 62 (14.8) | NA | 62 (54.4) | 2 (0.7) | NA | 2 (66.7) |
| Variant | 28 (6.7) | NA | 28 (24.6) | 1 (0.4) | NA | 1 (33.3) |
| Alpha | 25 (6.0) | NA | 25 (21.9) | 1 (0.4) | NA | 1 (33.3) |
| Beta | 1 (0.2) | NA | 1 (0.9) | 0 | NA | 0 |
| Alpha or beta | 2 (0.5) | NA | 2 (1.8) | 0 | NA | 0 |
| Unknown | 24 (5.7) | NA | 24 (21.1) | 0 | NA | 0 |
| Chronic disease, n (%) | ||||||
| Asthma, allergy | 28 (6.7) | 16 (5.2) | 12 (10.5) | 19 (6.3) | 18 (6.0) | 1 (33.3) |
| Cancer | 7 (1.7) | 2 (0.7) | 5 (4.4) | 1 (0.3) | 1 (0.3) | 0 (0) |
| Hypertension | 22 (5.2) | 14 (4.6) | 8 (7.0) | 25 (8.3) | 25 (8.3) | 0 (0) |
| Diabetes | 11 (2.6) | 6 (2.0) | 5 (4.4) | 8 (2.6) | 8 (2.7) | 0 (0) |
| Migraine | 3 (0.7) | 2 (0.7) | 1 (0.9) | 3 (1.0) | 3 (1.0) | 0 (0) |
*SARS-CoV-2 variant status was determined using S-Gene Target Failure (for alpha), N501Y Mutation PCR (for alpha or beta) and/or gene sequencing (for beta and some alphas) combined with epidemiological information (first alpha variant cases were detected 18 December in Finland).
†Wild-type refers to Wuhan-like lineages.