Table 2

Data of volunteers providing skin swab samples with concomitant reverse transcriptase-polymerase chain reaction (RT-PCR) verification

 CharacteristicsSkin swab samples used in the validation studySkin 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 screened301 (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)
 Outpatient117 (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 infection116 (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)NANANA
 SARS-CoV-2 variant*, n (%)
 Wild-type†62 (14.8)NA62 (54.4)2 (0.7)NA2 (66.7)
 Variant28 (6.7)NA28 (24.6)1 (0.4)NA1 (33.3)
 Alpha25 (6.0)NA25 (21.9)1 (0.4)NA1 (33.3)
 Beta1 (0.2)NA1 (0.9)0NA0
 Alpha or beta2 (0.5)NA2 (1.8)0NA0
 Unknown24 (5.7)NA24 (21.1)0NA0
 Chronic disease, n (%)
 Asthma, allergy28 (6.7)16 (5.2)12 (10.5)19 (6.3)18 (6.0)1 (33.3)
 Cancer7 (1.7)2 (0.7)5 (4.4)1 (0.3)1 (0.3)0 (0)
 Hypertension22 (5.2)14 (4.6)8 (7.0)25 (8.3)25 (8.3)0 (0)
 Diabetes11 (2.6)6 (2.0)5 (4.4)8 (2.6)8 (2.7)0 (0)
 Migraine3 (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.