Table 2. Symptoms and exposure history of persons testing positive for SARS-CoV-2, stratified by ability to culture virus and RT-PCR/antigen test concordance, Winnebago County, Wisconsin, USA, November-December 2020*.
| Characteristic | Culture positive |
Culture negative |
|||||
|---|---|---|---|---|---|---|---|
| RT-PCR+/ antigen–, n = 9 | RT-PCR+/ antigen+, n = 191 | All, n = 200 | RT-PCR+/ antigen–, n = 58 | RT-PCR+/ antigen+, n = 76 | All, n = 134† | ||
| Symptomatic | |||||||
| Current symptoms | 7 (77.8) | 165 (88.2) | 172 (87.8) | 43 (73.7) | 67 (88.2) | 109 (82.0) | |
| No current symptoms | 2 (22.2) | 22 (11.8) | 24 (12.2) | 15 (26.3) | 9 (11.8) | 24 (18.0) | |
| Unknown/missing |
0 |
4 |
4 |
|
1 |
|
1 |
| Meets CSTE clinical criteria‡ | |||||||
| Yes | 7 (77.8) | 142 (74.3) | 149 (74.5) | 36 (62.1) | 60 (78.9) | 96 (71.6) | |
| No |
2 (22.2) |
49 (25.7) |
51 (25.5) |
|
22 (37.9) |
16 (21.1) |
38 (28.4) |
| Days from symptom onset to specimen collection, median (IQR) |
2 (1–6 d) |
3 (1–4) |
3 (1–5) |
|
3 (1–10) |
4 (2–7) |
4 (2–7) |
| Known exposure in previous 14 d | |||||||
| Yes | 5 (55.6) | 111 (58.7) | 116 (58.6) | 34 (59.7 | 39 (52.0) | 73 (55.3) | |
| No | 1 (11.1) | 42 (22.2) | 43 (21.7) | 19 (33.3) | 22 (29.3) | 41 (31.1) | |
| Unknown | 3 (33.3) | 36 (19.1) | 39 (19.7) | 4 (7.0) | 14 (18.7) | 18 (13.6 | |
| Missing |
0 |
2 |
2 |
|
1 |
1 |
2 |
| Days since last known exposure, median (IQR) |
2 (0.5–4) |
4 (0–6) |
4 (0–6) |
|
2 (0–4 d) |
3 (0–7) |
2 (0–6) |
| N gene Ct value, median (IQR) | 26.6 (25.6–31.0) | 19.1 (17.1–21.3) | 19.2 (17.2–21.7) | 30.9 (29.3–33.4) | 24.3 (21.1–27.7) | 27.9 (23.8–30.9) | |
*Values are no. (%) except as indicated. CSTE, Council of State and Territorial Epidemiologists; Ct , cycle threshold; IQR, interquartile range; N, nucleocapsid; RT-PCR, reverse transcription PCR; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; +, positive; ‒, negative. †All specimen pairs included tested positive by RT-PCR; the 2 participants who had false-positive antigen test results, both of whom were culture negative, were excluded. ‡CSTE clinical criteria are met if the case-patient has either cough, shortness of breath, loss of taste, or loss of smell, or >2 of the following symptoms: fever, chills, myalgia, headache, or sore throat.