Characteristics of asymptomatic individuals with SARS-CoV-2 infection and symptomatic patients with COVID-19*
| Asymptomatic individuals (n=39) | Symptomatic patients (n=144) | P value | |
| Age, median (IQR), y | 25.0 (21.5–34.0) | 26.5 (22.0–46.0) | 0.22 |
| Male sex, n (%) | 22 (56) | 62 (43) | 0.14 |
| Underlying diseases, n (%) | 3 (8) | 26 (18) | 0.12 |
| Hypertension | 0 | 5 | |
| Asthma | 0 | 4 | |
| Liver disease | 0 | 2 | |
| COPD | 0 | 1 | |
| Solid cancer | 0 | 1 | |
| Rheumatologic disease | 1 | 0 | |
| Other | 2† | 13‡ | |
| Interval from the first swab for diagnosis to the start of isolation, median (IQR), days | 6.0 (4.5–7.0) | 6.0 (4.0–9.0) | 0.84 |
| Interval from initial confirmation to follow-up RT-PCR testing, median (IQR), days | 12 (9–14) | 13 (11–15) | 0.06 |
| Interval from symptom onset to follow-up RT-PCR testing, median (IQR), days | NA | 26±6 | NA |
| Positive result on follow-up RT-PCR testing, n (%) | 21 (54) | 92 (64) | 0.25 |
| Ct values, mean±SD | |||
| E gene | 31.15±2.72 | 31.43±2.80 | >0.99 |
| RdRp gene | 32.26±2.86 | 32.93±2.87 | 0.92 |
| N gene | 33.05±2.52 | 33.28±2.48 | >0.99 |
*Categorical variables were compared using the Fisher’s exact test or χ2 test, as appropriate, and continuous variables were compared using the Mann-Whitney U test or Student’s t-test. All tests of significance were two-tailed.
†Includes thyroid disease (n=1) and allergic rhinitis (n=1).
‡Includes allergic rhinitis (n=8), hyperlipidaemia (n=2), thyroid disease (n=2) and nephrotic syndrome (n=1).
Ct, cycle threshold; NA, not available; RT-PCR, reverse transcription-PCR.