Table 1.
Demographic and epidemiological characteristics of 13102 close contacts.
| Characteristic | Close contacts (n=13102) |
|---|---|
| Age group, years | |
| < 20 | 1497(11.43) |
| 20 ∼ 59 | 9516(72.63) |
| ≥ 60 | 2089(15.94) |
| Sex (n, %) | |
| Male | 7363(56.20) |
| Female | 5739(43.80) |
| Number of index cases | |
| 1 | 10236(78.13) |
| 2 | 1725(13.17) |
| ≥ 3 | 1140(8.70) |
| Unknown | 1(0.00) |
| Contact type (n, %) | |
| Household | 162(1.24) |
| Dine together | 752(5.74) |
| Socially interact | 2695(20.57) |
| Casual contact | 7086(54.08) |
| Multiple types | 8(0.06) |
| Unknown | 2399(18.31) |
| Frequency (n, %) | |
| Occasional | 5406(41.26) |
| Moderate | 4363(33.30) |
| Often | 427(3.26) |
| Unknown | 2906(22.18) |
| Time from onset to exposure, median (range), daysa | -1(-3,1) |
| Time from onset to exposure, daysa | |
| ≤ -5 | 1408(13.92) |
| -4 ∼ -1 | 5077(50.18) |
| 0 ∼ 3 | 2147(21.22) |
| 4 ∼ 6 | 487(4.81) |
| 7 ∼ 10 | 799(7.90) |
| > 10 | 200(1.98) |
a
Defined as the time period between the symptom onset of index cases and the exposure time of close contacts, the negative value means the close contacts have exposed to the index cases before the case had symptoms. The time from onset to exposure was estimated from those non-household close contacts linked to only 1 index case, thus the number of close contacts was 10118.