Table 1 Baseline characteristics of the eligible (before-match) and matched cohorts of adult close contacts of COVID-19 who received 2-dose and 3-dose vaccine
Characteristics | Eligible cohorts | Matched cohorts | ||||
|---|---|---|---|---|---|---|
2 doses, n (column %) | 3 doses, n (column %) | SMD | 2 doses, n (column %) | 3 doses, n (column %) | SMD | |
Total | 3433 (100%) | 33,666 (100%) | NA | 3317 (100%) | 16,051 (100%) | NA |
Sex | ||||||
 Male | 1571 (45.8%) | 16,061 (47.7%) | 0.039 | 1555 (46.9%) | 7388 (46.0%) | 0.017 |
 Female | 1862 (54.2%) | 17,605 (52.3%) | 1762 (53.1%) | 8663 (54.0%) | ||
Age group | ||||||
 Young adult: 18–39 yr | 1868 (54.4%) | 16,241 (48.2%) | 0.483 | 1868 (56.3%) | 9313 (58.0%) | 0.071 |
 Middle-age adult: 40–59 yr | 851 (24.8%) | 14,665 (43.6%) | 851 (25.7%) | 4271 (26.6%) | ||
 Old-age adult: 60+ yr | 714 (20.8%) | 2760 (8.2%) | 598 (18.0%) | 2467 (15.4%) | ||
Median age, yr [IQR] | 37.0 [28.0, 55.0] | 40.0 [31.0, 51.0] | 0.074 | 36.0 [28.0, 53.0] | 36.0 [28.0, 51.0] | 0.070 |
Epidemiological week of 2022 | ||||||
 wk 31: Jul 31–Aug 6 | 775 (22.6%) | 7230 (21.5%) | 0.077 | 749 (22.6%) | 3644 (22.7%) | 0.047 |
 wk 32: Aug 7–Aug 13 | 1683 (49.0%) | 17,510 (52.0%) | 1670 (50.3%) | 8261 (51.5%) | ||
 wk 33: Aug 14–Aug 20 | 470 (13.7%) | 3992 (11.9%) | 406 (12.2%) | 1970 (12.3%) | ||
 wk 34: Aug 21–Aug 27 | 306 (8.9%) | 2835 (8.4%) | 293 (8.8%) | 1236 (7.7%) | ||
 wk 35: Aug 28–Sep 3 | 127 (3.7%) | 1257 (3.7%) | 127 (3.8%) | 562 (3.5%) | ||
 wk 36: Sep 4–Sep 10 | 72 (2.1%) | 842 (2.5%) | 72 (2.2%) | 378 (2.4%) | ||
Contact setting | ||||||
 Household | 101 (2.9%) | 874 (2.6%) | 0.069 | 94 (2.8%) | 373 (2.3%) | 0.036 |
 Community | 131 (3.8%) | 1198 (3.6%) | 119 (3.6%) | 551 (3.4%) | ||
 Workplace | 94 (2.7%) | 1317 (3.9%) | 94 (2.8%) | 497 (3.1%) | ||
 Unknown settings | 3107 (90.5%) | 30,277 (89.9%) | 3010 (90.7%) | 14,630 (91.1%) | ||
Age group of source case | ||||||
 Minor: < 18 yr | 230 (6.7%) | 1784 (5.3%) | 0.107 | 210 (6.3%) | 871 (5.4%) | 0.070 |
 Young adult: 18–39 yr | 1428 (41.6%) | 15,193 (45.1%) | 1428 (43.1%) | 7223 (45.0%) | ||
 Middle-age adult: 40–59 yr | 1511 (44.0%) | 14,733 (43.8%) | 1469 (44.3%) | 6995 (43.6%) | ||
 Old-age adult: 60+ yr | 264 (7.7%) | 1956 (5.8%) | 210 (6.3%) | 962 (6.0%) | ||
Vaccine status of source case | ||||||
 0–1 dose | 267 (7.8%) | 2473 (7.3%) | 0.054 | 261 (7.9%) | 1130 (7.0%) | 0.051 |
 2 doses | 457 (13.3%) | 3928 (11.7%) | 407 (12.3%) | 1881 (11.7%) | ||
 3 doses | 2709 (78.9%) | 27,265 (81.0%) | 2649 (79.9%) | 13,040 (81.2%) | ||