Table 1 Study population of the descriptive analysis of index cases of SARS-CoV-2 infection with a confirmed source case within their households
TOTAL | 104,373 |
Age – median [IQR] (years) | 42 [36–50] |
Female | 76,664 (73.5%) |
Education level | |
No diploma | 1687 (1.6%) |
Pre-high school diploma | 11,778 (11.3%) |
High-school diploma | 17,513 (16.8%) |
Bachelor’s degree | 39,281 (37.4%) |
Master’s degree or higher | 34,114 (32.7%) |
Underlying conditions | |
Chronic respiratory disease | 8223 (7.9%) |
Hypertension | 7541 (7.2%) |
Diabetes mellitus | 2315 (2.2%) |
Coronary artery disease | 578 (0.6%) |
COVID-19 vaccination status | |
Unvaccinated | 40,529 (38.8%) |
1 dose | 2294 (2.2%) |
2 doses | 26,597 (25.5%) |
3 doses | 34,752 (33.3%) |
4 doses | 201 (0.2%) |
Symptomatic COVID-19 | 90,371 (86.6%) |
Variant | |
Original strain | 3219 (3.1%) |
Alpha | 10,625 (10.2%) |
Beta/Gamma | 916 (0.9%) |
Delta | 10,098 (9.7%) |
Omicron | 12,511 (12.0%) |
Other | 144 (0.1%) |
Undetermined | 66,860 (64.1%) |
Number of household members (median [IQR]) | 4 [3, 4] |
SOURCE CASE | |
Age – median [IQR] (years) | 26 [11–45] |
Female | 41,245 (39.5%) |
Symptomatic | 91,302 (87.5%) |
Isolation overall from the index case | 56,415 (54.1%) |
Isolation timing | |
From symptom onset | 18,688 (17.9%) |
From test results | 35,278 (33.8%) |
Other timing | 2449 (2.4%) |
Mitigation measures | |
Ventilation (10–15 min at least twice/day) | 52,150 (50.0%) |
Mask-wearing | 45,310 (43.4%) |
Surface disinfection | 41,734 (40.0%) |
Separate bathrooms | 21,970 (21.1%) |
Separate meals | 40,706 (39.0%) |
Relationship of the source case to the index case | |
Child | 48,971 (46.9%) |
Partner | 47,726 (45.7%) |
Mother/father | 3013 (2.9%) |
Sibling | 1462 (1.4%) |
Other | 3201 (3.1%) |