Table 6. Summary of multivariate logistic regression model predicting probable secondary infection” at household members (N = 2,195).
| Risk factor | Coefficient | S.E. | Odds ratio (95% CI) | p value |
|---|---|---|---|---|
| Type of Index Person (IP) |
|
|
|
|
| Hospital care workers |
|
|
1.00 |
|
| Amoy Gardens Block E residents |
2.888 |
0.455 |
17.95 (7.35 to 43.83) |
<0.001 |
| Amoy Gardens other Block residents |
1.661 |
0.419 |
5.26 (2.32 to 11.95) |
<0.001 |
| Other community members |
1.387 |
0.352 |
4.01 (2.01 to 7.98) |
<0.001 |
| IP visited by a household member |
|
|
|
|
| Not visited by any |
|
|
1.00 |
|
| Both with mask |
0.571 |
0.412 |
1.77 (0.79 to 3.97) |
0.166 |
| Either one with mask |
0.483 |
0.429 |
1.62 (0.70 to 3.76) |
0.260 |
| Both without mask |
1.139 |
0.326 |
3.12 (1.65 to 5.91) |
<0.001 |
| Frequency of close contact with IP (within 1 m)a |
|
|
|
|
| Never |
|
|
1.00 |
|
| Seldom |
0.466 |
0.338 |
1.59 (0.82 to 3.09) |
0.168 |
| Occasionally |
0.762 |
0.304 |
2.14 (1.18 to 3.89) |
0.012 |
| Frequently |
0.834 |
0.288 |
2.30 (1.31 to 4.05) |
0.004 |
| Date of IP’s fever onset |
|
|
|
|
| Before March 25 |
|
|
1.00 |
|
| On or after March 25 |
–0.681 |
0.220 |
0.51 (0.33 to 0.78) |
0.002 |
| Duration Index person stayed home between fever onset and hospitalization (d) |
|
|
|
|
| ≤2 |
|
|
1.00 |
|
| 3-5 |
0.092 |
0.278 |
1.10 (0.64 to 1.89) |
0.740 |
| ≥ 6 | 0.655 | 0.278 | 1.93 (1.12 to 3.32) | 0.018 |
aInformation on 13 cases and 37 controls missing.