Table 1. Characteristics of 1,099 primary case-patients and 3,916 household contacts.
| Primary (n = 1,099) (%) | Secondary (n = 344) (%) | No symptoms (n = 3,572) (%) | |
|---|---|---|---|
| No. persons in household, median | 5* | 6 | 5* |
| <18 y | 2 | 3 | 2 |
| ≥18 y | 3 | 3 | 3 |
| Index case | 852 (78)* | 79 (23) | – |
| Member/index family | 1,052 (96)* | 295 (86) | 2,064 (58)* |
| Age, y, median | 3.6* | 12.6 | 24.7* |
| <2 | 412 (37) | 57 (17) | 138 (4) |
| 2–5 | 254 (23) | 50 (15) | 303 (8) |
| 6–17 | 145 (13) | 76 (22) | 670 (19) |
| ≥18 | 288 (26) | 161 (47) | 2,461 (69) |
| Male | 552 (50)* | 148 (43) | 1,803 (50)* |
| Daycare (if <6 y) | 148 (22) | 24 (22) | 108 (24) |
| Symptoms | |||
| Duration, median days | 3* | 1.3 | – |
| Vomiting with or without diarrhea | 799 (73)* | 194 (56) | – |
| Shares a bed with primary case-patient | – | 152 (44) | 776 (22)* |
| Exposed to vomiting, primary case-patient | – | 87 (25) | 649 (18)* |
*Univariate analysis, p<0.05 for comparison of secondary and primary cases, or secondary cases and other contacts of primary cases; –, not applicable.