Table 4.
Unadjusted and adjusted odds ratios modeling the likelihood of whether a GI or GII NoV strain is associated with an outbreak that is characterized by the presence of potential NoV risk factors.
| Variable | Unadjusted* | Adjusted, no multiple transmission routes (n=184) |
Adjusted, with multiple transmission routes (n=281) |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|
| OR† | 95% CI | n | OR† | 95% CI | OR† | 95% CI | ||||
| Transmission | 339 | |||||||||
| Foodborne | 0.46 | 0.19 | 1.11 | 2.21 | 0.42 | 11.52 | 1.33 | 0.49 | 3.62 | |
| Waterborne | 0.10‡ | 0.04 | 0.29 | 0.42 | 0.07 | 2.33 | 0.19‡ | 0.05 | 0.67 | |
| Environmental | 0.81 | 0.03 | 23.34 | 0.93 | 0.01 | 60.48 | 2.16 | 0.35 | 13.49 | |
| Person-to-Person | Ref. | - | - | Ref. | - | - | Ref. | - | - | |
| Setting | 545 | |||||||||
| Foodservice | 1.05 | 0.52 | 2.15 | 0.86 | 0.13 | 5.80 | 1.46 | 0.37 | 5.70 | |
| Healthcare | 4.37‡ | 1.67 | 11.43 | 20.47 | 0.81 | 520.49 | 33.67‡ | 1.76 | 644.18 | |
| Leisure | 0.83 | 0.35 | 1.96 | 0.93 | 0.13 | 6.55 | 2.77 | 0.70 | 10.98 | |
| Other | 0.93 | 0.38 | 2.28 | 0.86 | 0.11 | 6.88 | 2.42 | 0.47 | 12.43 | |
| School/Daycare | Ref. | - | - | Ref. | - | - | Ref. | - | - | |
| Season | 552 | |||||||||
| Winter | 2.17‡ | 1.14 | 4.10 | 8.76‡ | 2.43 | 31.56 | 5.34‡ | 1.94 | 14.73 | |
| Spring | 1.21 | 0.62 | 2.39 | 1.54 | 0.47 | 4.97 | 0.99 | 0.38 | 2.58 | |
| Summer | 0.92 | 0.44 | 1.93 | 2.71 | 0.83 | 8.87 | 2.27 | 0.83 | 6.19 | |
| Fall | Ref. | - | - | Ref. | - | - | Ref. | - | - | |
| Action to stop transmission | 600 | |||||||||
| Described in article | 0.73 | 0.38 | 1.42 | 0.51 | 0.18 | 1.44 | 0.68 | 0.30 | 1.52 | |
| Not described | Ref. | - | - | Ref. | - | - | Ref. | - | - | |
| Outbreak Year | 1.00 | 1.00 | 1.00 | 600 | ||||||
| Primary Attack Rate | 1.00 | 0.99 | 1.01 | 366 | 1.00 | 0.99 | 1.02 | 1.00 | 0.98 | 1.01 |
*
Unadjusted analyses excluded outbreaks with multiple modes of transmission.
†
Significant odds ratios (ORs) greater than one represent that the odds an outbreak was caused by a GII strain were greater than the odds an outbreak was caused by a GI strain.
‡
p < 0.05.