Table 2.
Number of norovirus outbreaks by polymerase type, gender, age, symptoms, and magnitude of outbreak *.
| Characteristics of Outbreaks | Other Polymerases Total (%) |
Novel GII.P16 Total (%) |
OR (99% CI) | Total No. | |
|---|---|---|---|---|---|
| Gender | <50% Female | 88 (55.0) | 72 (45.0) | 1.00 | 160 |
| ≥50% Female | 187 (54.5) | 156 (45.5) | 1.02 (0.62–1.68) | 343 | |
| Age, y | <50% 75 or older | 181 (58.6) | 128 (41.4) | 1.00 | 309 |
| ≥50% 75 or older | 68 (52.3) | 62 (47.7) | 1.29 (0.75–2.22) | 130 | |
| Symptoms | |||||
| Abdominal cramps | <50% cases | 153 (54.1) | 130 (45.9) | 1.00 | 283 |
| ≥50% cases | 63 (55.8) | 50 (44.2) | 0.93 (0.52–1.66) | 113 | |
| Fever | <50% cases | 211 (52.2) | 193 (47.8) | 1.00 | 404 |
| ≥50% cases | 24 (66.7) | 12 (33.3) | 0.55 (0.20–1.39) | 36 | |
| Vomiting | <50% cases | 130 (51.8) | 121 (48.2) | 1.00 | 251 |
| ≥50% cases | 155 (56.6) | 119 (43.4) | 0.83 (0.52–1.30) | 274 | |
| Diarrhea | <50% cases | 87 (43.4) | 76 (46.6) | 1.00 | 163 |
| ≥50% cases | 195 (53.6) | 169 (46.4) | 0.99 (0.61–1.62) | 364 | |
| Magnitude | 0–23 cases | 165 (55.2) | 134 (44.8) | 1.00 | 299 |
| 24–313 cases | 140 (46.8) | 159 (53.2) | 1.40 (0.92–2.14) | 299 | |
* Other Polymerases include GII.P2, GII.P12, extant GII.P16, GII.P17, GII.P21, GII.Pe, GII.Pg, and GII.Pq; OR: Odds ratio; Magnitude is characterized based on estimated primary ill by outbreak and cut off was defined by the median.