Table 4.
Norovirus Genogroup and Genotype Results of Sporadic Cases and Outbreaks by Seasonal Onset
| Sporadic Cases (%) n = 755 | Outbreaks (%) n = 45 | |||||
|---|---|---|---|---|---|---|
| Genogroups and Genotypes | Winter (November—April) | Summer (May—October) | P Valuea | Winter (November—April) | Summer (May—October) | P Valuea |
| GI | 38 (56.7) | 29 (43.3) | 5 (83.3) | 1 (16.7) | ||
| GI and GII | 6 (75.0) | 2 (25.0) | 0 | 0 | ||
| GII.4 | 246 (83.3)b | 49 (16.7) | 16 (84.2)c | 3 (15.8) | ||
| Non-GII.4 | 181 (68.3)b | 84 (31.7) | 9 (81.8)c | 2 (18.2) | ||
| GII untypeable | 95 (79.2) | 25 (20.8) | 0 | 0 | ||
| 0 | 0 | 9 (100) | 0 | |||
| Indeterminate | ||||||
| <.001 | >.05 |
aIndicates statistical significance of the χ2or Fisher exact test between genogroup and genotype classification and seasonal onset of surveillance case type (sporadic case or reported outbreak).
b P < .01.
c P < .05.