Table 1. Relation of amino acid changes in the hemagglutinin to clinical outcome.
| Clinical outcomea | ||||
| Genotype of HA position | Mild | Severe or fatal | All cases | P-valuec |
| 222 D | 86.5% (96/111) | 82.6% (19/23) | 85.8% (115/134) | p = 0.742 |
| 222 G | 0% (0/111) | 8.7% (2/23) | 1.5% (2/134) | p = 0.028 |
| 222 Y | 0% (0/111) | 4.3% (1/23) | 0.7% (1/134) | p = 0.172 |
| 222 E | 13.5% (15/111) | 4.3% (1/23) | 11.9% (16/134) | p = 0.305 |
| 293 Q | 97.3% (108/111) | 100% (23/23) | 97.8% (131/134) | |
| 293 H | 2.7% (3/111) | 0% (0/23) | 2.2% (3/134) | p = 1 |
| 321 I | 17.1% (19/111) | 34.8% (8/23) | 20.1% (27/134) | |
| 321 V | 82.9% (92/111) | 65.2% (15/23) | 79.9% (107/134) | p = 0.083 |
| 374 E | 98.1% (102/104) | 95.5% (21/22) | 97.6% (123/126b) | |
| 374 K | 1.9% (2/104) | 4.5% (1/22) | 2.4% (3/126b) | p = 0.441 |
a
Percentage and number of patients of each genotype are presented in both clinical categories.
b
The entire hemagglutinin sequence (HA2 portion) was not available from all patients.
c
The statistical significance between the number of mild and severe cases was calculated by the Fisher's exact test.