Table 1. Dynamic Changes of the Hemagglutination-Inhibition Titers against the 2009 A/H1N1 Virus after Administration of the 2009 A/H1N1 Influenza Vaccine.
| Time | Seroprotection rate -% (95% CI) | Seroconversion rate - % (95% CI) | GMT (95% CI) |
| Pre (N = 58) | 12 (5-23) | - | 16 (13-20) |
| day 3 (N = 58) | 19 (10-31) | 5 (1-14) | 19 (15-24) |
| day 5 (N = 58) | 47 (33-60)** | 19 (10-31)* | 32 (27-38)** |
| day 10 (N = 58) | 93 (83-98)** | 72 (59-83)** | 86 (68-108)** |
| day 14 (N = 58) | 97 (88-100)** | 86 (75-94)** | 112 (88-142)** |
| day 21 (N = 58) | 97 (88-100)** | 86 (75-94)** | 113 (89-144)** |
| day 30 (N = 51) | 98 (90-100)** | 88 (76-96)** | 117 (92-149)** |
| day 45 (N = 55) | 95 (85-99)** | 84 (71-92)** | 117 (91-150)** |
| day 60 (N = 56) | 95 (85-99)** | 84 (72-92)** | 113 (88-145)** |
Seroprotection is defined as HI titer of 1∶40 or more. Seroconversion is defined as postvaccination HI titer of 1∶40 or more, increasing at least four times. GMT = geometric mean titer. HI titers below 1∶10 were assigned a value of 1∶5, in calculating the geometric mean titer.
*(p<0.05) and
**(p<0.001) represent the statistical significances compared with the pre-vaccination values (day 3 value for seroconversion rate). The Pearson's chi-squared test was used for the seroprotection and seroconversion rate analysis, the two-way Student's t-test for the GMT analysis. Pre: pre-vaccination.