TABLE 3

Odds ratios for seroresponse and seroprotection proportions after the first vaccinationf

Vaccine antigen and categorySeroresponse (S1/S0 ≥ 4)Seroprotection (S1 ≥ 1:40)
Total no. of subjectsNo. (%) with seroresponseOR (95% CI)aTotal no. of subjectsNo. (%) with seroprotectionOR (95% CI)a
CrudeAdjustedbCrudeAdjustedb
A/New Caledonia/20/99(H1N1)
    Prevaccination titer
        <1:1020090 (45)1.01.020065 (33)1.01.0
        1:10–1:204438 (86)7.7 (3.1, 19.1)2.2 (0.8, 5.8)4442 (95)43.6 (10.2, 186)5.4 (2.1, 13.6)
        ≥1:40155 (33)0.6 (0.2, 1.9)0.14 (0.04, 0.49)
        Ptrendc
    Age
        0 yr646 (9)0.01 (0.01, 0.08)0.03 (0.01, 0.07)632 (3)0.01 (0.003, 0.05)0.03 (0.01, 0.1)
        1 yr6526 (40)0.2 (0.1, 0.4)0.17 (0.08, 0.34)6518 (28)0.13 (0.06, 0.25)0.2 (0.1, 0.4)
        2–3 yr130101 (78)1.01.011687 (75)1.01.0
        Ptrenddddd
A/New York/55/2004 (H3N2)
    Prevaccination titer
        <1:1018763 (34)1.01.018741 (22)1.01.0
        1:10–1:2098 (89)15.8 (1.9, 129)8.8 (1.1, 73.1)98 (89)28.5 (3.5, 234)16.3 (1.8, 148)
        ≥1:406339 (62)3.2 (1.8, 5.8)1.7 (0.9, 3.3)
        Ptrendd
    Age
        0 yr647 (11)0.08 (0.04, 0.19)0.11 (0.04, 0.26)620NANA
        1 yr6529 (45)0.4 (0.2, 0.8)0.5 (0.3, 0.9)569 (16)0.18 (0.08, 0.42)0.18 (0.08, 0.44)
        2–3 yr13078 (60)1.01.07840 (51)1.01.0
        Ptrenddd
B/Shanghai/361/2002
    Prevaccination titer
        <1:1018859 (31)1.01.018839 (21)1.01.0
        1:10–1:204034 (85)12.4 (4.9, 31.1)9.2 (3.2, 26.6)4037 (93)47.1 (13.8, 161)47.5 (11.5, 197)
        ≥1:403118 (58)3.0 (1.4, 6.6)1.5 (0.7, 3.4)
        Ptrendde
    Age
        0 yr643 (5)0.03 (0.01, 0.09)0.03 (0.01, 0.11)643 (5)0.04 (0.01, 0.14)0.04 (0.01, 0.17)
        1 yr6523 (35)0.3 (0.2, 0.5)0.4 (0.2, 0.7)6523 (35)0.3 (0.1, 0.5)0.3 (0.1, 0.8)
        2–3 yr13085 (65)1.01.013085 (65)1.01.0
        Ptrenddddd
  • a OR, odds ratio; CI, confidence interval.

  • b Adjusted for prevaccination titer and age.

  • c P < 0.05.

  • d P < 0.001.

  • e P < 0.01.

  • f Subjects with prevaccination titer of ≥1:40 were excluded from the seroprotection analyses.