TABLE 2

Geometric mean and mean fold rise

Vaccine antigen and categoryNo. (%) of subjectsMean age (yr)GMTaMFRb
S0S1S2S1/S0S2/S1S2/S0
A/New Caledonia/20/99(H1N1)
    Entire sample259 (100)1.5723463.32.06.6
    Prevaccination titer
        <1:10200 (77)1.2c5d15d36d3.0d,e2.4d,e7.1d,e
        1:10–1:2044 (17)2.41584945.7e1.16.4e
        ≥1:4015 (6)2.6661531762.3e1.12.6e
    Age
        0 yr64 (25)0.7c5d6d21d1.2d,e3.3d,e4.0d,e
        1 yr65 (25)1.4514392.7e2.7e7.3e
        2 yr64 (25)2.4858807.4e1.4e10.3e
        3 yr66 (25)3.41154705.0e1.3e6.4e
    Influenza vaccination in the past 3 yr
        Unvaccinated144 (56)0.9c5d9d32d1.8d,e3.5d,e6.1e
        Vaccinated114 (44)2.31073727.4e1.07.3e
    Influenza-like illness during the last season
        Absent136 (53)1.2c716d37d2.2d,e2.3d,e5.2d,e
        Present122 (47)1.9735595.1e1.7e8.7e
A/New York/55/2004(H3N2)
    Entire sample259 (100)1337712.82.05.5
    Prevaccination titer
        <1:10187 (72)1.2c5d12d29d2.3d,e2.5d,e5.9d,e
        1:10–1:209 (4)2.11523529616.01.320.2
        ≥1:4063 (24)2.32088528064.1e0.93.9e
    Age
        0 yr6d8d32d1.4d,e4.1d,e5.5e
        1 yr820512.4e2.5e6.1e
        2 yr221081305.0e1.2e6.0e
        3 yr271051234.0e1.2e4.6e
    Influenza vaccination in the past 3 yr
        Unvaccinated9d17d53d1.9d,e3.1d,e5.9e
        Vaccinated20971054.8e1.15.2e
    Influenza-like illness during the last season
        Absent10d23d54d2.4d,e2.3d,e5.6e
        Present1861963.5e1.6e5.5e
B/Shanghai/361/2002
    Entire sample259 (100)822342.81.64.4
    Prevaccination titer
        <1:10188 (73)1.3c5d10d19d2.0d,e1.9d,e3.7d,e
        1:10–1:2040 (15)2.2131261219.5e1.09.2e
        ≥1:4031 (12)2.2652742744.2e1.04.2e
    Age
        0 yr5d6d13d1.1d2.3d,e2.5d,e
        1 yr720322.7e1.6e4.4e
        2 yr840524.9e1.3e6.3e
        3 yr1250624.2e1.25.1e
    Influenza vaccination in the past 3 yr
        Unvaccinated6d11d23d1.7d,e2.2d,e3.8d,e
        Vaccinated1155565.1e1.05.2e
    Influenza-like illness during the last season
        Absent7d14d24d2.0d,e1.8d,e3.6d,e
        Present938514.1e1.3e5.5e
  • a GMT, geometric mean titer.

  • b MFR, mean fold rise.

  • c P < 0.05 by t test or ANOVA.

  • d P < 0.05 by the Wilcoxon rank sum test or Kruskal-Wallis rank test for intercategory comparisons.

  • e P < 0.05 by the Wilcoxon signed-rank test for intracategory comparisons.