Table I.

Geometric mean Ab titers (log10) related to age and CHF groups and LDI vs no LDI subsetsa

A/New Cal (H1N1)A/Panama (H3N2)B/Hong Kong
0 wk4 wk10 wk0 wk4 wk10 wk0 wk4 wk10 wk
Young1.50 ± 0.53b2.07 ± 0.49b1.98 ± 0.46b1.78 ± 0.352.05 ± 0.452.02 ± 0.330.82 ± 0.251.27 ± 0.481.15 ± 0.41
Old0.99 ± 0.361.32 ± 0.431.25 ± 0.421.63 ± 0.462.00 ± 0.511.95 ± 0.480.89 ± 0.341.05 ± 0.451.01 ± 0.41
Old with LDI0.88 ± 0.400.94 ± 0.54c0.88 ± 0.27c1.54 ± 0.141.93 ± 0.502.66 ± 0.37d0.70 ± 0.080.70 ± 0.000.70 ± 0.00
CHF1.10 ± 0.441.49 ± 0.401.38 ± 0.521.76 ± 0.122.06 ± 0.481.87 ± 0.530.86 ± 0.341.19 ± 0.611.11 ± 0.53
CHF with LDI0.75 ± 0.080.92 ± 0.36c1.00 ± 0.43c1.65 ± 0.091.83 ± 0.152.51 ± 0.55d1.20 ± 0.631.19 ± 0.511.45 ± 0.58
  • a Ab titers by hemagglutination inhibition shown as geometric mean Ab titers (log10 GMT ± SD). Changes in hemagglutination inhibition titers from 0 to 4 wk reflect the response to influenza vaccination and from 4 to 10 wk the response to influenza infection. All groups, with or without CHF or LDI, had a significant increase in GMT in response to vaccination (p < 0.0001).

  • b GMT for the H1N1 strain are significantly higher in young compared to all older adult groups both pre- and postvaccination (p < 0.0001).

  • c GMT for the H1N1 strain are significantly lower in older adults who developed LDI vs older adults who did not (p = 0.003).

  • d GMT for the H3N2 strain increased significantly LDI subset at 10 wk postvaccination related to seroconversion to influenza infection (p = 0.0001).