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Table 4 Hemagglutination-inhibition antibody responses after TIV in the per-protocol immunogenicity cohort

From: A historically-controlled Phase III study in adults to characterize the acceptability of a process change for manufacturing inactivated quadrivalent influenza vaccine

Strain Time point Seropositive GMT MGI
n (%; 95% CI) value (95% CI) value (95% CI)
18–60 years >60 years 18–60 years >60 years 18–60 years >60 years
N = 49 N = 70 N = 49 N = 70 N = 49 N = 70
A/H1N1 Day 0 35 37 39.2 15.2
(71.4; 56.7–83.4) (52.9; 40.6–64.9) (24.0–63.8) (11.1–21.0)
Day 21 49 70 390.1 142.1 10.0 (6.3–15.7) 9.3 (6.8–12.8)
(100; 92.7–100) (100; 94.9–100) (293.8–518.1) (105.1–192.0)
A/H3N2 Day 0 26 38 14.1 13.0
(53.1; 38.3–67.5) (54.3; 41.9–66.3) (10.1–19.8) (9.8–17.3)
Day 21 49 70 185.6 183.7 13.1 (9.3–18.5) 14.1 (10.2–19.5)
(100; 92.7–100) (100; 94.9–100) (140.9–244.5) (139.6–241.8)
B strain (Victoria) Day 0 34 58 22.7 28.0
(69.4; 54.6–81.7) (82.9; 72.0–90.8) (15.2–34.0) (21.5–36.5)
Day 21 48 69 260.6 248.6 11.5 (7.0–18.7) 8.9 (6.3–12.4)
(98.0; 89.1–99.9) (98.6; 92.3–100) (184.6–368.0) (185.9–332.3)
  1. TIV, inactivated trivalent influenza vaccine; Seropositive, titer ≥1:10; GMT, geometric mean titer; MGI, mean geometric increase defined as the geometric mean of the ratio between pre-vaccination and post-vaccination reciprocal titers.