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Table 5 Hemagglutination-inhibition antibody responses after TIV according to previous seasonal influenza vaccination history 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

Previous vaccination†

Time point

SPR

SCR

MGI

n/N (%; 95% CI)

n/N (%; 95% CI)

N; value (95% CI)

18–60 years

>60 years

18–60 years

>60 years

18–60 years

>60 years

A/H1N1

Yes

Day 0

13/20

19/44

(65.0; 40.8–84.6)

(43.2; 28.3–59.0)

  

Day 21

20/20

41/44

13/20

31/44

20; 7.1

44; 6.8

(100; 83.2–100)

(93.2; 81.3–98.6)

(65.0; 40.8–84.6)

(70.5; 54.8–83.2)

(3.5– 14.3)

(4.7–9.8)

 

No

Day 0

16/29

3/26

(55.2; 35.7–73.6)

(11.5; 2.4–30.2)

  

Day 21

29/29

21/26

22/29

19/26

29; 12.6

26; 16.0

(100; 88.1–100)

(80.8; 60.6–93.4)

(75.9; 56.5–89.7)

(73.1; 52.2–88.4)

(6.8– 23.3)

(9.4–27.3)

A/H3N2

Yes

Day 0

8/20

15/44

(40.0; 19.1–63.9)

(34.1; 20.5–49.9)

  

Day 21

20/20

43/44

15/20

35/44

20; 8.9

44; 9.9

(100; 83.2–100)

(97.7; 88.0–99.9)

(75.0; 50.9–91.3)

(79.5; 64.7–90.2)

(4.7– 16.8)

(6.7–14.7)

 

No

Day 0

7/29

2/26

(24.1; 10.3–43.5)

(7.7; 0.9–25.1)

  

Day 21

28/29

22/26

26/29

22/26

29; 17.2

26; 25.8

(96.6; 82.2–99.9)

(84.6; 65.1–95.6)

(89.7; 72.6–97.8)

(84.6; 65.1–95.6)

(11.8–25.1)

(15.7–42.5)

B strain (Victoria)

Yes

Day 0

12/20

27/44

  

(60.0; 36.1–80.9)

(61.4; 45.5–75.6)

  

Day 21

20/20

44/44

10/20

27/44

20; 5.3

44; 5.0

(100; 83.2–100)

(100; 92.0–100)

(50.0; 27.2–72.8)

(61.4; 45.5–75.6)

(2.7– 10.4)

(3.5–7.0)

 

No

Day 0

9/29

8/26

  

(31.0; 15.3–50.8)

(30.8; 14.3–51.8)

  

Day 21

27/29

25/26

23/29

24/26

29; 19.6

26; 23.9

(93.1; 77.2–99.2)

(96.2; 80.4–99.9)

(79.3; 60.3–92.0)

(92.3; 74.9–99.1)

(10.3– 37.2)

(14.0–40.6)

  1. †Received (yes) or did not receive (no) seasonal influenza vaccine during the preceding 3 seasons (2009–2010, 2008–2009, 2007–2008); n/N, number fulfilling definition of response/total number in group; TIV, inactivated trivalent influenza vaccine; SCR, seroconversion rate defined as the proportion with antibody titer <1:10 at baseline and with post-vaccination titer of ≥1:40, or pre-vaccination titer of ≥1:10 and a ≥4-fold post-vaccination increase in titer; SPR, seroprotection rate defined as proportion with post-vaccination titer ≥1:40; MGI, mean geometric increase defined as the geometric mean of the ratio between pre-vaccination and post-vaccination reciprocal titers; Immune responses were assessed according to the to the European Union Committee for Medicinal Products for Human Use (CHMP) licensure criteria: to fulfil the criteria the point estimates for SCR needed to be >40%, for SPR >70%, and MGI >2.5 in the 18–60 years group, and SCR >30%, for SPR >60%, and MGI >2.0 in the >60 years group [21].