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Table 3 Hemagglutination-inhibition antibody responses after QIV 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†

Timepoint

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

N = 28

N = 28

N = 28

N = 28

N = 28

N = 28

A/H1N1

Yes

Day 0

25/28

16/28

–

–

–

–

(89.3; 71.8–97.7)

(57.1; 37.2–75.5)

  

Day 21

28/28

25/28

10/28

9/28

28; 3.1

28; 3.5

(100; 87.7–100)

(89.3; 71.8–97.7)

(35.7; 18.6–55.9)

(32.1; 15.9–52.4)

(2.0–4.9)

(2.3–5.2)

 

No

Day 0

19/28

10/28

–

–

–

–

(67.9; 47.6–84.1)

(35.7; 18.6–55.9)

  

Day 21

27/28

27/28

18/28

25/28

28; 7.4

28; 22.9

(96.4; 81.7–99.9)

(96.4; 81.7–99.9)

(64.3; 44.1–81.4)

(89.3; 71.8–97.7)

(4.1–13.3)

(12.7–41.2)

A/H3N2

Yes

Day 0

21/28

19/28

–

–

–

–

(75.0; 55.1–89.3)

(67.9; 47.6–84.1)

  

Day 21

27/28

26/28

9/28

13/28

28; 2.7

28; 3.4

(96.4; 81.7–99.9)

(92.9; 76.5–99.1)

(32.1; 15.9–52.4)

(46.4; 27.5–66.1)

(2.0–3.6)

(2.5–4.7)

 

No

Day 0

13/28

9/28

–

–

–

–

(46.4; 27.5–66.1)

(32.1; 15.9–52.4)

  

Day 21

27/28

27/28

18/28

22/28

28; 8.5

28; 13.8

(96.4; 81.7–99.9)

(96.4; 81.7–99.9)

(64.3; 44.1–81.4)

(78.6; 59.0–91.7

(5.2–13.9)

(7.4–25.6)

B strain (Victoria)

Yes

Day 0

26/28

17/28

–

–

–

–

(92.9; 76.5–99.1)

(60.7; 40.6–78.5)

  

Day 21

28/28

27/28

4/28

12/28

28; 2.4

28; 3.3

(100; 87.7–100)

(96.4; 81.7–99.9)

(14.3; 4.0–32.7)

(42.9; 24.5–62.8)

(1.7–3.3)

(2.3–4.9)

 

No

Day 0

21/28

14/28

–

–

–

–

(75.0; 55.1–89.3)

(50.0; 30.6–69.4)

  

Day 21

28/28

28/28

15/28

21/28

28; 4.9

28; 11.5

(100; 87.7–100)

(100; 87.7–100)

(53.6; 33.9–72.5)

(75.0; 55.1–89.3)

(3.0–7.9)

(6.8–19.2)

B strain (Yamagata)

Yes

Day 0

27/28

24/28

–

–

–

–

(96.4; 81.7–99.9)

(85.7; 67.3–96.0)

  

Day 21

28/28

28/28

6/28

12/28

28; 2.1

28; 4.1

(100; 87.7–100)

(100; 87.7–100)

(21.4; 8.3–41.0)

(42.9; 24.5–62.8)

(1.6–2.7)

(2.6–6.5)

 

No

Day 0

21/28

21/28

–

–

–

–

(75.0; 55.1–89.3)

(75.0; 55.1–89.3)

  

Day 21

28/28

28/28

14/28

23/28

28; 4.6

28; 9.4

(100; 87.7–100)

(100; 87.7–100)

(50.0; 30.6–69.4)

(82.1; 63.1–93.9)

(3.1–6.9)

(6.4–13.8)

  1. †Received (yes) or did not receive (no) seasonal influenza vaccine during the preceding season (2010–2011); QIV, inactivated quadrivalent influenza vaccine; n/N, number fulfilling definition of response/total number in group; 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].
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BMC Infectious Diseases

ISSN: 1471-2334

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