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Table 2 Summary of immunogenicity for the per-protocol cohort

From: Immunogenicity and safety of quadrivalent versus trivalent inactivated influenza vaccine: a randomized, controlled trial in adults

Treatment groupa

Vaccine Strain

 

QIV

LD QIV-AS

LD TIV-AS

TIV

Nb

 

104

104

104

105

A/Solomon Islands

     

 GMT (95% CI)

Pre

21.4 (16.1–28.4)

22.2 (16.6–29.5)

23.3 (17.5–31.0)

18.4 (14.3–23.7)

 

Post

130.0 (106.1–159.4)

150.6 (118.4–191.5)

160.4 (129.1–199.3)

133.8 (105.6–169.7)

 SCR %(95% CI)

Post

56.7 (46.7–66.4)*$

57.7 (47.6–67.3)* $

54.8 (44.7–64.6)* $

60.0 (50.0–69.4)* $

 SPR %(95% CI)

Pre

37.5 (28.2–47.5)

42.3 (32.7–52.4)

40.4 (30.9–50.5)

35.2 (26.2–45.2)

 

Post

92.3 (85.4–96.6)* $

88.5 (80.7–93.9)* $

93.3 (86.6–97.3)* $

90.5 (83.2–95.3)* $

 SCF (95% CI)

Post

6.1 (4.6–8.0)*

6.8 (5.0–9.2)*

6.9 (5.0–9.4)*

7.3 (5.3–9.9)*

A/Wisconsin

     

 GMT (95% CI)

Pre

29.3 (23.0–37.3)

25.7 (19.8–33.3)

30.7 (23.7–39.8)

29.0 (22.5–37.4)

 

Post

162.1 (138.0–190.4)

189.5 (158.9–226.0)

197.9 (169.1–231.7)

156.3 (127.5–191.6)

 SCR %(95% CI)

Post

60.6 (50.5–70.0)* $

66.3 (56.4–75.3)* $

64.4 (54.4–73.6)* $

59.0 (49.0–68.5)* $

 SPR %(95% CI)

Pre

51.0 (41.0–60.9)

46.2 (36.3–56.2)

53.8 (43.8–63.7)

55.2 (45.2–65.0)

 

Post

97.1 (91.8–99.4)* $

98.1 (93.2–99.8)* $

100 (96.5–100)* $

96.2 (90.5–99.0)* $

 SCF (95% CI)

Post

5.5 (4.4–6.9)*

7.4 (5.8–9.4)*

6.4 (5.0–8.3)*

5.4 (4.1–7.0)*

B/Malaysia

     

 GMT (95% CI)

Pre

32.2 (24.8–41.8)

26.6 (20.2–35.0)

23.2 (17.7–30.4)

27.2 (20.6–35.8)

 

Post

192.8 (159.6–232.9)

213.0 (174.0–260.9)

187.0 (151.9–230.3)

188.5 (150.0–237.0)

 SCR %(95% CI)

Post

57.7 (47.6–67.3)* $

65.4 (55.4–74.4)* $

56.7 (46.7–66.4)* $

59.0 (49.0–68.5)* $

 SPR %(95% CI)

Pre

51.0 (41.0–60.9)

47.1 (37.2–57.2)

42.3 (32.7–52.4)

44.8 (35.0–54.8)

 

Post

97.1 (91.8–99.4)* $

97.1 (91.8–99.4)* $

96.2 (90.4–98.9)* $

93.3 (86.7–97.3)* $

 SCF (95% CI)

Post

6.0 (4.7–7.7)*

8.0 (6.1–10.5)*

8.1 (5.9–11.0)*

6.9 (5.2–9.3)*

B/Jiangsu

     

 GMT (95% CI)

Pre

19.6 (15.6–24.8)

19.5 (15.4–24.5)

23.4 (18.3–29.7)

19.2 (15.2–24.3)

 

Post

179.1 (151.4–211.9)

158.3 (130.7–191.9)

59.2 (47.3–74.0)

43.4 (34.5–54.6)

 SCR %(95% CI)

Post

76.0 (66.6–83.8)* $

78.8 (69.7–86.2)* $

26.9 (18.7–36.5)

19.0 (12.0–27.9)

 SPR %(95% CI)

Pre

31.7 (22.9–41.6)

38.5 (29.1–48.5)

43.3 (33.6–53.3)

39.0 (29.7–49.1)

 

Post

98.1 (93.2–99.8)* $

95.2 (89.1–98.4)* $

75.0 (65.6–83.0)*

63.8 (53.9–73.0)

 SCF (95% CI)

Post

9.1 (7.2–11.5)*

8.1 (6.6–10.0)*

2.5 (2.1–3.0)*

2.3 (1.9–2.6)

  1. a Groups were administered the quadrivalent influenza vaccine (QIV), the low-dose adjuvanted quadrivalent influenza vaccine (LD QIV-AS), the low-dose adjuvanted trivalent influenza vaccine (LD TIV-AS) or the trivalent influenza vaccine (TIV).
  2. b Abbreviations: 95% CI = 95% confidence interval (lower limit–upper limit); GMT = geometric mean titer; N = total number of participants; Pre = Pre-vaccination (Day 0); Post = Post-vaccination (Day 21); SCR = Seroconversion ratio defined as percentage of participants with antibody titer ≥1:40 1/DIL post-vaccination for initially seronegative participants, or ≥4 fold the pre-vaccination antibody titer for initially seropositive participants; SPR = Seroprotection rate defined as percentage of participants with antibody titer ≥1:40; SCF = Seroconversion factor defined as the fold increase in GMTs post-vaccination compared with pre-vaccination.
  3. * CHMP criteria were met or exceeded (SCR > 40%, SPR > 70%, SCF > 2.5).
  4. $ CBER criteria were met or exceeded (95% CI lower limit for SCR ≥ 40%, SPR ≥ 70%).