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Table 1 Immune response for haemagglutination-inhibition (HI) antibodies against A/California/7/2009 H1N1 in adults aged 18 to 60 years and in adults >60 years (per-protocol immunogenicity cohorts)

From: Flexibility of interval between vaccinations with AS03A-adjuvanted influenza A (H1N1) 2009 vaccine in adults aged 18–60 and >60 years: a randomized trial

 

N

Seroprotection rate (titre ≥ 1:40) % (95% CI)

Seroconversion rate* % (95% CI)

Geometric Mean Fold Rise** (95% CI)

N

Seroprotection rate (titre ≥ 1:40) % (95% CI)

Seroconversion rate* % (95% CI)

Geometric Mean Fold Rise** (95% CI)

  

Vaccinated on Day 0 (subjects from Groups A and B pooled) 18–60 years

 

Vaccinated on Day 0 (subjects from Groups A and B pooled) 18>60 years

Day 0 (Prevaccination)

160

14.4

-

-

136

5.1

-

-

(9.3-20.8)

   

(2.1-10.3)

  

Day 21

160

97.5

96.3

45.0

136

91.9

89.0

23.4

(93.7-99.3)

(92.0-98.6)

(37.3-54.5)

 

(86.0-95.9)

(82.5-93.7)

(19.1-28.7)

 

Group A Vaccinated on Day 0 and Day 21 18–60 years

Group A Vaccinated on Day 0 and Day 21 >60 years

Day 0 (Prevaccination)

87

12.6

-

-

83

7.2

-

-

(6.5-21.5)

 

-

 

(2.7-15.1)

  

Day 21

87

100

100

51.6

83

90.4

89.2

23.0

(95.8-100)

(95.8-100)

(40.7-65.5)

 

(81.9-95.7)

(80.4-94.9)

(17.7-29.9)

Day 42

87

100

98.9

86.7

83

100

98.8

54.9

(95.8-100)

(93.8-100)

(68.6-109.5)

 

(95.7-100)

(93.5-100)

(43.4-69.3)

Day 182

85

97.6

92.9

26.6

83

90.4

86.7

13.4

(91.8-99.7)

(85.3-97.4)

(20.8-34.0)

 

(81.9-95.7)

(77.5-93.2)

(10.9-16.5)

Day 203

 

-

-

-

 

-

-

-

Day 364

79

82.3

75.9

11.0

76

50.0

40.8

4.8

(72.1-90.0)

(65.0-84.9)

(9.2-15.5)

 

(38.3-61.7)

(29.6-52.7)

(3.8-6.1)

 

Group B Vaccinated on Day 0 and Day 182 18–60 years

Group B Vaccinated on Day 0 and Day 182 >60 years

Day 0 (Prevaccination

67

14.9 (7.4-25.7)

-

-

48

2.1 (0.1-11.1)

-

-

Day 21

67

94.0

92.5

39.2

48

95.8

89.6

23.3

(85.4-98.3)

(83.4-97.5)

(28.3-54.2)

 

(85.7-99.5)

(77.3-96.5)

(16.6-32.7)

Day 42

67

95.5

91.0

31.9

48

89.6

81.3

16.5

(87.5-99.1)

(81.5-96.6)

(23.4-43.4)

 

(77.3-96.5)

(67.4-91.1)

(11.8-23.0)

Day 182

56

85.7

83.9

14.6

30

63.3

56.7

6.1

(73.8-93.6)

(71.7-92.4)

(10.8-19.7)

 

(43.9-80.1)

(37.4-74.5)

(3.9-9.4)

Day 203

48

100

100

79.0

28

100

100

65.7

(92.6-100)

(92.6-100)

(58.0-107.7)

 

(87.7-100)

(87.7-100)

(41.4-104.1)

Day 364

60

93.3

90.0

17.3

46

80.4

73.9

8.3

(83.8-98.2)

(79.5-96.2)

(13.0-23.0)

 

(66.1-90.6)

(58.9-85.7)

(6.0-11.3)

  1. *Seroconversion rate for haemagglutination-inhibition antibody response is defined as the percentage of vaccinees who have a prevaccination titre <1:10 and a post-vaccination titre ≥1:40, or a significant increase in antibody titre defined as the percentage of vaccinees who have a pre-vaccination titre ≥ 1:10 and at least a fourfold increase in post-vaccination titre. **Geometric mean fold rise is defined as geometric mean of the within-subject ratios of the post-vaccination reciprocal haemagglutination-inhibition titre to the Day 0 reciprocal agglutination-inhibition titre.
  2. European Medicines Agency Committee for Medicinal Products for Human Use (CHMP) criteria for haemagglutination-inhibition antibody response in 18–60 year olds are: seroprotection rate >70%, seroconversion rate >40%, and geometric mean fold rise >2·5 and in adults >60 years are seroprotection rate >60%, seroconversion rate >30%, and geometric mean fold rise >2·0.
  3. United States Center for Biologics Evaluation and Research (CBER) criteria for hemagglutination-inhibition antibody response in adults <65 years are: lower limit (LL) of 95% CI for seroprotection ≥70% and LL of 95% CI for seroconversion ≥40% and in adults ≥65 years are LL of 95% CI for seroprotection ≥60% and LL of 95% CI for seroconversion ≥30%.
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BMC Infectious Diseases

ISSN: 1471-2334

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