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. 2025 May 22;16:1569151. doi: 10.3389/fimmu.2025.1569151

Table 2.

Levels of total PT-IgG, and PT-IgG total relative avidity index, total absolute avidity, and fractional absolute avidity levels of very low to very high avidities in pregnant women at the time of delivery, and infants at the time of birth and at 2 months of age after vaccination during pregnancy with different formulations of recombinant pertussis vaccines or chemically detoxified pertussis vaccine.

  Pregnant women at delivery
ap1gen
(n=37)
Tdap1gen
(n=34)
Tdap2gen
(n=35)
TdaP5gen
(n=34)
Tdap8chem
(n=35)
P-value
PT-IgG, IU/mL
GMC (95% CI)
46.88
(29.44-74.66)
33.85
(24.65-46.48)
50.96
(35.05-74.07)
85.06
(61.70-117.25)
39.58
(29.47-53.17)
0.0018
Total RAI, AU
Mean (SD)
113.09
(36.48)
114.82
(25.08)
116.36
(31.45)
131.25
(21.96)
120.20
(27.40)
0.0468
Total absolute avidity, AAU/mL
GMC (95% CI)
47.62
(25.65-88.42)
37.38
(24.96-55.99)
56.31
(35.18-90.15)
109.72
(77.49-155.34)
45.64
(30.90-67.42)
0.0009
F absolute avidity, IU/mL
GMC (95% CI)
Very low (<0.25 M)
Low (0.25 M)
Low-medium (0.5 M)
Medium (1.0 M)
Medium-high (1.5 M)
High (2.0 M)
Very high (3.0 M)
4.21 (2.47-7.16)
2.59 (1.44-4.67)
5.69 (3.12-10.36)
5.68 (3.03-10.64)
7.29 (3.91-13.59)
6.91 (3.24-14.74)
2.69 (1.37-5.30)
3.58 (2.48-5.17)
1.75 (1.03-2.98)
4.90 (3.31-7.27)
5.37 (3.62-7.97)
5.06 (3.37-7.58)
5.34 (2.92-9.76)
1.26 (0.75-2.11)
4.62 (3.11-6.86)
3.57 (2.55-5.00)
8.18 (5.07-13.18)
6.18 (3.69-10.35)
5.97 (3.45-10.35)
9.19 (5.06-16.67)
2.81 (1.59-4.96)
7.19 (5.25-9.85)
4.08 (2.53-6.58)
12.67 (8.68-18.51)
12.66 (8.68-18.46)
11.20 (7.42-16.91)
19.60 (13.42-28.63)
7.43 (4.68-11.77)
3.68 (2.59-5.22)
2.46 (1.66-3.64)
6.74 (4.70-9.66)
5.35 (3.65-7.84)
5.96 (4.21-8.44)
6.40 (3.66-11.19)
2.21(1.27-3.85)
0.0446
0.0818
0.0314
0.0019
0.0087
0.0020
0.0011
Infants at the time of birth
ap1gen
(n=37)
Tdap1gen
(n=34)
Tdap2gen
(n=35)
TdaP5gen
(n=34)
Tdap8chem
(n=35)
P-value
PT-IgG, IU/mL
GMC (95% CI)
67.39
(42.77-106.19)
46.33
(33.72-63.65)
72.10
(50.45-103.06)
120.17
(88.85-162.52)
51.58
(38.30-69.47)
0.0010
Total RAI, AU
Mean (SD)
115.00
(37.91)
116.40
(24.16)
121.40
(27.21)
126.53
(18.46)
124.65
(29.02)
0.4630
Total absolute avidity, AAU/mL
GMC (95% CI)
70.23
(38.67-127.57)
51.92
(34.46-78.23)
84.61
(55.10-129.94)
150.31
(109.38-206.55)
61.58
(41.42-91.55)
0.0014
F absolute avidity, IU/mL
GMC (95% CI)
Very low (<0.25 M)
Low (0.25 M)
Low-medium (0.5 M)
Medium (1.0 M)
Medium-high (1.5 M)
High (2.0 M)
Very high (3.0 M)
4.85 (2.74-8.58)
3.84 (2.09-7.06)
9.61 (5.37-17.19)
7.67 (4.31-13.63)
6.88 (3.68-12.86)
12.28 (6.00-25.14)
4.51 (2.37-8.60)
5.33 (3.76-7.57)
2.43 (1.56-3.79)
6.87 (4.30-10.96)
6.93 (4.73-10.17)
5.78 (3.61-9.24)
9.05 (5.35-15.30)
2.17 (1.29-3.66)
7.43 (5.56-9.92)
4.68 (3.12-7.03)
10.26 (7.02-15.01)
9.00 (5.59-14.49)
11.22 (6.89-18.28)
13.22 (7.81-22.36)
4.50 (2.54-7.97)
11.18 (7.69-16.27)
7.33 (4.89-10.99)
18.72 (13.82-25.34)
16.47 (11.96-22.68)
18.29 (12.67-26.42)
27.57 (18.98-40.05)
9.32 (6.17-14.06)
4.39 (3.04-6.33)
3.73 (2.62-5.32)
7.31 (4.98-10.73)
6.98 (4.78-10.18)
7.28 (4.91-10.80)
9.67 (5.87-15.95)
3.69 (2.14-6.34)
0.0092
0.0332
0.0015
0.0167
0.0009
0.0006
0.0037
Infants at 2 months of age
ap1gen
(n=37)
Tdap1gen
(n=34)
Tdap2gen
(n=35)
TdaP5gen
(n=33)
Tdap8chem
(n=34)
P-value
PT-IgG, IU/mL
GMC (95% CI)
24.96
(17.55-35.49)
13.63
(10.01-18.55)
20.95
(15.08-29.10)
33.34
(24.30-45.74)
15.30
(11.09-21.10)
0.0012
Total RAI, AU
Mean (SD)
82.98
(33.43)
76.57
(34.79)
91.53
(37.57)
108.73
(21.46)
78.88
(38.81)
0.0011
Total absolute avidity, AAU/mL
GMC (95% CI)
18.42
(11.02-30.79)
9.05
(5.56-14.74)
16.87
(10.29-27.67)
35.04
(23.97-51.23)
10.29
(6.13-17.26)
0.0010
F absolute avidity, IU/mL
GMC (95% CI)
Very low (<0.25 M)
Low (0.25 M)
Low-medium (0.5 M)
Medium (1.0 M)
Medium-high (1.5 M)
High (2.0 M)
Very high (3.0 M)
3.35 (2.08-5.40)
1.87 (1.07-3.25)
3.86 (2.29-6.50)
2.57 (1.41-4.68)
1.85 (1.01-3.38)
1.90 (0.96-3.78)
0.73 (0.47-1.14)
1.84 (1.09-3.11)
0.68 (0.40-1.16)
2.03 (1.15-3.59)
1.23 (0.67-2.25)
1.03 (0.56-1.90)
0.67 (0.36-1.23)
0.37 (0.25-0.55)
2.72 (1.73-4.29)
0.96 (0.59-1.57)
2.87 (1.71-4.84)
2.07 (1.18-3.65)
2.17 (1.22-3.88)
1.76 (0.91-3.42)
0.64 (0.40-1.03)
3.84 (2.77-5.32)
1.97 (1.25-3.10)
5.19 (3.60-7.48)
4.87 (3.30-7.18)
5.73 (4.08-8.06)
4.78 (2.69-8.48)
1.11 (0.68-1.81)
1.89 (1.13-3.18)
1.09 (0.66-1.81)
1.91 (1.06-3.47)
1.22 (0.67-2.25)
1.04 (0.56-1.95)
0.95 (0.49-1.83)
0.43 (0.29-0.64)
0.0547
0.0124
0.0550
0.0125
0.0003
0.0005
0.0024

RAI, relative avidity index; F, Fractional; SD, standard deviation; AU, Avidity Unit; AAU/mL, Absolute Avidity Unit/mL; ap1gen, acellular-pertussis vaccine containing 1 µg of pertussis toxin genetically detoxified (PTgen); Tdap1gen, tetanus, reduced-dose diphtheria [Td] combined with ap1gen; Tdap2gen, Td combined with 2 µg PTgen; TdaP5gen, Td combined with 5 µg PTgen; Tdap8chem Td combined with 8 µg of pertussis toxin chemically-detoxified; PT, Pertussis toxin; IgG, immunoglobulin G; IU, international unit; GMC, Geometric mean concentration; CI, Confidence interval. P-values are based on comparison of outcomes for all vaccine groups using Kruskal-Wallis Test. A p-value of ≤ 0.05 is considered statistically significant.