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. 2011 Sep 6;6(9):e24384. doi: 10.1371/journal.pone.0024384

Table 2. Absolute percentages of subjects who did not achieve seroconversion * after the first dose of H1N1 influenza vaccination and who achieved seroconversion after the second dose, according to vaccine dose (in µg of Hemagglutinin antigen) and formulation (presence or absence of an adjuvant).

Adults 1 Elderly 2 Adolescents 3 Children 4 All ages
Formulations** % (95%CI) N (ref) % (95%CI) N (ref) % (95%CI) N (ref) % (95%CI) N (ref) % (95%CI)
Non-adjuvanted
7.5×2 vs 7.5×1 All *** 8 (6–11) 465 [12], [19], [25] 8 (4–12) 170 [19], [25] 3 (1–6) 195 [19] 36 (24–49) 501 [19], [21], [27], [28] 22 (10–38)
15×2 vs 15×1 (All split-virus) 6 (2–9) 1504 [11], [12], [15], [18], [19], [39] 5 (0–14) 871 (10, 16–18) 4 (1–7) 1151 [8], [19], [21], [27], [54] 23 (15–31) 1556 [8], [19], [21], [26], [27], [28], [54] 11 (6–17)
30×2 vs 30×1 (All split-virus) 2 (0–6) 1147 [11], [15], [18], [19] 4 (0–8) 716 [11], 2 (0–3) 769 [8], [19], [54] 9 (4–17) 969 [8], [19], [26], [54] 3 (1–6)
Adjuvanted
≤6×2 vs ≤6×1 All 5 (3–7) 597 [12], [16], [19], [25], [30], [31], [39] 18 (11–26) 104 [25], [31] 38 (22–56) 29 [37] 19 (4–49) 175 [9], [37] 7 (3–13)
- Aluminum 4 (1–10) $ 98 [19] 0 0 0 4 (1–10)
- Other adjuvants 5 (2–8) 499 18 (11–26) 104 38 (22–56) 29 19 (4–49) 175 8 (3–15)
7.5×2 vs 7.5×1 All 14 (4–27) 224 [12], [19] 29 (20–39) 103 [19], [38] 8 (1–21) 266 [8], [19], [37], [54] 20 (3–46) 271 [8], [19], [37], [54] 13 (2–31)
- Aluminum 9 (6–14) 200 [19] 29 (20–39) 103 9 (5–14) 192 [19] 37 (30–44) 195 [19] 20 (17–23)
- Other adjuvants 21 (7–42) 24 0 7 (2–39) 74 12 (0–38) 76 11 (0–38)
15×2 vs 15×1 (All aluminum) 12 (8–18) 196 [19] 10 (5–18) 101 [19] 6 (3–9) 183 [19] 24 (19–31) 194 [19] 13 (11–16)

Data from single studies have been combined using proportion meta-analysis (random-effect model). Non randomized and randomized trials were included.

N  =  total number of subject analyzed; (ref)  =  References to included studies; CI  =  Confidence Intervals;

1

Adults  =  from 18 to 64 years;

2

Elderly  =  from 65 years;

3

Adolescents  =  from 10 to 17 years;

4

Children  =  from 6 months to 9 years (see Table S1 for several exceptions).

*Seroconversion  =  subjects with a pre-vaccination hemagglutinination-inhibition antibody titer < = 1∶10 and a post-vaccination titer > = 1∶40, or a pre-vaccination titer > = 1∶10 and an increase in the titer by a factor of four or more after vaccination.

**7.5×1  =  Results collected after the first or single dose of 7.5 µg; 7.5×2  =  Results collected after the second dose of 7.5 µg.

***All split-virus except 133 adults and 33 elderly subjects receiving whole-virus, with similar results [25].

$

Whole-virus only.