Volume 17, Number 3—March 2011
Research
Swine Influenza Virus Antibodies in Humans, Western Europe, 2009
Table 3
Virus (strain) and cutoff value | Swine workers, no. (%; 95% CI), n = 211 | Controls, no. (%; 95% CI), n = 224 | p value |
---|---|---|---|
Pandemic (H1N1) 2009 (A/Luxembourg/43/2009) | |||
>10 | 46 (21.8; 16.8–27.9)† | 23 (10.3); 6.9–14.9)‡ | 0.001§ |
>20 | 37 (17.5; 13–23.2)† | 16 (7.1; 4.4–11.3)‡ | 0.001§ |
>40 | 31 (14.7; 10.6–20.1) | 12 (5.4; 3.1–9.1) | 0.002§ |
>80 | 14 (6.6; 4–10.8) | 4 (1.8; 0.7–4.5) | 0.02§ |
>160 | 6 (2.8; 1.3–6.06) | 0 (0; 0–1.2) | 0.033¶ |
>320 |
5 (2.4; 1–5.4) |
0 (0; 0–1.2) |
0.061¶ |
Avian-like SIV (H1N1) (A/swine/Belgium/1/98) | |||
>10 | 66 (31.3) 25.4–37.8) | 59 (26.3; 21–32.5) | 0.289§ |
>20 | 57 (27; 21.5–33.4) | 38 (17; 12.6–22.4) | 0.015§ |
>40 | 39 (18.5; 13.8–24.3) | 12 (5.4; 3.1–9.1) | <0.001§ |
>80 | 21 (10; 6.6–14.7) | 4 (1.8; 0.7–4.5) | <0.001§ |
>160 | 9 (4.3; 2.3–7.9) | 1 (0.4; 0.1–2.5) | 0.019¶ |
>320 |
4 (1.9; 0.7–4.8) |
1 (0.4; 0.1–2.5) |
0.331¶ |
Seasonal influenza (H1N1) (A/Luxembourg/572/2008)# | |||
>10 | 183 (87.1; 83–91.9) | 132 (59.7; 53.2–66) | <0.001§ |
>20 | 125 (59.5; 52.8–65.9) | 76 (34.4; 28.4–40.9) | <0.001§ |
>40 | 61 (29; 23.3–35.5) | 39 (17.6; 13.2–23.2) | 0.007§ |
>80 | 21 (10; 6.6–14.9) | 17 (7.7; 4.8–12) | 0.500§ |
>160 | 14 (6.7; 3.9–11) | 7 (3.2; 1.4–6.5) | 0.144§ |
>320 | 11 (5.2; 2.9–9.2) | 4 (1.8; 0.5–4.7) | 0.093§ |
*Values are no. persons with antibodies. CI, confidence interval; SIV, swine influenza virus. Boldface indicates significance (p<0.05).
†p<0.05 when compared with swine workers against avian-like SIV (H1N1) of the same titer cutoff.
‡p<0.003 when compared with swine workers against avian-like SIV (H1N1) of the same titer cutoff.
§χ2 test on 2-way table.
¶z-test.
#Data for 210 swine workers, 221 controls.
Page created: July 25, 2011
Page updated: July 25, 2011
Page reviewed: July 25, 2011
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