Table 3.
ORs for increased serologic response against swine influenza virus by hemagglutination inhibition assay, determined by proportional odds modeling.
| Virus |
||||||
|---|---|---|---|---|---|---|
| Swine H1N1 |
Swine H1N2 |
Swine H3N2 |
||||
| Population | Unadjusted OR (95% CI) | Adjusted OR (95% CI)a | Unadjusted OR (95% CI) | Adjusted OR (95% CI)b | Unadjusted OR (95% CI) | Adjusted OR (95% CI)c |
| Occupation | ||||||
| Farmer | 32.7 (7.6–139.8) | 35.3 (7.7–161.8) | 15.9 (6.8–37.1) | 13.8 (5.4–35.4) | 0.4 (0.3–0.7) | 0.4 (0.2–0.8) |
| Meat processing worker | 7.5 (1.7–33.6) | 6.5 (1.4–29.5) | 3 (1.2–7.3) | 2.7 (1.1–6.7) | 1.5 (0.9–2.6) | 1.5 (0.9–2.6) |
| Veterinarian | 23.1 (5.2–102.4) | 17.8 (3.8–82.7) | 13 (5.3–31.8) | 9.5 (3.6–24.6) | 0.6 (0.3–1.1) | 0.8 (0.4–1.5) |
| Age: years | 1 (1–1.1) | 1 (1–1) | 1 (1–1.1) | 1 (1–1) | 1 (1–1) | 1 (1–1) |
| Sex: male vs. female | 3.3 (1.9–5.5) | 2.9 (1.6–5.2) | 2.7 (1.8–4.2) | 2.3 (1.4–3.7) | 1.1 (0.7–1.5) | 1.2 (0.8–1.8) |
| Human influenza strain | ||||||
| H1N1 | 1.8 (1.1–3) | 2.8 (1.6–5) | 1.8 (1.1–2.8) | 2.7 (1.6–4.5) | … | … |
| H3N2 Panama | … | … | … | … | 5.6 (3.8–8.5) | … |
| H3N2 Nanchang | … | … | … | … | 44.6 (24.6–81) | 45.5 (25–83.1) |
| Vaccine historyd | ||||||
| Received 2003 flu vaccine | …e | …d | 2.1 (1–4.4) | …d | 3.6 (2–6.7) | …d |
| Received 1976 swine flu vaccine | …e | …d | 12.2 (3.6–41.7) | …d | 2.9 (0.9–9.4) | …d |
NOTE. To satisfy the proportional odds assumption, swine H1N1 and H1N2 titers of >1:80 were combined into 1 category, as were swine H3N2 titers of >1:320. Values shown in boldface are statistically significant.
a
P = .23, by score test.
b
P = .53, by score test.
c
P = .27, by score test.
d
Variable available for veterinarians and control subjects only.
e
Does not meet proportional odds assumption.