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Volume 18, Number 5—May 2012

No Association between 2008–09 Influenza Vaccine and Influenza A(H1N1)pdm09 Virus Infection, Manitoba, Canada, 2009

Salaheddin M. MahmudComments to Author , Paul Van Caeseele, Gregory Hammond, Carol Kurbis, Tim Hilderman, and Lawrence Elliott
Author affiliations: University of Manitoba, Winnipeg, Manitoba, Canada (S.M. Mahmud, P. Van Caeseele, G. Hammond, T. Hilderman, L. Elliott); Winnipeg Regional Health Authority, Winnipeg (S.M. Mahmud, C. Kurbis); Cadham Provincial Laboratory, Winnipeg (P.V. Caeseele); Manitoba Health, Winnipeg (T. Hilderman, L. Elliott)

Main Article

Table 3

Association between receipt of seasonal influenza vaccine and subsequent infection with influenza A(H1N1)pdm09 virus, by vaccine type, Manitoba, Canada, 2009*

Variable No. community controls, n = 2,479 No. community case-patients, n = 626 Odds ratio (95% CI)
Model A† Model B‡ Model C§
Received TIV
2007–08 544 123 0.9 (0.7–1.1) 1.3 (1.0–1.7) 1.4 (1.0–1.9)
2008–09 564 109 0.7 (0.6–0.9) 1.1 (0.8–1.4) 1.0 (0.7–1.4)
Vaccinated with
None 1,728 466 Referent Referent Referent
2007–08 only 187 51 1.0 (0.7–1.4) 1.3 (0.9–1.8) 1.3 (0.9–1.9)
2008–09 only 207 37 0.7 (0.5–1.0) 0.9 (0.6–1.3) 0.9 (0.6–1.4)
Both 357 72 0.7 (0.6–1.0) 1.3 (0.9–1.8) 1.4 (1.0–2.0)
No. TIVs in past 5 y
None 1,450 383 Referent Referent Referent
At least 1 1,029 243 0.9 (0.7–1.1) 1.2 (1.0–1.5) 1.2 (1.0–1.5)
1–3 711 187 1.0 (0.8–1.2) 1.2 (0.9–1.5) 1.2 (0.9–1.5)
4–5 318 56 0.7 (0.5–0.9) 1.3 (0.9–1.9) 1.4 (1.0–2.2)
5 156 19 0.5 (0.3–0.8) 0.8 (0.4–1.4) 0.8 (0.4–1.4)
Ever received PPV23 343 41 0.4 (0.3–0.6) 0.9 (0.6–1.4) 0.9 (0.6–1.5)
Vaccinated with
None 1,796 499 Referent Referent Referent
2008–09 TIV only 340 86 0.9 (0.7–1.2) 1.1 (0.8–1.4) 1.0 (0.7–1.4)
PPV23 only 119 18 0.5 (0.3–0.9) 0.9 (0.5–1.5) 0.9 (0.5–1.6)
Both 224 23 0.4 (0.2–0.6) 1.0 (0.6–1.7) 1.0 (0.5–1.8)

*TIV, inactivated trivalent influenza vaccine; PPV23, pneumococcal polysaccharide vaccine.
†Unadjusted model.
‡Model adjusted for age, sex, region of residence, Socioeconomic Factor Index (24), and week of specimen collection.
§Model adjusted for all model B variables plus no. of hospital admissions and family physician visits in previous 12 mo, pregnancy, having a chronic or immunocompromising medical condition, and antiviral drug use. Model also included mutual adjustment for 2007–09 TIV and PPV23.

Main Article

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