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Volume 18, Number 7—July 2012

Dispatch

Seroconversion to Seasonal Influenza Viruses after A(H1N1)pdm09 Virus Infection, Quebec, Canada

Mariana Baz, Jesse Papenburg, Marie-Eve Hamelin, Manale Ouakki, Danuta M. Skowronski, Gaston De Serres, and Guy BoivinComments to Author 
Author affiliations: Author affiliations: Centre Hospitalier Universitaire de Quebec, Quebec City, Quebec, Canada (M. Baz, J. Papenburg, M.-E. Hamelin, G. Boivin); Laval University, Quebec City (M. Baz, J. Papenburg, M.-E. Hamelin, G. Boivin); Institut National de Santé Publique du Quebec, Quebec (M. Ouakki, G. De Serres); British Columbia Centre for Disease Control, Vancouver, British Columbia, Canada (D.M. Skowronski)

Main Article

Table A1

Seroconversion rates and GMTs for pandemic and seasonal influenza viruses, Quebec City, Quebec, Canada, 2009*

A(H1N1)pdm09 virus Age, y
Received seasonal vaccine in 2008–09 A/Quebec/147023/2009; A(H1N1)pdm09
A/Brisbane/59/2007 (H1N1)
A/New Caledonia/99 (H1N1)
A/Panama/2007/99 (H3N2)
Mean† Median (range) Seroconversion rate† GMT (95% CI) Seroconversion rate† GMT (95% CI) Seroconversion rate† GMT (95% CI) Seroconversion rate GMT (95% CI)
Positive, n = 67‡ 25.7 20 (7–61) 19 (28) 57 (85) 69.2 (49.9–95.9) 8 (12) 104.7 (73.5–149.1) 7 (10) 96.5 (65.5–142.4) 6 (9) 285.6 (188.5–432.6)
Negative, n = 55 31.2 35.5 (8–55) 13 (24) 0 5.9 (5.2–6.8) 1 (2) 41.0 (28.4–59.2) 0 34.4 (22.2–53.3) 3 (5) 124.4 (77.5–199.6)

*Values are no. (%) except as indicated. Seroconversion defined as an acute-phase serum titer of <10 with a convalescent-phase titer of >40 or a significant increase (>4-fold) in antibody titers between acute- and convalescent-phase serum samples. GMT, geometric mean titer;
†p<0.05.
‡A(H1N1)pdm09-positive persons were defined by positive reverse transcription PCR and/or seroconversion by microneutralization assay.

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