Volume 18, Number 7—July 2012
Dispatch
Seroconversion to Seasonal Influenza Viruses after A(H1N1)pdm09 Virus Infection, Quebec, Canada
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.