Table 4.
Geometric Mean Hemagglutination Inhibition and Microneutralization Titers to the 2009 H1N1 Influenza Vaccine According to Prior Receipt of 2008–2009 and/or 2009–2010 Seasonal Influenza Vaccines
| Assay | Dose group | Received 2008–2009 and/or 2009–2010 seasonal influenza vaccine | No. of subjects | Day 0, GMT (95% CI) | No. of subjects | Day 21 after dose 1, GMT (95% CI) | No. of subjects | Day 21 after dose 2, GMT (95% CI) |
| HAI | 25 μg | No | 10 | 5.2 (4.8–5.6) | 10 | 355.1 (142.5–884.9) | 8 | 349.0 (123.8–983.4) |
| Yes | 44 | 7.2 (5.3–9.8) | 44 | 380.5 (240.8–601.4) | 29 | 347.9 (196.1–617.2) | ||
| 49 μg | No | 17 | 5.8 (4.3–7.8) | 17 | 417.1 (225.3–772.1) | 14 | 430.7 (264.0–702.5) | |
| Yes | 40 | 6.7 (5.0–8.9) | 40 | 489.3 (312.8–765.2) | 36 | 320.0 (186.2–549.9) | ||
| MN | 25 μg | No | 10 | 5.0 (…)1 | 10 | 320.0 (129.4–791.2) | 8 | 293.4 (106.6–807.8) |
| Yes | 44 | 11.0 (8.0–15.0) | 44 | 467.0 (309.1–705.6) | 29 | 574.7 (376.5–877.3) | ||
| 49 μg | No | 17 | 6.8 (4.5–10.3) | 17 | 461.9 (257.1–829.7) | 14 | 551.7 (320.8–948.7) | |
| Yes | 40 | 11.3 (8.3–15.4) | 40 | 662.6 (462.2–949.8) | 36 | 543.4 (385.3–766.4) |
NOTE. CI, confidence interval.
1
All samples had the same value (below the limit of detection of a titer of 1:10), and therefore confidence intervals could not be calculated.