Table 2.
Estimates of TIV effectiveness against influenza A and B viruses, 2009–13
| Vaccine effectivenessa (95% confidence interval)
|
|||
|---|---|---|---|
| Test-positive vs all test-negative cases | Test-positive versus pan-negative cases b | Test-positive versus non-influenza virus positive casesc | |
| Influenza A or B | 61.7% (43.0%, 74.2%) | 64.4% (46.4%, 76.3%) | 62.5% (38.5%, 77.1%) |
| Influenza A | 56.9% (29.2%, 73.8%) | 59.5% (32.4%, 75.7%) | 63.3% (33.1%, 79.8%) |
| Influenza A(H1N1)pdm09 | 71.5% (39.4%, 86.6%) | 73.5% (42.7%, 87.8%) | 74.9% (40.9%, 89.3%) |
| Influenza A(H3N2) | 36.6% (−25.5%, 67.9%) | 37.9% (−24.8%, 69.1%) | 45.4% (−24.9%, 76.2%) |
| Influenza B | 68.8% (41.6%, 83.3%) | 72.1% (47.0%, 85.3%) | 63.8% (19.2%, 83.8%) |
Effectiveness of TIV in the past 6 months based on conditional logistic regression, adjusted for age, age squared, sex, and receipt of monovalent H1N1pdm09 vaccine in 2009–10, and matched by calendar week.
Pan-negative cases included the cases who tested negative for influenza virus and were also negative for other respiratory viruses including respiratory syncytial virus, parainfluenza virus type 1, 2, 3 and adenovirus using the IMAGENTM typing kit.
Non-influenza virus positive cases included the cases who tested negative for influenza virus but were positive for other respiratory viruses including respiratory syncytial virus, parainfluenza virus type 1, 2, 3 or adenovirus using the IMAGENTM typing kit.