Table 3.
Self-controlled risk interval and historical comparison analyses of pre-specified claims-identified outcomes following trivalent influenza virus vaccine in the 2009–2010 influenza season.
| Outcome | Age | Cases in the risk window (N) | Cases in the control window (N) | Incidence rate ratio | 95% confidence limits | Doses administered | Doses administered in historical cohort | |
|---|---|---|---|---|---|---|---|---|
| Self-controlled risk interval analysis | ||||||||
| Seizure | 6–59 months | 8 | 20 | 1.40 | 0.53 | 3.32 | 189.980 | NA |
| Bell’s Palsy | All Ages | 74 | 89 | 0.83 | 0.60 | 1.15 | 998,881 | NA |
| ≤24 years | 9 | 11 | 0.82 | 0.30 | 2.17 | 430,879 | NA | |
| ≥25 years | 65 | 78 | 0.83 | 0.60 | 1.16 | 568,002 | NA | |
| Other cranial nerve disorders | All Ages | 187 | 356 | 1.05 | 0.88 | 1.25 | 998,881 | NA |
| >24 years | 20 | 29 | 1.38 | 0.78 | 2.44 | 430,879 | NA | |
| ≥25 years | 167 | 327 | 1.02 | 0.85 | 1.23 | 568,002 | NA | |
| Central demyelinating disease | All Ages | 170 | 358 | 0.95 | 0.79 | 1.14 | 998,881 | NA |
| ≤24 years | 10 | 20 | 0.39 | 0.47 | 2.14 | 430,879 | NA | |
| ≥25 years | 160 | 338 | 0.95 | 0.78 | 1.14 | 568,002 | NA | |
| Guillain-Barré Syndrome | All Ages | 11 | 7 | 1.57 | 0.61 | 4.05 | 998,881 | NA |
| ≤24 years | 3 | 1 | 3.00 | 0.31 | 28.84 | 430,879 | NA | |
| ≥25 years | 8 | 6 | 1.33 | 0.46 | 3.84 | 568,002 | NA | |
| Disorders of the peripheral nervous system and neuropathy | All Ages | 1926 | 3614 | 1.07 | 1.01 | 1.13 | 998,881 | NA |
| ≤24 years | 53 | 79 | 1.34 | 0.95 | 1.90 | 430,879 | NA | |
| ≥25 years | 1873 | 3535 | 1.06 | 1.00 | 1.12 | 568,002 | NA | |
| Historical comparison analysis | ||||||||
| Anaphylaxis | All Ages | 8 | 1 | 28.55 | 3.57 | 228.44 | 998,881 | 3,508,144 |
| ≤24 | 5 | 0 | – | – | – | 430,879 | 1,559,970 | |
| ≥25 | 3 | 1 | 10.92 | 1.13 | 105.37 | 568,002 | 1,948,174 | |
| Ataxia | All Ages | 5 | 43 | 0.39 | 0.15 | 0.98 | 998,881 | 3,508,144 |
| ≤24 | 1 | 7 | 0.52 | 0.06 | 4.26 | 430,879 | 1,559,970 | |
| ≥25 | 4 | 36 | 0.37 | 0.13 | 1.03 | 568,002 | 1,948,174 | |
| Encephalitis/myelitis/encephalomyelitis | All Ages | 3 | 36 | 0.28 | 0.09 | 0.92 | 998,881 | 3,508,144 |
| ≤24 | 0 | 10 | – | – | – | 430,879 | 1,559,970 | |
| ≥25 | 3 | 26 | 0.39 | 0.12 | 1.28 | 568,002 | 1,948,174 | |
| Guillain-Barré Syndrome | All Ages | 11 | 33 | 1.16 | 0.58 | 2.29 | 998,881 | 3,508,144 |
| ≤24 | 3 | 4 | 2.72 | 0.61 | 12.17 | 430,879 | 1,559,970 | |
| ≥25 | 8 | 29 | 0.95 | 0.44 | 2.09 | 568,002 | 1,948,174 | |
| Angioneurotic edema, allergic reaction and urticaria | All Ages | 135 | 510 | 0.92 | 0.76 | 1.11 | 998,881 | 3,508,144 |
| ≤24 | 80 | 304 | 0.94 | 0.74 | 1.21 | 430,879 | 1,559,970 | |
| ≥25 | 55 | 206 | 0.89 | 0.66 | 1.20 | 568,002 | 1,948,174 | |
| Hemorrhagic stroke | All Ages | 70 | 193 | 1.24 | 0.94 | 1.63 | 998,881 | 3,508,144 |
| ≤24 | 10 | 15 | 2.37 | 0.95 | 5.65 | 430,879 | 1,559,970 | |
| ≥25 | 60 | 178 | 1.14 | 0.86 | 1.54 | 568,002 | 1,948,174 | |
| Ischemic stroke | All Ages | 157 | 589 | 0.91 | 0.76 | 1.08 | 998,881 | 3,508,144 |
| ≤24 | 4 | 14 | 1.07 | 0.35 | 3.25 | 430,879 | 1,559,970 | |
| ≥25 | 153 | 575 | 0.90 | 0.76 | 1.08 | 568,002 | 1,948,174 | |
| Narcolepsy and cataplexy | All Ages | 73 | 234 | 1.09 | 0.84 | 1.41 | 998,881 | 3,508,144 |
| ≤24 | 4 | 19 | 0.77 | 0.26 | 2.28 | 430,879 | 1,559,970 | |
| ≥25 | 69 | 215 | 1.11 | 0.85 | 1.46 | 568,002 | 1,948,174 | |