Table 1.
Characteristics of Influenza-Positive Cases and Influenza-Negative Controls by Influenza Season (N = 2,474)
| Characteristics, n (%) | 2003–2004 Influenza Season | 2004–2005 Influenza Season | ||||
|---|---|---|---|---|---|---|
| Cases (N = 228) | Controls (N = 744) | P | Cases (n = 197) | Controls (n = 1,305) | P | |
| Age group | .002 | .491 | ||||
| 6 to 23 months | 106 (46.5) | 432 (58.1) | 109 (55.3) | 756 (57.9) | ||
| 24 to 59 months | 122 (53.5) | 312 (41.9) | 88 (44.7) | 549 (42.1) | ||
| Vaccination status | .001 | .028 | ||||
| Fully vaccinated | 8 (3.5) | 54 (7.3) | 24 (12.2) | 263 (20.2) | ||
| Partially vaccinated | 22 (9.7) | 134 (18.0) | 43 (21.8) | 272 (20.8) | ||
| Unvaccinated | 198 (86.8) | 556 (74.7) | 130 (66.0) | 770 (59.0) | ||
| Male gender | 120 (52.6) | 414 (55.7) | .424 | 121 (61.4) | 690 (52.9) | .025 |
| Insurance type | .920 | .405 | ||||
| Private | 69 (30.3) | 229 (30.8) | 61 (31.0) | 466 (35.7) | ||
| Public | 149 (65.4) | 486 (65.3) | 130 (66.0) | 790 (60.5) | ||
| None | 10 (4.4) | 28 (3.8) | 5 (2.5) | 46 (3.5) | ||
| Unknown | 0 (0.0) | 1 (0.1) | 1 (0.5) | 3 (0.2) | ||
| ARI visit setting | .142 | .243 | ||||
| Inpatient | 42 (18.4) | 154 (20.7) | 35 (17.8) | 294 (22.5) | ||
| ED | 110 (48.3) | 304 (40.9) | 54 (27.4) | 367 (28.1) | ||
| Outpatient | 76 (33.3) | 286 (38.4) | 108 (54.8) | 644 (49.4) | ||
| Geographic area | <.001 | <.001 | ||||
| Cincinnati | 66 (29.0) | 351 (47.2) | 38 (19.3) | 437 (33.5) | ||
| Nashville | 92 (40.4) | 112 (15.1) | 76 (38.6) | 446 (34.2) | ||
| Rochester | 70 (30.7) | 281 (37.8) | 83 (42.1) | 422 (32.3) | ||
| High-risk conditiona | 59 (25.9) | 242 (32.5) | .057 | 50 (25.4) | 359 (27.5) | .532 |
a
High-risk conditions included asthma, cancer, diabetes, heart disease, immune deficiency, kidney disease, sickle cell disease, cystic fibrosis, and chronic lung disease.