Table 3. Characteristics of influenza cases and test-negative controls included in the study by characteristics, I-MOVE multi-centre case control study, influenza season 2010-11.
| CasesN = 2019 | Test-negative controlsN = 2391 | P value | |
| Median age | 23 | 32 | <0.001* |
| Age group - n°/total n°. (%) | |||
| 0-4 | 269/2019 (13.3) | 372/2391 (15.6) | <0.001** |
| 5-14 | 503/2019 (24.9) | 286/2391 (12.0) | |
| 15-59 | 1117/2019 (55.3) | 1394/2391 (58.3) | |
| 60+ | 130/2019 (6.4) | 339/2391 (14.2) | |
| Female sex - n°/total n°. (%) | 1046/2012 (52.1) | 1241/2383 (52.1) | 1.000** |
| Symptoms - n°/total n°. (%) | |||
| Fever | 1964/2016 (97.5) | 2246/2381 (94.3) | <0.001** |
| Headache | 1446/1995 (72.5) | 1562/2361 (66.2) | <0.001** |
| Myalgia | 1487/1990 (74.7) | 1659/2361 (70.3) | 0.001** |
| Cough | 1891/2018 (93.7) | 2049/2382 (86.0) | <0.001** |
| Sore throat | 1361/1993 (68.3) | 1766/2376 (74.3) | <0.001** |
| Shortness of breath | 208/1959 (10.6) | 327/2349 (13.9) | 0.001** |
| Days between onset of symptoms and swabbing – n°/total n°. (%) | |||
| 0 | 138/2019 (6.8) | 170/2391 (7.1) | 0.002** |
| 1 | 944/2019 (46.8) | 1033/2391 (43.2) | |
| 2 | 587/2019 (29.1) | 650/2391 (27.2) | |
| 3 | 219/2019 (10.8) | 303/2391 (12.7) | |
| 4 | 74/2019 (3.7) | 116/2391 (4.9) | |
| 5 | 39/2019 (2.0) | 62/2391 (2.7) | |
| 6 | 9/2019 (0.4) | 32/2391 (1.3) | |
| 7 | 9/2019 (0.4) | 25/2391 (1.0) | |
| Mean swab delay | 1.7 | 1.8 | <0.001*** |
| Diabetes - n°/total n°. (%) | 30/1296 (2.3) | 90/1715 (5.2) | <0.001** |
| Heart disease | 62/1296 (4.8) | 201/1715 (11.7) | <0.001** |
| Any reported chronic disease | 219/1990 (11.0) | 428/2356 (18.2) | <0.001** |
| Any hospitalisation in the previous 12 months for chronic diseases - n°/total n°. (%) | 25/2012 (1.2) | 56/2371 (2.4) | 0.007** |
| Smoker - n°/total n°. (%) | |||
| Current | 165/1791 (9.2) | 319/2137 (14.9) | <0.001** |
| Former | 93/1791 (5.2) | 201/2137 (9.4) | |
| Never | 1534/1791 (85.6) | 1617/2137 (75.7) | |
| Pandemic vaccination 2009-10 - n°/total n°. (%) | 148/1994 (7.4) | 300/2348 (12.8) | <0.001** |
| Seasonal vaccination, 2009-10 - n°/total n°. (%) | 134/1990 (6.7) | 341/2349 (14.5) | <0.001** |
| Number of practitioner visits in previous 12 months | |||
| 0-1 | 695/1611 (43.1) | 631/2010 (31.4) | <0.001** |
| 2-4 | 482/1611 (29.9) | 657/2010 (32.7) | |
| 5+ | 434/1611 (27.0) | 722/2010 (35.9) | |
| Belongs to target group for vaccination n°/total n°. (%) | 381/2017 (18.9) | 631/2380 (26.5) | <0.001** |
*
Non parametric test of the median.
**
Two-sided Fisher's exact test *** T-test.