| 2012–2013, n (%) | 2013–2014, n (%) | 2014–2015, n (%) | Total, n (%) | |
|---|---|---|---|---|
| N | 2184 | 1772 | 2067 | 6023 |
| Symptoms (MD = 0) | ||||
| Fever | 1162 (53.2) | 820 (46.3) | 1057 (51.1) | 3039 (50.5) |
| Chills | 950 (43.5) | 696 (39.3) | 898 (43.4) | 2544 (42.2) |
| Coryza | 1578 (72.3) | 1309 (73.9) | 1538 (74.4) | 4425 (73.5) |
| Sneezing | 1206 (55.2) | 970 (54.7) | 1120 (54.2) | 3296 (54.7) |
| Sore throat | 1516 (69.4) | 1287 (72.6) | 1377 (66.6) | 4180 (69.4) |
| Cough | 1606 (73.5) | 1256 (70.9) | 1549 (74.9) | 4411 (73.2) |
| Dyspnoea | 440 (20.1) | 355 (20.0) | 476 (23.0) | 1271 (21.1) |
| Headaches | 1427 (65.3) | 1151 (65.0) | 1362 (65.9) | 3940 (65.4) |
| Pain | 898 (41.1) | 637 (35.9) | 771 (37.3) | 2306 (38.2) |
| Sputum | 436 (20.0) | 346 (19.5) | 366 (17.7) | 1148 (19.1) |
| Asthenia | 1086 (49.7) | 809 (45.7) | 1008 (48.8) | 2903 (48.2) |
| Sudden onset of symptoms (MD = 84) | ||||
| Yes | 2018 (93.7) | 1649 (94.3) | 1915 (94.1) | 5582 (94.0) |
| No | 136 (6.3) | 100 (5.7) | 121 (5.9) | 357 (6.0) |
| Mean health score (± SD) (MD = 94) | – | – | 42.8 (± 21.4) | – |
| Activities modification (MD = 50) | ||||
| No | 1056 (48.7) | 937 (53.4) | 975 (47.6) | 2968 (49.7) |
| Yes, without taking time off work/school | 662 (30.5) | 513 (29.2) | 631 (30.8) | 1806 (30.2) |
| Yes, with taking time off work/school | 450 (20.8) | 306 (17.4) | 443 (21.6) | 1199 (20.1) |
ILI = influenza-like illness. MD = missing data. SD = standard deviation.