Table 2.
Characteristics of Laboratory-Confirmed Influenza Cases, Stratified by Age Group
| Feature, N (%) | <5 Years | 5–17 Years | 18–49 Years | 50–64 Years | 65–79 Years | 80+ Years | P for Temporal Trend |
|---|---|---|---|---|---|---|---|
| N | 1149 (32.7) | 359 (10.2) | 769 (21.9) | 456 (13.0) | 504 (14.4) | 275 (7.8) | … |
| Male sex | 516 (44.9) | 153 (42.6) | 477 (62.0) | 233 (51.1) | 236 (46.8) | 156 (56.7) | .452 |
| Smoking Habit | |||||||
| Current smoker (parent smoking status for children) | 348 (30.3) | 101 (28.1) | 186 (24.2) | 149 (32.7) | 105 (20.8) | 20 (7.3) | .132 |
| Never smoker | 635 (55.3) | 212 (59.1) | 499 (64.9) | 180 (39.5) | 201 (39.9) | 160 (58.2) | 1.000 |
| Past smoker | 121 (10.5) | 40 (11.1) | 84 (10.9) | 127 (27.9) | 198 (39.3) | 95 (34.5) | 1.000 |
| Not available | 45 (3.9) | 6 (1.7) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | … |
| Influenza Vaccination in the Current Season | 39 (3.4) | 18 (5.0) | 33 (4.3) | 37 (8.1) | 99 (19.6) | 97 (35.3) | .024 |
| Not available | 31 (2.7) | 5 (1.4) | 23 (3.0) | 31 (6.8) | 37 (7.3) | 26 (9.5) | … |
| Presenting Symptoms | |||||||
| Fever | 0 (0.0) | 355 (98.9) | 743 (96.6) | 431 (94.5) | 455 (90.3) | 222 (80.7) | .027 |
| Not available | 1149 (100) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | … |
| Cough | 0 (0.0) | 341 (95.0) | 695 (90.4) | 425 (93.2) | 441 (87.5) | 235 (85.5) | 0.086 |
| Not available | 1149 (100) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | … |
| Shortness of breath | 0 (0.0) | 75 (20.9) | 267 (34.7) | 265 (58.1) | 311 (61.7) | 207 (75.3) | 0.027 |
| Not available | 1149 (100) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | … |
| Malaise | 0 (0.0) | 282 (78.6) | 574 (74.6) | 327 (71.7) | 323 (64.1) | 186 (67.6) | 0.086 |
| Not available | 1149 (100) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | … |
| Headache | 0 (0.0) | 158 (44.0) | 470 (61.1) | 222 (48.7) | 213 (42.3) | 75 (27.3) | .220 |
| Not available | 1149 (100) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | … |
| Myalgias | 0 (0.0) | 120 (33.4) | 384 (49.9) | 236 (51.8) | 230 (45.6) | 111 (40.4) | 1.000 |
| Not available | 1149 (100) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | … |
| Sore throat | 0 (0.0) | 175 (48.7) | 372 (48.4) | 184 (40.4) | 167 (33.1) | 65 (23.6) | .027 |
| Not available | 1149 (100) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | … |
| Chronic Comorbidities | |||||||
| Any chronic comorbidities | 124 (10.8) | 58 (16.2) | 283 (36.8) | 352 (77.2) | 460 (91.3) | 261 (94.9) | .008 |
| Not available | 1 (0.1) | 0 (0) | 0 (0) | 0 (0) | 1 (0.2) | 0 (0) | … |
| Cardiovascular disease/high blood pressure | 17 (1.5) | 6 (1.7) | 55 (7.2) | 185 (40.6) | 318 (63.1) | 190 (69.1) | .024 |
| Not Available | 183 (15.9) | 15 (4.2) | 4 (0.5) | 6 (1.3) | 9 (1.8) | 4 (1.5) | … |
| Chronic obstructive pulmonary disease | 13 (1.1) | 5 (1.4) | 21 (2.7) | 81 (17.8) | 149 (29.6) | 78 (28.4) | 0.024 |
| Not available | 35 (3.0) | 4 (1.1) | 4 (0.5) | 6 (1.3) | 9 (1.8) | 4 (1.5) | … |
| Asthma | 9 (0.8) | 17 (4.7) | 42 (5.5) | 28 (6.1) | 35 (6.9) | 26 (9.5) | .008 |
| Not available | 183 (15.9) | 15 (4.2) | 4 (0.5) | 6 (1.3) | 9 (1.8) | 4 (1.5) | … |
| Diabetes mellitus | 1 (0.1) | 0 (0.0) | 44 (5.7) | 103 (22.6) | 153 (30.4) | 74 (26.9) | .060 |
| Not available | 35 (3.0) | 4 (1.1) | 4 (0.5) | 6 (1.3) | 9 (1.8) | 4 (1.5) | … |
| Immunodeficiency (except HIV)/organ transplant | 7 (0.6) | 2 (0.6) | 27 (3.5) | 17 (3.7) | 19 (3.8) | 6 (2.2) | .259 |
| Not available | 35 (3.0) | 4 (1.1) | 4 (0.5) | 6 (1.3) | 9 (1.8) | 4 (1.5) | … |
| Renal impairment | 1 (0.1) | 0 (0.0) | 19 (2.5) | 37 (8.1) | 53 (10.5) | 44 (16.0) | .024 |
| Not available | 35 (3.0) | 4 (1.1) | 4 (0.5) | 6 (1.3) | 9 (1.8) | 4 (1.5) | … |
| Rheumatologic disease/autoimmune disease | 0 (0.0) | 1 (0.3) | 18 (2.3) | 18 (3.9) | 27 (5.4) | 24 (8.7) | .008 |
| Not available | 35 (3.0) | 4 (1.1) | 4 (0.5) | 6 (1.3) | 9 (1.8) | 4 (1.5) | … |
| Neurological or neuromuscular disease | 9 (0.8) | 8 (2.2) | 14 (1.8) | 20 (4.4) | 37 (7.3) | 39 (14.2) | .024 |
| Not available | 35 (3.0) | 4 (1.1) | 4 (0.5) | 6 (1.3) | 9 (1.8) | 4 (1.5) | … |
| Cirrhosis/liver disease | 2 (0.2) | 2 (0.6) | 14 (1.8) | 20 (4.4) | 19 (3.8) | 6 (2.2) | .132 |
| Not available | 35 (3.0) | 4 (1.1) | 4 (0.5) | 6 (1.3) | 9 (1.8) | 4 (1.5) | … |
| Neoplasm | 1 (0.1) | 8 (2.2) | 24 (3.1) | 42 (9.2) | 66 (13.1) | 29 (10.5) | .024 |
| Not available | 35 (3.0) | 4 (1.1) | 4 (0.5) | 6 (1.3) | 9 (1.8) | 4 (1.5) | … |
| Obesity | 0 (0.0) | 0 (0.0) | 52 (6.8) | 48 (10.5) | 66 (13.1) | 49 (17.8) | .012 |
| Not available | 35 (3.0) | 4 (1.1) | 33 (4.3) | 29 (6.4) | 30 (6.0) | 25 (9.1) | … |
| Active tuberculosis | 0 (0.0) | 0 (0.0) | 2 (0.3) | 1 (0.2) | 0 (0.0) | 0 (0.0) | 1.000 |
| Not available | 36 (3.1) | 6 (1.7) | 18 (2.3) | 44 (9.6) | 104 (20.6) | 101 (36.7) | … |
| HIV infection | 19 (1.7) | 0 (0.0) | 13 (1.7) | 3 (0.7) | 2 (0.4) | 0 (0.0) | .338 |
| Not available | 36 (3.1) | 6 (1.7) | 18 (2.3) | 44 (9.6) | 104 (20.6) | 101 (36.7) | … |
| Antivirals | 339 (29.5) | 92 (25.6) | 210 (27.3) | 127 (27.9) | 157 (31.2) | 94 (34.2) | .132 |
Abbreviations: HIV, human immunodeficiency virus.