Table 3. Comparison of clinical features and outcomes between the influenza A and B groups in each age group.
| Factor | 0–2 years | 3–6 years | 7–12 years | 13–19 years | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Influenza A group (n=430) | Influenza B group (n=186) | P | Influenza A group (n=549) | Influenza B group (n=385) | P | Influenza A group (n=413) | Influenza B group (n=288) | P | Influenza A group (n=196) | Influenza B group (n=105) | P | ||||
| Male sex | 235 (54.7) | 111 (59.7) | 0.252 | 309 (56.3) | 214 (55.6) | 0.841 | 223 (54.0) | 147 (51.0) | 0.443 | 89 (45.4) | 46 (43.8) | 0.809 | |||
| Underlying disease | 5 (1.2) | 1 (0.5) | 0.674 | 13 (2.4) | 6 (1.6) | 0.484 | 10 (2.4) | 8 (2.8) | 0.811 | 11 (5.6) | 4 (3.8) | 0.588 | |||
| Clinical diagnoses | 0.034 | 0.620 | 0.654 | 0.009 | |||||||||||
| Upper respiratory tract infection | 345 (80.2) | 136 (73.1) | 478 (87.1) | 334 (86.8) | 381 (92.3) | 260 (90.3) | 192 (98.0) | 95 (90.5) | |||||||
| Lower respiratory tract infection | 77 (17.9) | 48 (25.8) | 61 (11.1) | 47 (12.2) | 26 (6.3) | 25 (8.7) | 3 (1.5) | 8 (7.6) | |||||||
| Fever without a focus | 8 (1.9) | 1 (0.5) | 5 (0.9) | 3 (0.8) | 2 (0.5) | 1 (0.3) | 1 (0.5) | 0 (0.0) | |||||||
| Acute gastroenteritis | 0 (0.0) | 1 (0.5) | 5 (0.9) | 1 (0.3) | 4 (1.0) | 2 (0.7) | 0 (0.0) | 2 (1.9) | |||||||
| Clinical symptoms | |||||||||||||||
| Fever | 429 (99.8) | 185 (99.5) | 0.513 | 549 (100.0) | 384 (99.7) | 0.412 | 412 (99.8) | 287 (99.7) | 1.000 | 192 (98.0) | 103 (98.1) | 1.000 | |||
| Respiratory symptoms, any | 392 (91.2) | 176 (94.6) | 0.189 | 500 (91.1) | 363 (94.3) | 0.079 | 391 (94.7) | 271 (94.1) | 0.741 | 189 (96.4) | 101 (96.2) | 1.000 | |||
| Cough | 351 (81.6) | 155 (83.3) | 0.648 | 457 (83.2) | 330 (85.7) | 0.317 | 349 (84.5) | 243 (84.4) | 1.000 | 165 (84.2) | 88 (83.8) | 1.000 | |||
| Rhinorrhea | 329 (76.5) | 156 (83.9) | 0.042 | 365 (66.5) | 258 (67.0) | 0.888 | 242 (58.6) | 171 (59.4) | 0.876 | 107 (54.6) | 68 (64.8) | 0.111 | |||
| Sputum | 184 (42.8) | 101 (54.3) | 0.011 | 253 (46.1) | 156 (40.5) | 0.094 | 162 (39.2) | 112 (38.9) | 0.937 | 87 (44.4) | 50 (47.6) | 0.628 | |||
| Sore throat | 14(3.3) | 5 (2.7) | 0.805 | 55 (10.0) | 65 (16.9) | 0.003 | 114 (27.6) | 88 (30.6) | 0.398 | 87 (44.4) | 54 (51.4) | 0.276 | |||
| Dyspnea | 11 (2.6) | 1 (0.5) | 0.119 | 3 (0.5) | 3 (0.8) | 0.695 | 3 (0.7) | 1 (0.3) | 0.648 | 4 (2.0) | 0 (0.0) | 0.302 | |||
| Gastrointestinal symptoms, any | 77 (17.9) | 32 (17.2) | 0.909 | 120 (21.9) | 79 (20.5) | 0.685 | 74 (17.9) | 49 (17.0) | 0.840 | 30 (15.3) | 19 (18.1) | 0.623 | |||
| Vomiting | 51 (11.9) | 17 (9.1) | 0.401 | 72 (13.1) | 41 (10.6) | 0.264 | 50 (12.1) | 30 (10.4) | 0.547 | 18 (9.2) | 9 (8.6) | 1.000 | |||
| Abdominal pain | 11 (2.6) | 6 (3.2) | 0.603 | 64 (11.7) | 52 (13.5) | 0.421 | 34 (8.2) | 22 (7.6) | 0.888 | 12 (6.1) | 10 (9.5) | 0.353 | |||
| Diarrhea | 27 (6.3) | 13 (7.0) | 0.725 | 19 (3.5) | 11 (2.9) | 0.708 | 7 (1.7) | 9 (3.1) | 0.304 | 6 (3.1) | 5 (4.8) | 0.524 | |||
| Headache | 5 (1.2) | 1 (0.5) | 0.674 | 29 (5.3) | 23 (6.0) | 0.666 | 82 (19.9) | 54 (18.8) | 0.771 | 55 (28.1) | 33 (31.4) | 0.595 | |||
| Myalgia | 0 (0.0) | 1 (0.5) | 0.302 | 24 (4.4) | 14 (3.6) | 0.618 | 28 (6.8) | 26 (9.0) | 0.314 | 55 (28.1) | 29 (27.6) | 1.000 | |||
| Seizure activity | 29 (6.7) | 12 (6.5) | 1.000 | 27 (4.9) | 9 (2.3) | 0.056 | 7 (1.7) | 2 (0.7) | 0.321 | 0 (0.0) | 1 (1.0) | 0.349 | |||
| Antiviral therapy | 344 (80.0) | 153 (82.3) | 0.579 | 447 (81.4) | 317 (82.3) | 0.731 | 308 (74.6) | 226 (78.5) | 0.243 | 152 (77.6) | 81 (77.1) | 1.000 | |||
| Outcomes | |||||||||||||||
| Hospitalization | 125 (29.1) | 79 (42.5) | 0.001 | 117 (21.3) | 74 (19.2) | 0.459 | 83 (20.1) | 53 (18.4) | 0.628 | 24 (12.2) | 16 (15.2) | 0.480 | |||
| Oxygen therapy | 1 (0.2) | 0 (0.0) | 1.000 | 1 (0.2) | 0 (0.0) | 1.000 | 1 (0.2) | 0 (0.0) | 1.000 | 2 (1.0) | 0 (0.0) | 0.544 | |||
| Mechanical ventilation | 0 (0.0) | 0 (0.0) | NA | 0 (0.0) | 0 (0.0) | NA | 0 (0.0) | 0 (0.0) | NA | 1 (0.5) | 0 (0.0) | 1.000 | |||
| Acute otitis media | 18 (4.2) | 8 (4.3) | 1.000 | 7 (1.3) | 6 (1.6) | 0.780 | 0 (0.0) | 1 (0.3) | 0.411 | 0 (0.0) | 0 (0.0) | NA | |||
| Sinusitis | 2 (0.5) | 1 (0.5) | 1.000 | 2 (0.4) | 2 (0.5) | 1.000 | 2 (0.5) | 0 (0.0) | 0.515 | 2 (1.0) | 3 (2.9) | 0.347 | |||
NA, not applicable.