Distribution of children hospitalised for the study conditions
| Conditions | Patients, N (%) | Median age (IQR) | Female, N (%) | Exposed to drug(s), N (%) | Exposed to vaccine,* N (%) | Underlying chronic diseases, N (%) |
| Neurological disorders | 241 (49) | 4 (9) | 112 (47) | 166 (69) | 53 (22) | 35 (15) |
| Muco-cutaneous diseases and vasculitis | 144 (29) | 5 (5) | 53 (37) | 110 (76) | 18 (13) | 14 (10) |
| Thrombocytopaenia | 60 (12) | 4 (7) | 21 (35) | 40 (67) | 17 (28) | 10 (17) |
| Gastroduodenal lesions | 47 (10) | 5 (6) | 20 (43) | 33 (70) | 8 (17) | 6 (13) |
| Total | 492 (100) | 4 (7) | 206 (42) | 349 (71) | 96 (20) | 65 (13) |
| Influenza-like illness | 244 | 3 (3) | 108 (44) | 170 (70) | 77 (32) | 58 (24) |
↵* All vaccines administered to the study subjects, and not only those with influenza, are included; 25 children exposed to the pandemic vaccine were distributed as follows: six cases (2.5%) were hospitalised for neurological disorders, 4 (2.8%) for muco-cutaneous diseases and vasculitis, 2 (4.3%) for gastroduodenal lesions and 13 (5.3%) for influenza-like illness. IQR, interquartile range.