Size of cohorts and defining ICD-10 codes
| Groups | N | ICD-10 codes | |
| Bronchiolitis (60% male) | RSV | 4399 | J12.1, J21.0 |
| Non-RSV | 243 | J12.0, J12.2, J12.3, J12.8, J21.1, J21.8 | |
| Unspecified | 13 304 | J12.9, J21.9 | |
| UTI (control) (52% male) | 3326 | N39.0 | |
| Outcomes | Wheezing | 4472 | J45.*, J46*, R06.2 |
| Head injury | 325 | S09* | |
| Excluded | Neonatal admissions | 4654 | NA |
| Both diagnoses | 191 | NA | |
ICD-10, International Classification of Diseases, 10th revision; RSV, respiratory syncytial virus; NA, not applicable; UTI, urinary tract infection.