Demographic data
| No LRTI | Viral-negative LRTI | RSV LRTI | Other viral LRTI | p Value | |
| n | 86 | 15 | 27 | 31 | |
| Gestational age (weeks) | 34 (32–35) | 34 (31–35) | 33 (30–34) | 33 (29–35) | 0.11 |
| Birth weight (g) | 2070 (1605–2413) | 2026 (1586–2312) | 1830 (1335–2065) | 1565 (1261–2152) | 0.02 |
| Males | 46 (56%) | 9 (60%) | 14 (52%) | 17 (55%) | 0.97 |
| Antenatal smoking | 14 (16%) | 2 (13%) | 4 (15%) | 7 (23%) | 0.82 |
| Antenatal steroids | 52 (60%) | 11 (73%) | 22 (81%) | 25 (81%) | 0.07 |
| Surfactant | 12 (14%) | 2 (13%) | 6 (22%) | 12 (39%) | 0.03 |
| Duration of ventilation (days) | 0 (0–2) | 1 (0–1.5) | 1 (0–5) | 1 (0–4.5) | 0.25 |
| Bronchopulmonary dysplasia | 6 (7%) | 1 (7%) | 3 (11%) | 6 (19%) | 0.25 |
| Parental atopy | 43 (50%) | 6 (40%) | 9 (33%) | 12 (42%) | 0.42 |
| Day care | 2 (2%) | 0 (0%) | 1 (4%) | 2 (6%) | 0.61 |
| Number of siblings | 1 (0–2) | 2 (1–2) | 1 (0–2) | 1 (0–2) | 0.17 |
| Palivizumab | 1 (1%) | 1 (7%) | 1 (4%) | 4 (13%) | 0.05 |
Data are expressed as median (IQR) or n (%).
LTRI, lower respiratory tract infection; RSV, respiratory syncitial virus.