| No LRTI | RV LRTI | RSV LRTI | RV/RSV LRTI | Overall p-value | |
| Subjects | 74 | 20 | 17 | 12 | |
| Gestational age weeks | 34.1 (25.7–35.9) | 32.9 (27.4–35.7) | 32.6 (28.9–35.6) | 32.1 (23.0–35.9) | 0.044 |
| Birthweight g | 2070 (895–3610) | 1558 (670–2512) | 1756 (1080–2650) | 1595 (610–2546) | 0.002 |
| Males | 39 (53) | 9 (45) | 9 (53) | 5 (42) | 0.85 |
| Ethnicity | 0.043 | ||||
| Caucasian | 28 (38) | 2 (10) | 3 (18) | 2 (17) | |
| Black Caribbean | 19 (26) | 2 (10) | 5 (29) | 2 (17) | |
| Black African | 12 (16) | 4 (20) | 5 (29) | 2 (17) | |
| Asian | 3 (4) | 2 (10) | 1 (6) | 0 (0) | |
| Hispanic | 1 (1) | 0 (0) | 0 (0) | 1 (8) | |
| Mixed race | 11 (15) | 10 (50) | 3 (18) | 5 (41) | |
| Antenatal smoking# | 11 (15) | 4 (20) | 2 (12) | 2 (17) | 0.91 |
| Antenatal steroids | 40 (54) | 16 (80) | 16 (94) | 8 (67) | 0.014 |
| Surfactant | 11 (15) | 7 (35) | 1 (6) | 6 (50) | 0.005 |
| Duration of ventilation days | 0 (0–82) | 1 (0–103) | 1 (0–17) | 1.5 (0–81) | 0.39 |
| Bronchopulmonary dysplasia | 4 (5) | 5 (25) | 0 (0) | 3 (25) | 0.008 |
| Family history of atopy¶ | 52 (70) | 13 (65) | 8 (47) | 7 (58) | 0.32 |
| Breastfeeding | 62 (84) | 15 (75) | 11 (65) | 8 (67) | 0.20 |
| Eczema | 20 (28) | 3 (16) | 2 (12) | 2 (17) | 0.45 |
| Daycare attendance | 2 (3) | 0 (0) | 1 (6) | 1 (8) | 0.52 |
| Number of siblings | 1 (0–5) | 1 (0–5) | 1 (0–4) | 1 (0–4) | 0.91 |
| Palivizumab | 0 (0) | 3 (15) | 0 (0) | 1 (8) | 0.005 |
Data are presented as n, median (range) or n (%), unless otherwise stated. RV: rhinovirus; RSV: respiratory syncytial virus. #: all mothers who smoked antenatally also smoked postnatally; ¶: a family history of atopy was defined as a first degree relative (parent or sibling) with asthma, eczema, hay fever or an allergy.