Table 1.
Characteristics of participants.
| Characteristics | All n = 43 |
IG n = 23 |
CG n = 20 |
|---|---|---|---|
| Gestational age, weeks, median (range) | 27 (23–41) |
26 (23–40) |
27.5 (24–41) |
| Gestational weight, kg, median, (range) | 0.935 (0.482–3.65) |
0.915 (0.482–3.63) |
1.075 (0.656–3.65) |
| Sex female/male (n) | 21/22 | 12/11 | 9/11 |
| Age at start of immunization, months, uncorrected median (range) | 8 (1.9-25) |
8 (2.5–20.1) |
8 (1.9–25) |
| BPD diagnosis (n) | 34 | 20 | 14 |
| CHD diagnosis or other circulatory disorder (n) | 7 | 2 | 5 |
| Other diagnosis * (n) | 2 | 1 | 1 |
| Medication for respiratory a/o circulatory disorder (n) | 16 | 8 | 8 |
| Oxygen treatment (n) | 2 | 2 | 0 |
| Second immunization period (n) | 10 | 8 | 2 |
| Verified RSV infection during immunization period (n) | 0 | 0 | 0 |
| Older siblings (yes, n) | 20 | 11 | 9 |
| Exposure to tobacco in home (n) | 3 | 1 | 2 |
| Smoking mother during pregnancy and/or breastfeeding (n) | 1 | 0 | 1 |
| Starting kindergarten during studied season (n) | 3 | 3 | 0 |
Abbreviations: IG—intervention group; CG—control group; n—number of participants; BPD—bronchopulmonary dysplasia; CHD—congenital heart disease. * One child born premature at gestational age 27 weeks who did not have BPD; one child born premature with multiple diseases, but not BPD or CHD.