Number of hospitalisations among 4262 Danish children by allocation to BCG vaccination at birth or control group (no intervention)
| Intention-to-treat analysis* | Allocated to BCG. Number of hospitalisations (n†) (mean‡) | Allocated to control. Number of hospitalisations (n†) (mean‡) | HR, crude | 95% CI | p Value of effect modification between the groups | HR, adjusted§ | 95% CI | p Value of effect modification between the groups |
|---|---|---|---|---|---|---|---|---|
| All n=4262 | 1047 (2129) (0.49) | 1003 (2133) (0.47) | 1.05 | 0.93 to 1.18 | 1.05 | 0.93 to 1.20 | ||
| Prematurity | 0.94 | 0.14 | ||||||
| Premature¶ n=144 | 62 (71) (0.87) | 59 (73) (0.81) | 1.07 | 0.63 to 1.81 | 1.56 | 0.91 to 2.66 | ||
| Mature n=4118 | 985 (2058) (0.48) | 944 (2060) (0.46) | 1.05 | 0.92 to 1.18 | 1.03 | 0.91 to 1.17 | ||
| Sex | 0.44 | 0.48 | ||||||
| Male n=2241 | 604 (1104) (0.55) | 570 (1137) (0.50) | 1.09 | 0.93 to 1.29 | 1.09 | 0.93 to 1.29 | ||
| Female n=2021 | 443 (1025) (0.43) | 433 (996) (0.44) | 0.99 | 0.83 to 1.20 | 1.00 | 0.82 to 1.21 | ||
| Study site | 0.20 | 0.12 | ||||||
| Rigshospitalet n=1567 | 383 (764) (0.50) | 391 (803) (0.49) | 1.04 | 0.85 to 1.28 | 1.02 | 0.82 to 1.27 | ||
| Hvidovre n=1470 | 451 (738) (0.61) | 384 (732) (0.53) | 1.16 | 0.96 to 1.41 | 1.21 | 0.99 to 1.47 | ||
| Kolding n=1225 | 213 (627) (0.34) | 228 (598) (0.38) | 0.88 | 0.69 to 1.12 | 0.87 | 0.68 to 1.11 | ||
| Per-protocol analysis** | BCG vaccinated. Number of hospitalisations (n†) (mean‡) | Control group. Number of hospitalisations (n†) (mean‡) | HR | 95%-CI | p Value of effect modification between the groups | HR, adjusted§ | 95%-CI | p Value of effect modification between the groups |
| All n=4215 | 1044 (2118) (0.49) | 979 (2097) (0.47) | 1.06 | 0.93 to 1.19 | 1.06 | 0.93 to 1.20 | ||
| Prematurity | 0.90 | 0.13 | ||||||
| Premature¶ n=143 | 62 (71) (0.87) | 57 (72) (0.79) | 1.09 | 0.64 to 1.87 | 1.60 | 0.92 to 2.77 | ||
| Mature n=4071 | 982 (2047) (0.48) | 922 (2025) (0.45) | 1.05 | 0.93 to 1.20 | 1.04 | 0.91 to 1.18 | ||
| Sex | 0.35 | 0.39 | ||||||
| Male n=2214 | 604 (1096) (0.55) | 554 (1118) (0.50) | 1.11 | 0.95 to 1.31 | 1.11 | 0.94 to 1.31 | ||
| Female n=2000 | 440 (1022) (0.43) | 425 (979) (0.43) | 0.99 | 0.82 to 1.19 | 1.00 | 0.82 to 1.21 | ||
| Study site | 0.28 | 0.17 | ||||||
| Rigshospitalet n=1543 | 383 (761) (0.50) | 379 (782) (0.49) | 1.05 | 0.85 to 1.30 | 1.03 | 0.83 to 1.28 | ||
| Hvidovre n=1456 | 448 (734) (0.61) | 379 (722) (0.53) | 1.16 | 0.96 to 1.41 | 1.20 | 0.98 to 1.46 | ||
| Kolding n=1215 | 213 (623) (0.34) | 221 (593) (0.37) | 0.91 | 0.71 to 1.15 | 0.89 | 0.70 to 1.14 |
Intention-to-treat and per-protocol analyses.
*All children randomised were followed from randomisation to 15 months of age and analysed according to randomisation group.
†Number of children.
‡Mean hospitalisation per child.
§Adjusted for baseline characteristics (sex, prematurity, study site, caesarean section, antibiotics during delivery, multiple birth, birth weight, child age at randomisation, maternal age, parental ethnicity (≥1 parent of ethnicity other than Danish), maternal education, parents living together, maternal BCG (by maternal recall), siblings, maternal atopy and maternal smoking during pregnancy).
¶Prematurity defined as birth before 37 weeks of gestation.
**Children having received the BCG vaccine but randomised to control group, or vice versa were excluded. The remaining children were followed from time since vaccination for the BCG group and time since randomisation for control children.