Table 6.
Outcome measures and breakdown of demographic variables across experimental conditionsa
| Treatment Group | Overall | χ2/F (df) b | p | ||||
|---|---|---|---|---|---|---|---|
| Control | Letter | Reminder | Letter & Reminder | ||||
| % Children vaccinated in the school year (mean (SD)) | 61.57 (15.61) | 61.94 (15.60) | 63.53 (14.13) | 62.87 (14.04) | 62.47 (14.88) | 2.68 (32990) | 0.046 |
| % Consent forms returned | 73.55 (15.85) | 75.67 (15.43) | 76.18 (14.72) | 75.97 (14.19) | 75.34 (15.1) | 4.84 (3, 2990) | 0.002 |
| % Consent given | 64.92 (15.07) | 65.46 (15.58) | 66.96 (13.89) | 66.32 (13.55) | 65.91 (14.57) | 2.91 (3, 2990) | 0.033 |
| % Consent refused | 8.63 (7.33) | 10.21 (8.70) | 9.22 (8.13) | 9.65 (7.71) | 9.43 (8.00) | 5.23 (32990) | 0.001 |
| Number of flu vaccine doses given in the school year (mean (SD)) | 27.75 (16.71) | 27.98 (17.90) | 27.95 (16.48) | 28.21 (18.04) | 27.97 (17.28) | 0.09 (3, 2990) | 0.967 |
| Children eligible for flu vaccine in the school year (mean (SD)) | 45.86 (26.09) | 45.22 (26.24) | 45.22 (26.24) | 45.41 (28.13) | 45.59 (27.05) | 0.11 (3, 2990) | 0.953 |
| Number of consent given | 29.26 (17.28) | 29.46 (18.66) | 29.55 (17.26) | 29.67 (18.78) | 29.49 (18) | 0.07 (3, 2990) | 0.976 |
| Number of consent refused | 3.79 (3.68) | 4.66 (4.84) | 3.94 (3.70) | 4.19 (3.86) | 4.14 (4.06) | 6.64 (3, 2990) | 0.000 |
| Number of consent returned | 33.05 (19.17) | 34.12 (21.45) | 33.49 (19.33) | 33.86 (21.14) | 33.63 (20.29) | 0.39 (3, 2990) | 0.759 |
| % Eligible for free school meals in the school (mean (SD)) | 12.18 (9.74) | 11.18 (9.13) | 12.48 (9.93) | 12.33 (9.17) | 12.04 (9.51) | 2.88 (32990) | 0.035 |
| Average ethnic composition of school | |||||||
| % White | 85.42 | 83.87 | 84. 18 | 84.69 | 84.54 | 0.98 (3, 2990) | 0.402 |
| % Mixed | 4.85 | 4.92 | 4.68 | 4.54 | 4.75 | 2.28 (3, 2990) | 0.077 |
| % Asian | 4.85 | 6.59 | 6.49 | 6.02 | 5.99 | 2.32 (3, 2990) | 0.073 |
| % Black | 3.01 | 2.92 | 2.86 | 2.83 | 2.84 | 0.14 (3, 2990) | 0.939 |
| % Other | 1.13 | 1.14 | 1.23 | 1.12 | 1.16 | 0.57 (3, 2990) | 0.632 |
| Religious denomination of the school (n (%)) | 57.41 (15) | < 0.001 | |||||
| Catholic | 56 (7.46) | 52 (6.87) | 77 (10.24) | 24 (3.27) | 209 (6.98) | ||
| Church of England | 229 (30.49) | 222 (29.33) | 205 (27.26) | 239 (32.56) | 895 (29.89) | ||
| Other Christian Faith | 0 (0) | 0 (0) | 0 (0) | 3 (0.41) | 3 (0.10) | ||
| Sikh | 0 (0) | 0 (0) | 3 (0.40) | 0 (0) | 3 (0.10) | ||
| Other | 0 (0) | 0 (0) | 3 (0.40) | 0 (0) | 3 (0.10) | ||
| No religion | 466 (62.05) | 483 (63.80) | 464 (61.70) | 468 (63.76) | 1881 (62.83) | ||
| Deprivation (n (%)) | 3.880 (3) | 0.275 | |||||
| High | 83 (11.05) | 88 (11.62) | 102 (13.56) | 77 (10.49) | 350 (11.69) | ||
| Low | 668 (88.95) | 669 (88.46) | 650 (86.44) | 657 (89.51) | 2644 (88.31) | ||
| Urban/rural area (n (%)) | 13.226 (3) | 0.004 | |||||
| Urban | 512 (68.18) | 497 (65.65) | 525 (69.81) | 451 (61.44) | 1985 (66.30) | ||
| Rural | 239 (31.82) | 260 (34.35) | 227 (30.19) | 283 (38.56) | 1009 (33.70) | ||
| School Year (n (%)) | 0.173 (6) | 1.000 | |||||
| 1 | 252 (33.55) | 251 (33.16) | 251 (33.38) | 243 (33.11) | 997 (33.30) | ||
| 2 | 251 (33.42) | 252 (33.29) | 254 (33.78) | 244 (33.24) | 1001 (33.43) | ||
| 3 | 248 (33.02) | 254 (33.55) | 247 (32.85) | 247 (33.65) | 996 (33.27) | ||
aFor 16 schools in the trial, an inconsistency in the data for number of consent forms returned led us to drop these observations from analysis
of return of consent forms, though they were included in the analysis of the primary outcome measure (uptake)
bChi square/ one-way ANOVA tests, as appropriate