Monthly reports of health service use and duration of illness (weeks 4, 8, 12, 16 and 20) for participants who reported at least one respiratory infection during the 20 weeks
| Control | Intervention | Univariate risk ratio (95% CI; p value) | Multivariate risk ratio* (95% CI; p=value) | |
|---|---|---|---|---|
| Reported episodes of respiratory tract infection | 1665/5697 (29.23%) | 1578/5291 (29.82%) | 1.03 (0.93 to 1.12; p=0.566) | 1.04 (0.94 to 1.14; p=0.461) |
| Of those who reported a respiratory tract infection | ||||
| Saw a doctor about illness (as a proportion of the number of episodes) | 304/1664 (18.27%) | 239/1574 (15.18%) | 0.75 (0.56 to 1.01; p=0.061) | 0.71 (0.52 to 0.98; p=0.037) |
| Contacted NHS Direct about illness | 20/1661 (1.20%) | 37/1574 (2.35%) | 2.34 (1.07 to 5.10; p=0.034) | 2.25 (1.00 to 5.07; p=0.048) |
| Difference (95% CI; p value) | ||||
| Length of illness (days) | 10.68 (9.45) | 11.30 (9.89) | 0.58 (−0.15 to 1.30; p=0.119) | 0.60 (−0.15 to 1.36; p=0.118) |
| Days moderately bad or worse NHS, National Health Service | 4.00 (5.48) | 4.59 (6.88) | 0.47 (0.03 to 0.92; p=0.035) | 0.52 (0.06 to 0.97; p=0.026) |
*Multivariate model controls for gender, age, highest educational qualification, smoking status, whether there are children aged under 16 years living in the household, any comorbid condition, index of multiple deprivation score, and the number of times the patient reported consulting a doctor about an RTI in the 12 months prior to the study.