Respiratory outcomes by allocation
| Active (n=137) | Control (n=103) | Adjusted HR/OR/incidence rate ratio/ratio of geometric means (95% CI)* | p Value | |
|---|---|---|---|---|
| ARI (upper or lower) | ||||
| Median time to first ARI, days (IQR) | 203 (55 to --) | 227 (83 to --) | 1.18 (0.84 to 1.66) | 0.34 |
| Proportion of participants with ≥1 ARI (%)† | 83/125 (66%) | 58/92 (63%) | 1.21 (0.68 to 2.15) | 0.52 |
| Rate of ARI per participant-year | 279/130.0=2.15 | 185/93.6=1.98 | 1.15 (0.84 to 1.58) | 0.37 |
| Median duration of symptoms per ARI, days (IQR)‡ | 6 (3 to 13) | 5 (3 to 11) | 1.17 (0.92 to 1.49) | 0.21 |
| URI | ||||
| Median time to first URI, days (IQR) | 247 (75 to --) | -- (107 to --) | 1.48 (1.02 to 2.16) | 0.039 |
| Proportion of participants with ≥1 URI (%)† | 77/124 (62%) | 45/91 (49%) | 1.83 (0.99 to 3.41) | 0.055 |
| Rate of URI per participant-year | 149/130.0=1.15 | 94/93.6=1.00 | 1.34 (0.94 to 1.90) | 0.10 |
| Median duration of symptoms per URI, days (IQR)‡ | 7 (4 to 12) | 5 (3 to 10) | 1.34 (1.09 to 1.65) | 0.005 |
| Median peak Jackson symptom score per URI (IQR)§ | 9 (6 to 14) | 8 (5 to12) | 1.11 (0.91 to 1.35) | 0.30 |
| LRI | ||||
| Median time to first LRI, days (IQR)¶ | -- (109 to --) | -- (137 to --) | 1.12 (0.75 to 1.66) | 0.57 |
| Proportion of participants with ≥1 LRI (%)† | 63/124 (51%) | 44/90 (49%) | 1.11 (0.64 to 1.92) | 0.72 |
| Rate of LRI per participant-year | 130/130.0=1.00 | 91/93.6=0.97 | 1.06 (0.71 to 1.58) | 0.77 |
| Median duration of symptoms per LRI, days (IQR)‡ | 6 (2 to 13) | 5 (3 to 11) | 1.07 (0.76 to 1.51) | 0.70 |
| Median peak Macfarlane symptom score per LRI (IQR)¶ | 4 (3 to 7) | 4 (3 to 6) | 1.11 (0.92 to 1.33) | 0.27 |
*Adjusted for study group (resident vs carer) and minimisation variables (level of care, size of scheme and season of randomisation).
†These analyses exclude participants who withdrew from the trial without experiencing ARI/URI/LRI prior to date of withdrawal.
‡Duration of symptoms defined as the number of consecutive days associated with a URI/LRI in which the total Jackson/Macfarlane symptom score is greater than the median total Jackson/Macfarlane symptom score recorded during the run-in period.
§Jackson symptoms (sneezing, sore throat, headache, subjective sensation of fever or chilliness, malaise, nasal discharge, nasal obstruction, cough) each scored from 0 (no symptoms) to 3 (severe symptoms) and summed to calculate symptom score; peak score is the highest total symptom score recorded during the course of the URI.
¶Macfarlane symptoms (cough, sputum production, dyspnoea, wheeze, chest pain/discomfort) each scored from 0 (no symptoms) to 3 (severe symptoms) and summed to calculate symptom score; peak score is the highest total symptom score recorded during the course of the URI.
--, undefined; ARI, acute respiratory infection; LRI, lower respiratory infection; URI, upper respiratory infection.