The unadjusted postintervention duration of an outbreak in long-term care facilities affected by influenza outbreaks in Alberta, Canada, 2013/2014 and 2014/2015 influenza seasons
| Characteristics (N=127) | Mean (SE) (days) | 95% CI (days) | p Value |
|---|---|---|---|
| Average | |||
| 12.35 (0.43) | 11.50 to 13.21 | − | |
| Location | |||
| Major urban centre | 13.08 (0.50) | 12.09 to 14.07 | − |
| Other | 10.72 (0.79) | 9.16 to 12.28 | 0.011 |
| Year | |||
| 2013–2014 | 13.61 (1.22) | 11.20 to 16.02 | − |
| 2014–2015 | 12.15 (0.46) | 11.24 to 13.06 | 0.238 |
| Primary strain | |||
| Influenza A | 12.38 (0.45) | 11.48 to 13.27 | − |
| Influenza B | 12.27 (1.19) | 9.91 to 14.63 | 0.921 |
| Mixed strain | |||
| Single | 11.56 (0.44) | 10.68 to 12.44 | − |
| Mixed | 15.30 (1.03) | 13.25 to 17.34 | <0.0001 |
| Outbreak progression time (T2–T1) | |||
| Short | 13.83 (0.74) | 12.37 to 15.29 | − |
| Medium | 11.13 (0.70) | 9.74 to 12.51 | 0.009 |
| Long | 11.85 (0.75) | 10.37 to 13.33 | 0.055 |
| Prevalence of ILI during outbreak progression | |||
| Low | 13.43 (0.67) | 12.11 to 14.76 | − |
| Medium | 12.59 (0.75) | 11.11 to 14.06 | 0.419 |
| High | 10.95 (0.79) | 9.38 to 12.52 | 0.017 |
| Oseltamivir IP decision-making time (T3–T2) | |||
| Short | 11.72 (0.63) | 10.46 to 12.97 | − |
| Medium | 13.36 (0.63) | 12.12 to 14.61 | 0.111 |
| Long | 12.42 (1.03) | 10.37 to 14.47 | 0.514 |
| Timing of oseltamivir intervention | |||
| Very early in outbreak | 15.30 (0.73) | 13.86 to 16.75 | − |
| Early in outbreak | 12.62 (0.64) | 11.36 to 13.89 | 0.004 |
| Late in outbreak | 9.07 (0.53) | 8.03 to 10.12 | <0.0001 |
| Number of residents at risk at intervention | |||
| 1st tertile | 9.47 (0.63) | 8.23 to 10.71 | − |
| 2nd tertile | 12.58 (0.65) | 11.30 to 13.85 | 0.001 |
| 3rd tertile | 15.24 (0.69) | 13.87 to 16.61 | <0.0001 |
ILI, influenza-like illness; IP, influenza prophylaxis.