Table 5 Effectiveness of PPV23 in patients ≥75 years of age at different intervals after vaccination, estimated by the indirect cohort (Broome) method, July 2008 to June 2016 (n = 1051)
Time since PPV23 vaccination | Cases | Controls | Crude VE (%) | 95%CI | Adjusted VE (%) | 95%CI |
|---|---|---|---|---|---|---|
No vaccination | 598 | 118 | Ref. | Ref. | ||
≤ 1 years | 29 | 11 | 48.0 | (−7.0 to 74.7) | 73.7 | (39.0 to 88.7) |
> 1 and ≤ 2 years | 41 | 15 | 46.1 | (−0.6 to 71.1) | 64.4 | (29.2 to 82.0) |
> 2 and ≤ 3 years | 37 | 14 | 47.9 | (0.5 to 72.7) | 48.9 | (−1.6 to 74.3) |
> 3 and ≤ 4 years | 46 | 13 | 30.2 | (−33.3 to 63.4) | 19.2 | (−61.3 to 59.5) |
> 4 and ≤ 5 years | 26 | 8 | 35.9 | (−45.1 to 71.7) | −3.4 | (−144.9 to 56.3) |
> 5 years | 70 | 25 | 44.7 | (9.1 to 66.4) | 15.5 | (−47.1 to 51.4) |