Numbers of pneumonia patients (first episode) in a prospective randomised trial showing efficacy of 23-serotype pneumococcal vaccine
| Intervention group | Non-intervention group | Vaccine efficacy* | p value† | NNT | |||||
|---|---|---|---|---|---|---|---|---|---|
| n | N | n | N | % | 95% CI | n | 95% CI | ||
| CAP-PN, community acquired pneumonia of unknown aetiology and pneumococcal pneumonia; FEV1, forced expiratory volume in 1 second; NNT, number needed to treat. | |||||||||
| *Vaccine efficacy = 1 − RR × 100. | |||||||||
| †The p value for pneumococcal pneumonia is 0.06 using the Fisher’s exact test (two sided) and 0.03 (single sided). This last p value is very similar to that obtained with the log rank test (p = 0.025, Kaplan-Meier curves). | |||||||||
| CAP-PN | |||||||||
| All patients | 25 | 298 | 33 | 298 | 24 | (−24 to 54) | 0.333 | ||
| <65 years | 3 | 91 | 16 | 116 | 76 | (20 to 93) | 0.013 | 10 | (6 to 31) |
| ⩾65 years | 22 | 207 | 17 | 182 | −14 | (−107 to 38) | 0.801 | ||
| FEV1 <40% | 12 | 132 | 20 | 114 | 48 | (−7 to 80) | 0.076 | ||
| FEV1 ⩾40% | 13 | 166 | 13 | 184 | −11 | (−132 to 47) | 0.945 | ||
| Age <65 years and FEV1 <40% | 1 | 46 | 10 | 40 | 91 | (35 to 99) | 0.002 | 3 | (2 to 4) |
| Pneumococcal pneumonia | 0 | 298 | 5 | 298 | 0.061 | ||||