| Methods |
RCT |
| Participants |
Participants diagnosed with chronic obstructive airways disease by spirometry at the University Hospital of Valme, Spain (n = 600). Participants excluded if received previous pneumococcal vaccination, pregnant, immunosuppressed, in dialysis, HIV+, asplenia |
| Interventions |
23‐valent PPV (n = 300) or no vaccine (n = 300). The study ran from 1999 to 2004 and follow‐up was 6 monthly, up to three years |
| Outcomes |
A1. IPD
A2. Pneumonia (all causes)
A5. Definitive pneumococcal pneumonia
A7. Presumptive pneumococcal pneumonia |
| Notes |
Case ascertainment: participant to contact doctor if temperature greater than 38 C
Primary outcome was time to first episode of CAP
Patients assigned vaccine/no vaccine from a computer‐generated random number sequence. No reference to blinding
No reference to sample size calculation |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
Computer‐generated random number sequence |
| Allocation concealment (selection bias) |
Unclear risk |
Method not described (nor a placebo used, potentially high risk of bias) |
| Confounding
All outcomes |
Unclear risk |
NA |
| Blinding of participants and personnel (performance bias)
All outcomes |
Unclear risk |
Not described. Participants probably aware due to receipt of 2 vaccines |
| Blinding of outcome assessment (detection bias)
All outcomes |
Low risk |
Physicians participating in the 3‐year follow‐up were unaware of the group to which individuals were assigned |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
No evidence of incomplete outcome data |
| Selective reporting (reporting bias) |
Low risk |
No evidence of selective outcome reporting |
