Vila‐Corcoles 2006.

Methods	Prospective cohort study
Participants	Community‐dwelling older adults aged 65 years and above, assigned to primary healthcare centres
Interventions	11,241 members of the cohort. Study period from January 2002 until April 2005 23‐valent PPV
Outcomes	B1. IPD (immunocompetent and immunocompetent elderly) B2. Vaccine‐type IPD (immunocompetent and immunocompetent elderly)
Notes	Cohort observed until study completion or first occurrence of each outcome (maximum 3 years, 4 months) IPD incidence of study participants 0.64/1000 person‐years Model adjusted for age, sex, number of outpatient visits, history of hospitalisation for pneumonia in previous 24 months, influenza vaccination status, underlying medical conditions, current smoking status and immunocompromised status. Vaccination was a time variable factor; considered vaccinated from 14 days following administration Results for IPD by vaccine‐type only serotypes provided by personal communication with first author
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Non‐random study
Allocation concealment (selection bias)	Low risk	Investigators reviewing clinical data unaware of vaccination status
Confounding All outcomes	Low risk	6/6 important confounding factors considered
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	NA
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Due to specificity of outcome
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not described
Selective reporting (reporting bias)	Low risk	Limited extent to which analysis could have been manipulated to bias the findings

CAP: community‐acquired pneumonia 
 FEV: forced expiratory volume 
 FEV₁: forced expiratory volume in first second 
 HMO: health maintenance organisation 
 IPD: invasive pneumococcal disease 
 NA: not applicable 
 PPV: pneumococcal polysaccharide vaccine 
 RCT: randomised controlled trial