The Effect of AUDIT and Feedback on Pneumococcal Vaccination Coverage

The goal of this cluster-randomized trial is to study the effect of Audit and Feedback loops on pneumococcal vaccination coverage rate in adults at risk in general practice. The main questions it aims to answer are: * To assess the effect of "clinical AUDIT and feedback" loops on the pneumococcal vaccination coverage rate in adults at risk in general practice. * To explore whether the increase in vaccination coverage rate after implementation of Audit and Feedback loops is different in specific subgroups (risk groups, male/female, age, smoking status). Every general practice center assigned to the control or intervention group will have access to a clinical AUDIT to identify patients that may benefit from a pneumococcal vaccination. The general practice centers in the intervention group will also receive an individualized extended electronic feedback report, with multiple components like benchmarked performances and action plans, at baseline and each 2 months from baseline onwards.