Investigating adverse events following immunisation with pneumococcal polysaccharide vaccine using electronic General Practice data

Highlights • 23vPPV booster recommendations were changed in 2011 following an increase in AEFI reports. • A post-hoc analysis of electronic data from 250 General Practices was conducted to verify the signal. • It was 10-15 times more sensitive than passive reporting, enough to detect a 3-fold increase. • The original apparent signal appears to have been an artefact. • This data source has substantial potential, but would need to be larger and available in real time.