Using natural language processing for identification of pneumonia cases from clinical records of patients with serologically proven influenza.

The purpose of this study was to determine whether influenza vaccination protects against pneumonia in patients who develop influenza. By parsing a data set of records of 1455 patients with serologically proven influenza using SNOMED CT we found that of the vaccinated patients 19.3% developed pneumonia and of the unvaccinated 20.7%. These data suggest that influenza vaccine does not prevent pneumonias in patients who develop influenza despite immunization with influenza vaccine.