Validation of self-reported influenza vaccination in the current and prior season.

Self-reported influenza vaccination is generally accurate for the current season, but the accuracy of self-report for vaccination in prior seasons is largely unknown. This study evaluated the accuracy of self-report for current and prior season influenza vaccination among patients with medically attended acute respiratory illness enrolled in a study of influenza vaccine effectiveness during the 2014-15 influenza season. It demonstrates there is a greater potential for exposure misclassification when prior season vaccinations are ascertained by self-report. Percent agreement between self-report and final status was high for both current and prior season vaccination: 97.7% and 93.2%, respectively.