Electronic nudges to increase influenza vaccination uptake among patients with heart failure: a prespecified analysis of the NUDGE-FLU trial.

Approximately 1 in 4 patients with HF did not receive influenza vaccination with a pronounced implementation gap in those <65 years where less than half were vaccinated. HF status did not modify the effectiveness of cardiovascular gain-framed and repeated electronic nudging letters in increasing influenza vaccination rates. No unintended negative effects on longitudinal GDMT use were observed.