Daily Dose: Electronic “Nudges” to Increase Flu Vaccination Uptake

Patient Care brings primary care clinicians a lot of medical news every day—it’s easy to miss an important study. The Daily Dose provides a concise summary of one of the website's leading stories you may not have seen.

On March 9, 2023, we reported on a study abstract presented at the American College of Cardiology’s (ACC) 2023 Annual Scientific Session Together with the World Congress of Cardiology and published simultaneously online in The Lancet that examined whether behavioral nudges delivered via a governmental electronic letter system, would increase influenza vaccination uptake among older adults in Denmark.

The study

In the NUDGE-FLU trial, researchers randomized 964 870 Danish citizens (mean age, 74 years; 51% women) across 691 820 households to receive usual care or to receive an electronic letter containing 1 of 9 specific messages about the upcoming influenza season and the need for vaccination to determine which “behavioral nudge,” if any, would increase vaccine uptake among older adults. The letters were delivered via Denmark’s electronic letter system on September 16, 2022. The primary endpoint was the receipt of influenza vaccination on or before January 1, 2023. The messages delivered in the electronic letters ranged from a basic letter without name personalization to one highlighting the potential CV benefits of the influenza vaccine such as protection against myocardial infarction (MI), heart failure (HF), and other cardiovascular diseases (CVDs), one offering a recommendation from a leading health authority, and one considered a loss-framing note emphasizing that low uptake of flu vaccination places individuals and their loved ones at risk.

Subsequent influenza vaccine uptake was higher in 2 groups compared with the usual care group: those who received the electronic letter highlighting the potential CV benefits (81% vs 80.12%; P<.001) and those who received repeated letters, ie, the first at randomization and a reminder at day 14 (80.85% vs 80.12%; P=.0006).

Note from authors

"In a country with a high background rate of influenza vaccination, certain behaviourally informed, electronic nudges delivered in advance of vaccine availability incrementally increased vaccine uptake (approximately 1% absolute increase). Although the magnitude of effectiveness of the successful nudging strategies might seem modest, the lowtouch, inexpensive, and highly scalable nature of these electronic letters might have important population-level public health implications."

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