Electronic Nudge for Flu Vaccination Does Not Improve Clinical Outcomes

Electronic letters incorporating cardiovascular (CV) gain framing and repeated messaging, which increase influenza vaccination, do not translate into improvement in clinical outcomes, according to a study published online March 19 in the Annals of Internal Medicine.

Niklas Dyrby Johansen, M.D., from Copenhagen University Hospital-Herlev and Gentofte in Denmark, and colleagues examined the effects of the successful nudging interventions seen with the Nationwide Utilization of Danish Government Electronic letter system for increasing inFLUenza vaccine uptake (NUDGE-FLU) trial on downstream clinical outcomes in the 2022 to 2023 influenza season. Data were included for 964,870 Danish citizens aged 65 years or older who received usual care or nine different electronically delivered behavioral nudging letters; the analysis set included 691,820 participants.

The researchers found that 1.0 percent of participants in the usual-care group, 1.0 percent in the CV gain-framing group, and 1.1 percent in the repeated-letter group had hospitalization for pneumonia or influenza. Overall, 12.9, 13.0, and 13.0 percent of participants in the usual-care group, the CV gain-framing group, and the repeated-letter group, respectively, were hospitalized for any cause. There was also no significant difference seen in mortality, with 1.8, 1.9, and 1.7 percent of participants in the usual-care, CV gain-framing, and repeated-letter groups, respectively.

“The modest increases in influenza vaccination rates seen with electronic nudging letters did not confer observable improvements in clinical outcomes,” the authors write.

The study was funded by Sanofi.

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