The authors previously conducted a trial (called NUDGE-FLU) during the 2022-2023 influenza season in Denmark, where the government is using Digital Post, an online email service available to most citizens aged 15 and over. box) is maintained. As part of the NUDGE-FLU trial, the authors sent messages to adults 65 and older through digital posts and concluded that these electronic reminders may improve influenza vaccine uptake. In the Nature Medicine study, the authors were interested in whether the benefits of sending these electronic reminders were consistent across consecutive flu seasons. The authors relied on a cohort of 881,373 older adults, representing 70.4% of the total study population in Denmark. Participants were randomly assigned to seven different groups to influence the number of messages they received through Digital Post or the content of messages they received about influenza vaccination. For example, participants in one group were sent standard notifications about the upcoming flu season informing them that they were eligible for a free vaccination. In other groups, this standard message includes text informing participants about the risk of cardiovascular disease, respiratory complications, or the benefits of influenza vaccination in limiting the spread of infection to friends and family. Added. Alternatively, participants may have received two standard messages or one message with a link to directly book a vaccination appointment within approximately two weeks. Finally, as a controlled comparison, some older adults did not receive nudges or reminders about the flu vaccine through digital posts.
The authors observed a 0.31% increase in vaccinations by the end of the year when tallying all participants who received some kind of digital nudge, compared to participants who did not receive an electronic reminder. There were no significant differences in vaccination rates when taking into account participants’ age, gender, geographic location in Denmark, disease status, or whether they participated in the first NUDGE-FLU trial. Participants who received electronic reminders were more likely to get vaccinated earlier in the year, but the authors wonder whether a single type of reminder or letter would have a significant benefit in increasing vaccination rates. could not be determined.